startup.rst revision 867b9ec6
1.. _startup:
2
3=======================================
4VPP Configuration File - 'startup.conf'
5=======================================
6
7
8After a successful installation, VPP installs a startup config file named
9*startup.conf* in the */etc/vpp/* directory. This file can be tailored to
10make VPP run as desired, but contains default values for typical installations.
11
12Below are more details about this file and the parameters and values it contains.
13
14Introduction
15------------
16
17The VPP network stack comes with several configuration options that can be
18provided either on the command line when VPP is started, or in a configuration
19file. Specific applications built on the stack have been known to require a dozen
20arguments, depending on requirements.
21
22Command-line Arguments
23----------------------
24
25Parameters are grouped by a section name. When providing more than one
26parameter to a section, all parameters for that section must be wrapped in
27curly braces. For example, to start VPP with configuration data via the
28command line with the section name *'unix'*:
29
30.. code-block:: console
31
32    $ sudo /usr/bin/vpp unix { interactive cli-listen 127.0.0.1:5002 }
33
34The command line can be presented as a single string or as several; anything
35given on the command line is concatenated with spaces into a single string
36before parsing. VPP applications must be able to locate their own executable
37images. The simplest way to ensure this will work is to invoke a VPP
38application by giving its absolute path. For example:
39*'/usr/bin/vpp <options>'*  At startup, VPP applications parse through their
40own ELF-sections [primarily] to make lists of init, configuration, and exit
41handlers.
42
43When developing with VPP, in gdb it's often sufficient to start an application
44like this:
45
46.. code-block:: console
47
48    (gdb) run unix interactive
49
50Configuration File
51------------------
52
53It is also possible to supply the configuration parameters in a startup
54configuration. The path of the file is provided to the VPP application on its
55command line. The format of the configuration file is a simple text file with
56the same content as the command line, but with the benefit of being able to use
57newlines to make the content easier to read. For example:
58
59.. code-block:: console
60
61    $ cat /etc/vpp/startup.conf
62    unix {
63      nodaemon
64      log /var/log/vpp/vpp.log
65      full-coredump
66      cli-listen localhost:5002
67    }
68    
69    api-trace {
70      on
71    }
72    
73    dpdk {
74      dev 0000:03:00.0
75    }
76
77VPP is then instructed to load this file with the -c option. For example:
78
79.. code-block:: console
80
81    $ sudo /usr/bin/vpp -c /etc/vpp/startup.conf
82
83When the VPP service is started, VPP is started with this option via another
84installed file, vpp.service (Ubuntu: /lib/systemd/system/vpp.service and
85CentOS: /usr/lib/systemd/system/vpp.service). See *'ExecStart'* below:
86
87.. code-block:: console
88
89    $ cat /lib/systemd/system/vpp.service
90    [Unit]
91    Description=vector packet processing engine
92    After=network.target
93    
94    [Service]
95    Type=simple
96    ExecStartPre=-/bin/rm -f /dev/shm/db /dev/shm/global_vm /dev/shm/vpe-api
97    ExecStartPre=-/sbin/modprobe uio_pci_generic
98    ExecStart=/usr/bin/vpp -c /etc/vpp/startup.conf
99    ExecStopPost=/bin/rm -f /dev/shm/db /dev/shm/global_vm /dev/shm/vpe-api
100    Restart=always
101    
102    [Install]
103    WantedBy=multi-user.target
104
105
106Configuration Parameters
107------------------------
108
109Below is the list of section names and their associated parameters. This is not
110an exhaustive list of parameters available. The command-line argument parsers
111can be found in the source code by searching for instances of the
112**VLIB_CONFIG_FUNCTION** and **VLIB_EARLY_CONFIG_FUNCTION** macro.
113
114For example, the invocation *'VLIB_CONFIG_FUNCTION (foo_config, "foo")'* will
115cause the function *'foo_config'* to receive all parameters given in a
116parameter block named "foo": "foo { arg1 arg2 arg3 ... }". 
117
118
119List of Basic Parameters:
120-------------------------
121
122| unix_ 
123| dpdk_ 
124| cpu_  
125
126List of Advanced Parameters:
127----------------------------
128
129| acl-plugin_ 
130| api-queue_
131| api-segment_
132| api-trace_
133| buffers_
134| cj_
135| dns_
136| heapsize_
137| ip_
138| ip6_
139| l2learn_
140| l2tp_
141| logging_
142| mactime_
143| map_
144| mc_
145| nat_
146| oam_
147| plugins_
148| plugin_path_
149| punt_
150| session_
151| socketsvr_
152| stats_
153| statseg_
154| tapcli_
155| tcp_
156| tls_
157| tuntap_
158| vhost-user_
159| vlib_
160
161.. _unix:
162
163"unix" Parameters
164_________________
165
166Configure VPP startup and behavior type attributes, as well and any OS based
167attributes.
168
169 * **interactive**
170     Attach CLI to stdin/out and provide a debugging command line interface.
171     Implies nodaemon.
172     
173     **Example:** interactive
174     
175 * **nodaemon**
176     Do not fork / background the vpp process. Typical when invoking VPP
177     applications from a process monitor. Set by default in the default
178     *'startup.conf'* file.
179     
180     **Example:** nodaemon
181     
182 * **log <filename>**
183     Logs the startup configuration and all subsequent CLI commands in filename.
184     Very useful in situations where folks don't remember or can't be bothered
185     to include CLI commands in bug reports. The default *'startup.conf'* file
186     is to write to *'/var/log/vpp/vpp.log'*.
187     
188     In VPP 18.04, the default log file location was moved from '/tmp/vpp.log'
189     to '/var/log/vpp/vpp.log' . The VPP code is indifferent to the file location.
190     However, if SELinux is enabled, then the new location is required for the file
191     to be properly labeled. Check your local *'startup.conf'* file for the log file
192     location on your system.
193     
194     **Example:** log /var/log/vpp/vpp-debug.log
195     
196 * **exec|startup-config <filename>**
197     Read startup operational configuration from filename. The contents of the file
198     will be performed as though entered at the CLI. The two keywords are aliases
199     for the same function; if both are specified, only the last will have an effect.
200     The file contains CLI commands, for example:
201
202     | $ cat /usr/share/vpp/scripts/interface-up.txt
203     | set interface state TenGigabitEthernet1/0/0 up
204     | set interface state TenGigabitEthernet1/0/1 up
205     
206     **Example:** startup-config /usr/share/vpp/scripts/interface-up.txt
207     
208 * **gid number|name>**
209     Sets the effective group ID to the input group ID or group name of the calling
210     process.
211     
212     **Example:** gid vpp
213     
214 * **full-coredump**
215     Ask the Linux kernel to dump all memory-mapped address regions, instead of
216     just text+data+bss.
217     
218     **Example:** full-coredump
219     
220 * **coredump-size unlimited|<n>G|<n>M|<n>K|<n>**
221     Set the maximum size of the coredump file. The input value can be set in
222     GB, MB, KB or bytes, or set to *'unlimited'*.
223     
224     **Example:** coredump-size unlimited
225     
226 * **cli-listen <ipaddress:port>|<socket-path>**
227     Bind the CLI to listen at address localhost on TCP port 5002. This will
228     accept an ipaddress:port pair or a filesystem path; in the latter case a
229     local Unix socket is opened instead. The default *'startup.conf'* file
230     is to open the socket *'/run/vpp/cli.sock'*.
231     
232     **Example:** cli-listen localhost:5002
233     **Example:** cli-listen /run/vpp/cli.sock
234     
235 * **cli-line-mode**
236     Disable character-by-character I/O on stdin. Useful when combined with,
237     for example, emacs M-x gud-gdb.
238     
239     **Example:** cli-line-mode
240     
241 * **cli-prompt <string>**
242     Configure the CLI prompt to be string.
243     
244     **Example:** cli-prompt vpp-2
245     
246 * **cli-history-limit <n>**
247     Limit command history to <n> lines. A value of 0 disables command history.
248     Default value: 50
249     
250     **Example:** cli-history-limit 100
251     
252 * **cli-no-banner**
253     Disable the login banner on stdin and Telnet connections.
254     
255     **Example:** cli-no-banner
256     
257 * **cli-no-pager**
258     Disable the output pager.
259     
260     **Example:** cli-no-pager
261     
262 * **cli-pager-buffer-limit <n>**
263     Limit pager buffer to <n> lines of output. A value of 0 disables the
264     pager. Default value: 100000
265     
266     **Example:** cli-pager-buffer-limit 5000
267     
268 * **runtime-dir <dir>**
269     Set the runtime directory, which is the default location for certain
270     files, like socket files. Default is based on User ID used to start VPP.
271     Typically it is *'root'*, which defaults to *'/run/vpp/'*. Otherwise,
272     defaults to *'/run/user/<uid>/vpp/'*.
273     
274     **Example:** runtime-dir /tmp/vpp
275     
276 * **poll-sleep-usec <n>**
277     Add a fixed-sleep between main loop poll. Default is 0, which is not to
278     sleep.
279     
280     **Example:** poll-sleep-usec 100
281     
282 * **pidfile <filename>**
283     Writes the pid of the main thread in the given filename.
284     
285     **Example:** pidfile /run/vpp/vpp1.pid
286
287.. _dpdk:
288
289"dpdk" Parameters
290_________________
291
292Command line DPDK configuration controls a number of parameters, including
293device whitelisting, the number of CPUs available for launching
294dpdk-eal-controlled threads, the number of I/O buffers, and the process
295affinity mask. In addition, the DPDK configuration function attempts to support
296all of the DPDK EAL configuration parameters.
297
298All of the DPDK EAL options should be available.
299See ../src/plugins/dpdk/device/dpdk_priv.h, look at the set of
300"foreach_eal_XXX" macros.
301
302Popular options include:
303 * **dev <pci-dev>**
304     White-list [as in, attempt to drive] a specific PCI device. PCI-dev is a
305     string of the form "DDDD:BB:SS.F" where:
306     
307        | DDDD = Domain
308        | BB = Bus Number
309        | SS = Slot number
310        | F = Function
311     
312     This is the same format used in the linux sysfs tree (i.e.
313     /sys/bus/pci/devices) for PCI device directory names.
314     
315     **Example:** dev 0000:02:00.0
316     
317 * **dev <pci-dev> { .. }**
318     When whitelisting specific interfaces by specifying PCI address,
319     additional custom parameters can also be specified. Valid options include:
320
321      * **num-rx-queues <n>**
322          Number of receive queues. Also enables RSS. Default value is 1.
323      * **num-tx-queues <n>**
324          Number of transmit queues. Default is equal to number of worker
325          threads or 1 if no workers treads.
326      * **num-rx-desc <n>**
327          Number of descriptors in receive ring. Increasing or reducing number
328          can impact performance. Default is 1024.
329      * **num-rt-desc <n>**
330          Number of descriptors in transmit ring. Increasing or reducing number
331          can impact performance. Default is 1024.
332      * **workers**
333          TBD
334      * **vlan-strip-offload on|off**:
335          VLAN strip offload mode for interface. VLAN stripping is off by default
336          for all NICs except VICs, using ENIC driver, which has VLAN stripping on
337          by default.
338      * **hqos**
339          Enable the Hierarchical Quality-of-Service (HQoS) scheduler, default is
340          disabled. This enables HQoS on specific output interface.
341      * **hqos { .. }**
342          HQoS can also have its own set of custom parameters. Setting a custom
343          parameter also enables HQoS.
344
345          * **hqos-thread <n>**
346              HQoS thread used by this interface. To setup a pool of threads that
347              are shared by all HQoS interfaces, set via the*'cpu'* section using
348              either *'corelist-hqos-threads'* or *'coremask-hqos-threads'*.
349
350      * **rss**
351          TBD
352     
353     **Example:**
354     
355                 | dev 0000:02:00.1 {
356                 |    num-rx-queues 2 
357                 |    num-tx-queues 2
358                 | }
359
360 * **vdev <eal-command>**
361     Provide a DPDK EAL command to specify bonded Ethernet interfaces, operating
362     modes and PCI addresses of slave links. Only XOR balanced (mode 2) mode is
363     supported.
364     
365     **Example:**
366
367                 | vdev eth_bond0,mode=2,slave=0000:0f:00.0,slave=0000:11:00.0,xmit_policy=l34
368                 | vdev eth_bond1,mode=2,slave=0000:10:00.0,slave=0000:12:00.0,xmit_policy=l34
369
370 * **num-mbufs <n>**
371     Increase number of buffers allocated. May be needed in scenarios with
372     large number of interfaces and worker threads, or a lot of physical
373     interfaces with multiple RSS queues. Value is per CPU socket. Default is
374     16384.
375     
376     **Example:** num-mbufs 128000
377
378 * **no-pci**
379     When VPP is started, if an interface is not owned by the linux kernel
380     (interface is administratively down), VPP will attempt to manage the
381     interface. *'no-pci'* indicates that VPP should not walk the PCI table
382     looking for interfaces.
383     
384     **Example:** no-pci
385
386 * **no-hugetlb**
387     Don't use huge TLB pages. Potentially useful for running simulator images.
388     
389     **Example:** no-hugetlb
390
391 * **kni <n>**
392     Number of KNI interfaces. Refer to the DPDK documentation.
393     
394     **Example:** kni 2
395
396 * **uio-driver uio_pci_generic|igb_uio|vfio-pci|auto**
397     Change UIO driver used by VPP. Default is *'auto'*.
398     
399     **Example:** uio-driver igb_uio
400
401 * **socket-mem <n>**
402     Change hugepages allocation per-socket, needed only if there is need for
403     larger number of mbufs. Default is 64 hugepages on each detected CPU
404     socket.
405     
406     **Example:** socket-mem 2048,2048
407
408**Other options include:**
409
410 * **enable-tcp-udp-checksum**
411     Enables UDP/TCP RX checksum offload.
412     
413     **Example:** enable-tcp-udp-checksum
414
415 * **no-multi-seg**
416     Disable multi-segment buffers, improves performance but disables Jumbo MTU
417     support.
418     
419     **Example:** no-multi-seg
420
421 * **no-tx-checksum-offload**
422     Disables UDP/TCP TX checksum offload. Typically needed for use faster
423     vector PMDs (together with no-multi-seg).
424     
425     **Example:** no-tx-checksum-offload
426
427 * **decimal-interface-names**
428     Format DPDK device names with decimal, as opposed to hexadecimal. 
429     
430     **Example:** decimal-interface-names
431
432 * **log-level  emergency|alert|critical|error|warning|notice|info|debug**
433     Set the log level for DPDK logs. Default is *'notice'*.
434     
435     **Example:** log-level error
436
437 * **dev default { .. }**
438     Change default settings for all interfaces. This sections supports the
439     same set of custom parameters described in *'dev <pci-dev> { .. }*'.
440     
441     **Example:**
442
443                 | dev default {
444                 |    num-rx-queues 3
445                 |    num-tx-queues 3
446                 | }
447
448.. _cpu:
449
450"cpu" Parameters
451________________
452
453Command-line CPU configuration controls the creation of named thread types, and
454the cpu affinity thereof. In the VPP there is one main thread and optionally
455the user can create worker(s). The main thread and worker thread(s) can be
456pinned to CPU core(s) automatically or manually.
457
458**Automatic Pinning:**
459
460 * **workers <n>**
461     Create <n> worker threads.
462     
463     **Example:** workers 4
464
465 * **io <n>**
466     Create <n> i/o threads.
467     
468     **Example:** io 2
469 
470 * **main-thread-io**
471     Handle i/o devices from thread 0, hand off traffic to worker threads.
472     Requires "workers <n>".
473     
474     **Example:** main-thread-io
475 
476 * **skip-cores <n>**
477     Sets number of CPU core(s) to be skipped (1 ... N-1). Skipped CPU core(s)
478     are not used for pinning main thread and working thread(s). The main thread
479     is automatically pinned to the first available CPU core and worker(s) are
480     pinned to next free CPU core(s) after core assigned to main threadLeave
481     the low nn bits of the process affinity mask clear.
482     
483     **Example:** skip-cores 4
484
485**Manual Pinning:**
486
487 * **main-core <n>**
488     Assign main thread to a specific core.
489     
490     **Example:** main-core 1
491     
492 * **coremask-workers <hex-mask>**
493     Place worker threads according to the bitmap hex-mask.
494     
495     **Example:** coremask-workers 0x0000000000C0000C
496     
497 * **corelist-workers <list>**
498     Same as coremask-workers but accepts a list of cores instead of a bitmap.
499     
500     **Example:** corelist-workers 2-3,18-19
501     
502 * **coremask-io <hex-mask>**
503     Place I/O threads according to the bitmap hex-mask.
504     
505     **Example:** coremask-io 0x0000000003000030
506     
507 * **corelist-io <list>**
508     Same as coremask-io but accepts a list of cores instead of a bitmap.
509     
510     **Example:** corelist-io 4-5,20-21
511     
512 * **coremask-hqos-threads <hex-mask>**
513     Place HQoS threads according to the bitmap hex-mask. A HQoS thread can
514     run multiple HQoS objects each associated with different output interfaces.
515     
516     **Example:** coremask-hqos-threads 0x000000000C0000C0
517
518 * **corelist-hqos-threads <list>**
519     Same as coremask-hqos-threads but accepts a list of cores instead of a
520     bitmap.
521     
522     **Example:** corelist-hqos-threads 6-7,22-23
523
524**Other:**
525
526 * **use-pthreads**
527     TBD
528     
529     **Example:** use-pthreads
530
531 * **thread-prefix <prefix>**
532     Set a prefix to be prepended to each thread name. The thread name already
533     contains an underscore. If not provided, the default is *'vpp'*.
534     Currently, prefix used on threads: *'vpp_main'*, *'vpp_stats'*
535     
536     **Example:** thread-prefix vpp1
537
538 * **scheduler-policy rr|fifo|batch|idle|other**
539     TBD
540     
541     **Example:** scheduler-policy fifo
542
543 * **scheduler-priority <n>**
544     Set the scheduler priority. Only valid if the *'scheduler-policy'* is set
545     to *'fifo'* or *'rr'*. The valid ranges for the scheduler priority depends
546     on the *'scheduler-policy'* and the current kernel version running. The
547     range is typically 1 to 99, but see the linux man pages for *'sched'* for
548     more details. If this value is not set, the current linux kernel default
549     is left in place.
550     
551     **Example:** scheduler-priority 50
552
553 * **<thread-name> <count>**
554     Set the number of threads for a given thread (by name). Some threads, like
555     *'stats'*, have a fixed number of threads and cannot be changed. List of
556     possible threads include (but not limited too): hqos-threads, workers
557     
558     **Example:** hqos-threads 2
559
560.. note::
561
562    The "main" thread always occupies the lowest core-id specified in the
563    DPDK [process-level] coremask.
564
565Here's a full-bore manual placement example:
566
567.. code-block:: console
568
569   /usr/bin/vpp  unix interactive tuntap disable cpu { main-thread-io coremask-workers 18 coremask-stats 4 } dpdk { coremask 1e }
570   
571   # taskset -a -p <vpe-pid>
572   pid 16251's current affinity mask: 2        # main thread
573   pid 16288's current affinity mask: ffffff   # DPDK interrupt thread (not bound to a core)
574   pid 16289's current affinity mask: 4        # stats thread
575   pid 16290's current affinity mask: 8        # worker thread 0
576   pid 16291's current affinity mask: 10       # worker thread 1
577
578
579.. _acl-plugin:
580
581"acl-plugin" Parameters
582_______________________
583
584These parameters change the configuration of the ACL (access control list) plugin,
585such as how the ACL bi-hash tables are initialized.
586
587They should only be set by those that are familiar with the interworkings of VPP
588and the ACL Plugin.
589
590The first three parameters, *connection hash buckets*, *connection hash memory*,
591and *connection count max*, set the **connection table per-interface parameters**
592for modifying how the two bounded-index extensible hash tables for
593IPv6 (40\*8 bit key and 8\*8 bit value pairs) and IPv4
594(16\*8 bit key and 8\*8 bit value pairs) **ACL plugin FA interface sessions**
595are initialized.
596
597 * **connection hash buckets <n>**
598     Sets the number of hash buckets (rounded up to a power of 2) in each
599     of the two bi-hash tables. Defaults to 64\*1024 (65536) hash buckets.
600     
601     **Example:** connection hash buckets 65536
602     
603 * **connection hash memory <n>**
604     Sets the allocated memory size (in bytes) for each of the two bi-hash tables.
605     Defaults to 1073741824 bytes.
606     
607     **Example:** connection hash memory 1073741824
608     
609 * **connection count max <n>**
610     Sets the maximum number of pool elements when allocating each per-worker
611     pool of sessions for both bi-hash tables. Defaults to 500000 elements in each pool.
612     
613     **Example:** connection count max 500000
614     
615 * **main heap size <n>G|<n>M|<n>K|<n>**
616     Sets the size of the main memory heap that holds all the ACL module related
617     allocations (other than hash.) Default size is 0, but during
618     ACL heap initialization is equal to
619     *per_worker_size_with_slack * tm->n_vlib_mains + bihash_size + main_slack*.
620     Note that these variables are partially based on the
621     **connection table per-interface parameters** mentioned above.
622     
623     **Example:** main heap size 3G
624
625The next three parameters, *hash lookup heap size*, *hash lookup hash buckets*,
626and *hash lookup hash memory*, modify the initialization of the bi-hash lookup
627table used by the ACL plugin. This table is initialized when attempting to apply
628an ACL to the existing vector of ACLs looked up during packet processing
629(but it is found that the table does not exist / has not been initialized yet.)
630     
631 * **hash lookup heap size  <n>G|<n>M|<n>K|<n>**
632     Sets the size of the memory heap that holds all the miscellaneous allocations
633     related to hash-based lookups. Default size is 67108864 bytes.
634     
635     **Example:** hash lookup heap size 70M
636     
637 * **hash lookup hash buckets <n>**
638     Sets the number of hash buckets (rounded up to a power of 2) in the bi-hash
639     lookup table. Defaults to 65536 hash buckets.
640     
641     **Example:** hash lookup hash buckets 65536
642     
643 * **hash lookup hash memory <n>**
644     Sets the allocated memory size (in bytes) for the bi-hash lookup table.
645     Defaults to 67108864 bytes.
646     
647     **Example:** hash lookup hash memory 67108864
648     
649 * **use tuple merge <n>**
650     Sets a boolean value indicating whether or not to use TupleMerge
651     for hash ACL's. Defaults to 1 (true), meaning the default implementation
652     of hashing ACL's **does use** TupleMerge.
653     
654     **Example:** use tuple merge 1
655     
656 * **tuple merge split threshold <n>**
657     Sets the maximum amount of rules (ACE's) that can collide in a bi-hash
658     lookup table before the table is split into two new tables. Splitting ensures
659     less rule collisions by hashing colliding rules based on their common tuple
660     (usually their maximum common tuple.) Splitting occurs when the
661     *length of the colliding rules vector* is greater than this threshold amount.
662     Defaults to a maximum of 39 rule collisions per table.
663     
664     **Example:** tuple merge split threshold 30
665     
666 * **reclassify sessions <n>**
667     Sets a boolean value indicating whether or not to take the epoch of the session
668     into account when dealing with re-applying ACL's or changing already applied ACL's.
669     Defaults to 0 (false), meaning the default implementation **does NOT** take the
670     epoch of the session into account.
671     
672     **Example:** reclassify sessions 1
673
674.. _api-queue:
675
676"api-queue" Parameters
677______________________
678
679The following parameters should only be set by those that are familiar with the
680interworkings of VPP.
681
682 * **length  <n>**
683     Sets the api queue length. Minimum valid queue length is 1024, which is
684     also the default.
685     
686     **Example:** length 2048
687
688.. _api-segment:
689
690"api-segment" Parameters
691________________________
692
693These values control various aspects of the binary API interface to VPP.
694
695 * **prefix <path>**
696     Sets the prefix prepended to the name used for shared memory (SHM)
697     segments. The default is empty, meaning shared memory segments are created
698     directly in the SHM directory *'/dev/shm'*. It is worth noting that on
699     many systems *'/dev/shm'* is a symbolic link to somewhere else in the file
700     system; Ubuntu links it to *'/run/shm'*.
701     
702     **Example:** prefix /run/shm
703
704 * **uid <number|name>**
705     Sets the user ID or name that should be used to set the ownership of the
706     shared memory segments. Defaults to the same user that VPP is started
707     with, probably root.
708
709     **Example:** uid root
710
711 * **gid <number|name>**
712     Sets the group ID or name that should be used to set the ownership of the
713     shared memory segments. Defaults to the same group that VPP is started
714     with, probably root.
715     
716     **Example:** gid vpp
717
718The following parameters should only be set by those that are familiar with the
719interworkings of VPP.
720
721 * **baseva <x>**
722     Set the base address for SVM global region. If not set, on AArch64, the
723     code will try to determine the base address. All other default to
724     0x30000000.
725     
726     **Example:** baseva 0x20000000
727
728 * **global-size <n>G|<n>M|<n>**
729     Set the global memory size, memory shared across all router instances,
730     packet buffers, etc. If not set, defaults to 64M. The input value can be
731     set in GB, MB or bytes.
732     
733     **Example:** global-size 2G
734
735 * **global-pvt-heap-size <n>M|size <n>**
736     Set the size of the global VM private mheap. If not set, defaults to 128k.
737     The input value can be set in MB or bytes.
738     
739     **Example:** global-pvt-heap-size size 262144
740
741 * **api-pvt-heap-size <n>M|size <n>**
742     Set the size of the api private mheap. If not set, defaults to 128k.
743     The input value can be set in MB or bytes.
744     
745     **Example:** api-pvt-heap-size 1M
746
747 * **api-size <n>M|<n>G|<n>**
748     Set the size of the API region. If not set, defaults to 16M. The input
749     value can be set in GB, MB or bytes.
750     
751     **Example:** api-size 64M
752
753.. _api-trace:
754
755"api-trace" Parameters
756______________________
757
758The ability to trace, dump, and replay control-plane API traces makes all the
759difference in the world when trying to understand what the control-plane has
760tried to ask the forwarding-plane to do.
761
762 * **on|enable**
763     Enable API trace capture from the beginning of time, and arrange for a
764     post-mortem dump of the API trace if the application terminates abnormally.
765     By default, the (circular) trace buffer will be configured to capture
766     256K traces. The default *'startup.conf'* file has trace enabled by default,
767     and unless there is a very strong reason, it should remain enabled.
768     
769     **Example:** on
770
771 * **nitems <n>**
772     Configure the circular trace buffer to contain the last <n> entries. By
773     default, the trace buffer captures the last 256K API messages received.
774     
775     **Example:** nitems 524288
776
777 * **save-api-table <filename>**
778     Dumps the API message table to /tmp/<filename>.
779     
780     **Example:** save-api-table apiTrace-07-04.txt
781
782Typically, one simply enables the API message trace scheme:
783
784     api-trace { on }
785
786.. _buffers:
787
788"buffers" Parameters
789____________________
790
791Command line Buffer configuration controls buffer management.
792
793 * **memory-size-in-mb <n>**
794     Configure the memory size used for buffers. If not set, VPP defaults
795     to 32MB.
796     
797     **Example:** memory-size-in-mb 64
798
799
800.. _cj:
801
802"cj" Parameters
803_______________
804
805The circular journal (CJ) thread-safe circular log buffer scheme is
806occasionally useful when chasing bugs. Calls to it should not be checked in.
807See .../vlib/vlib/unix/cj.c. The circular journal is disables by default.
808When enabled, the number of records must be provided, there is no default
809value.
810
811 * **records <n>**
812     Configure the number of circular journal records in the circular buffer.
813     The number of records should be a power of 2.
814     
815     **Example:** records 131072
816
817 * **on**
818     Turns on logging at the earliest possible moment.
819     
820     **Example:** on
821
822.. _dns:
823
824"dns" Parameters
825________________
826
827 * **max-cache-size <n>**
828     Set the maximum number of active elements allowed in the pool of
829     dns cache entries. When resolving an expired entry or adding a new
830     static entry and the max number of active entries is reached,
831     a random, non-static entry is deleted. Defaults to 65535 entries.
832     
833     **Example:** max-cache-size 65535
834     
835 * **max-ttl <n>**
836     Currently not implemented. Defaults to 86400 seconds (24 hours.)
837     
838     **Example:** max-ttl 86400
839
840.. _heapsize:
841
842"heapsize" Parameters
843_____________________
844
845Heapsize configuration controls the size of the main heap. The heap size is
846configured very early in the boot sequence, before loading plug-ins or doing
847much of anything else.
848
849 * **heapsize <n>M|<n>G**
850     Specifies the size of the heap in MB or GB. The default is 1GB. Setting the
851     main heap size to 4GB or more requires recompilation of the entire system
852     with CLIB_VEC64 > 0. See .../clib/clib/vec_bootstrap.h.
853     
854     **Example:** heapsize 2G
855
856.. _ip:
857
858"ip" Parameters
859_______________
860
861IPv4 heap configuration. he heap size is configured very early in the boot
862sequence, before loading plug-ins or doing much of anything else.
863
864 * **heap-size <n>G|<n>M|<n>K|<n>**
865     Set the IPv4 mtrie heap size, which is the amount of memory dedicated to
866     the destination IP lookup table. The input value can be set in GB, MB, KB
867     or bytes. The default value is 32MB.
868     
869     **Example:** heap-size 64M
870
871.. _ip6:
872
873"ip6" Parameters
874________________
875
876IPv6 heap configuration. he heap size is configured very early in the boot
877sequence, before loading plug-ins or doing much of anything else.
878
879
880 * **heap-size <n>G|<n>M|<n>K|<n>**
881     Set the IPv6 forwarding table heap size. The input value can be set in GB,
882     MB, KB or bytes. The default value is 32MB.
883     
884     **Example:** heap-size 64M
885     
886 * **hash-buckets <n>**
887     Set the number of IPv6 forwarding table hash buckets. The default value is
888     64K (65536).
889     
890     **Example:** hash-buckets 131072
891
892.. _l2learn:
893
894"l2learn" Parameters
895____________________
896
897Configure Layer 2 MAC Address learning parameters.
898
899 * **limit <n>**
900     Configures the number of L2 (MAC) addresses in the L2 FIB at any one time,
901     which limits the size of the L2 FIB to <n> concurrent entries.  Defaults to
902     4M entries (4194304).
903     
904     **Example:** limit 8388608
905
906.. _l2tp:
907
908"l2tp" Parameters
909_________________
910
911IPv6 Layer 2 Tunnelling Protocol Version 3 (IPv6-L2TPv3) configuration controls
912the method used to locate a specific IPv6-L2TPv3 tunnel. The following settings
913are mutually exclusive:
914
915 * **lookup-v6-src**
916     Lookup tunnel by IPv6 source address.
917     
918     **Example:** lookup-v6-src
919     
920 * **lookup-v6-dst**
921     Lookup tunnel by IPv6 destination address.
922     
923     **Example:** lookup-v6-dst
924     
925 * **lookup-session-id**
926     Lookup tunnel by L2TPv3 session identifier.
927     
928     **Example:** lookup-session-id
929
930.. _logging:
931
932"logging" Parameters
933____________________
934
935 * **size <n>**
936     Number of entries in the global logging buffer. Defaults to 512.
937     
938     **Example:** size 512
939     
940 * **unthrottle-time <n>**
941     Set the global value for the time to wait (in seconds) before resuming logging of a log subclass that exceeded the per-subclass message-per-second threshold.  Defaults to 3.
942     
943     **Example:** unthrottle-time 3
944     
945 * **default-log-level emerg|alert|crit|err|warn|notice|info|debug|disabled**
946     Set the default logging level of the system log.  Defaults to notice.
947     
948     **Example:** default-log-level notice
949     
950 * **default-syslog-log-level emerg|alert|crit|err|warn|notice|info|debug|disabled**
951     Set the default logging level of the syslog target.  Defaults to warning.
952     
953     **Example:** default-syslog-log-level warning
954
955.. _mactime:
956
957"mactime" Parameters
958____________________
959
960 * **lookup-table-buckets <n>**
961     Sets the number of hash buckets in the mactime bi-hash lookup table.
962     Defaults to 128 buckets.
963     
964     **Example:** lookup-table-buckets 128
965     
966 * **lookup-table-memory <n>G|<n>M|<n>K|<n>**
967     Sets the allocated memory size (in bytes) for the mactime bi-hash lookup table.
968     The input value can be set in GB, MB, KB or bytes. The default value is 262144
969     (256 << 10) bytes or roughly 256KB.
970     
971     **Example:** lookup-table-memory 300K
972     
973 * **timezone_offset <n>**
974     Sets the timezone offset from UTC. Defaults to an offset of -5 hours
975     from UTC (US EST / EDT.)
976     
977     **Example:** timezone_offset -5
978
979.. _map:
980
981"map" Parameters
982________________
983
984 * **customer edge**
985     Sets a boolean true to indicate that the MAP node is a Customer Edge (CE)
986     router. The boolean defaults to false, meaning the MAP node is not treated
987     as a CE router.
988     
989     **Example:** customer edge
990
991.. _mc:
992
993"mc" Parameters
994_______________
995
996MC Test Process.
997
998 * **interface <name>**
999     TBD
1000     
1001     **Example:** TBD
1002     
1003 * **n-bytes <n>**
1004     TBD
1005     
1006     **Example:** TBD
1007     
1008 * **max-n-bytes <n>**
1009     TBD
1010     
1011     **Example:** TBD
1012     
1013 * **min-n-bytes <n>**
1014     TBD
1015     
1016     **Example:** TBD
1017     
1018 * **seed <n>**
1019     TBD
1020     
1021     **Example:** TBD
1022     
1023 * **window <n>**
1024     TBD
1025     
1026     **Example:** TBD
1027     
1028 * **verbose**
1029     TBD
1030     
1031     **Example:** verbose
1032     
1033 * **no-validate**
1034     TBD
1035     
1036     **Example:** no-validate
1037     
1038 * **min-delay <n.n>**
1039     TBD
1040     
1041     **Example:** TBD
1042     
1043 * **max-delay <n.n>**
1044     TBD
1045     
1046     **Example:** TBD
1047     
1048 * **no-delay**
1049     TBD
1050     
1051     **Example:** no-delay
1052     
1053 * **n-packets <n.n>**
1054     TBD
1055     
1056     **Example:** TBD
1057
1058.. _nat:
1059
1060
1061"nat" Parameters
1062________________
1063
1064These parameters change the configuration of the NAT (Network address translation)
1065plugin, such as how the NAT & NAT64 bi-hash tables are initialized, if the NAT is
1066endpoint dependent, or if the NAT is deterministic.
1067
1068For each NAT per thread data, the following 4 parameters change how certain
1069bi-hash tables are initialized.
1070
1071 * **translation hash buckets <n>**
1072     Sets the number of hash buckets in each of the two in/out NAT bi-hash lookup
1073     tables. Defaults to 1024 buckets.
1074
1075     If the NAT is indicated to be endpoint dependent, which can be set with the
1076     :ref:`endpoint-dependent parameter <endpointLabel>`, then this parameter sets
1077     the number of hash buckets in each of the two endpoint dependent sessions
1078     NAT bi-hash lookup tables.
1079     
1080     **Example:** translation hash buckets 1024
1081     
1082 * **translation hash memory <n>**
1083     Sets the allocated memory size (in bytes) for each of the two in/out NAT
1084     bi-hash tables. Defaults to 134217728 (128 << 20) bytes, which is roughly 128 MB.
1085
1086     If the NAT is indicated to be endpoint dependent, which can be set with the
1087     :ref:`endpoint-dependent parameter <endpointLabel>`, then this parameter sets the
1088     allocated memory size for each of the two endpoint dependent sessions NAT bi-hash
1089     lookup tables.
1090     
1091     **Example:** translation hash memory 134217728
1092     
1093 * **user hash buckets <n>**
1094     Sets the number of hash buckets in the user bi-hash lookup table
1095     (src address lookup for a user.) Defaults to 128 buckets.
1096     
1097     **Example:** user hash buckets 128
1098     
1099 * **user hash memory <n>**
1100     Sets the allocated memory size (in bytes) for the user bi-hash lookup table
1101     (src address lookup for a user.) Defaults to 67108864 (64 << 20) bytes,
1102     which is roughly 64 MB.
1103     
1104     **Example:** user hash memory 67108864
1105     
1106 * **max translations per user <n>**
1107     Sets the maximum amount of dynamic and/or static NAT sessions each user can have.
1108     Defaults to 100. When this limit is reached, the least recently used translation
1109     is recycled.
1110     
1111     **Example:** max translations per user 50
1112     
1113 * **outside VRF id <n>**
1114     TBD
1115     
1116     **Example:** TBD
1117     
1118 * **outside ip6 VRF id <n>**
1119     TBD
1120     
1121     **Example:** TBD
1122     
1123 * **inside VRF id <n>**
1124     TBD
1125     
1126     **Example:** TBD
1127     
1128 * **inside VRF id <n>**
1129     TBD
1130     
1131     **Example:** TBD
1132     
1133 * **static mapping only**
1134     TBD
1135     
1136     **Example:** static mapping only
1137     
1138 * **connection tracking**
1139     TBD
1140     
1141     **Example:** connection tracking
1142     
1143 * **deterministic**
1144     Sets a boolean value to 1 indicating that the NAT is deterministic. Defaults to 0,
1145     meaning the NAT is not deterministic.
1146     
1147     **Example:** deterministic
1148     
1149 * **nat64 bib hash buckets <n>**
1150     Sets the number of hash buckets in each of the two in/out NAT64 BIB bi-hash
1151     tables. Defaults to 1024 buckets.
1152     
1153     **Example:** nat64 bib hash buckets 1024
1154     
1155 * **nat64 bib hash memory <n>**
1156     Sets the allocated memory size (in bytes) for each of the two in/out NAT64
1157     BIB bi-hash tables. Defaults to 134217728 (128 << 20) bytes,
1158     which is roughly 128 MB.
1159     
1160     **Example:** nat64 bib hash memory 134217728
1161     
1162 * **nat64 st hash buckets <n>**
1163     Sets the number of hash buckets in each of the two in/out NAT64 session table
1164     bi-hash tables. Defaults to 2048 buckets.
1165     
1166     **Example:** nat64 st hash buckets 2048
1167     
1168 * **nat64 st hash memory <n>**
1169     Sets the allocated memory size (in bytes) for each of the two in/out NAT64 session
1170     table bi-hash tables. Defaults to 268435456 (256 << 20) bytes, which is roughly
1171     256 MB.
1172     
1173     **Example:** nat64 st hash memory 268435456
1174     
1175 * **out2in dpo**
1176     TBD
1177     
1178     **Example:** out2in dpo
1179     
1180 * **dslite ce**
1181     TBD
1182     
1183     **Example:** dslite ce
1184     
1185.. _endpointLabel:
1186
1187 * **endpoint-dependent**
1188     Sets a boolean value to 1, indicating that the NAT is endpoint dependent.
1189     Defaults to 0, meaning the NAT is not endpoint dependent.
1190     
1191     **Example:** endpoint-dependent
1192
1193.. _oam:
1194
1195"oam" Parameters
1196________________
1197
1198OAM configuration controls the (ip4-icmp) interval, and number of misses
1199allowed before reporting an oam target down to any registered listener.
1200
1201 * **interval <n.n>**
1202     Interval, floating-point seconds, between sending OAM IPv4 ICMP messages.
1203     Default is 2.04 seconds.
1204     
1205     **Example:** interval 3.5
1206     
1207 * **misses-allowed <n>**
1208     Number of misses before declaring an OAM target down. Default is 3 misses.
1209     
1210     **Example:** misses-allowed 5
1211
1212.. _plugins:
1213
1214"plugins" Parameters
1215____________________
1216
1217A plugin can be disabled by default. It may still be in an experimental phase
1218or only be needed in special circumstances. If this is the case, the plugin can
1219be explicitly enabled in *'startup.conf'*. Also, a plugin that is enabled by
1220default can be explicitly disabled in *'startup.conf'*.
1221
1222Another useful use of this section is to disable all the plugins, then enable
1223only the plugins that are desired.
1224
1225 * **path <path>**
1226     Adjust the plugin path depending on where the VPP plugins are installed.
1227     
1228     **Example:** path /home/bms/vpp/build-root/install-vpp-native/vpp/lib/vpp_plugins
1229     
1230 * **name-filter <filter-name>**
1231     TBD
1232     
1233     **Example:** TBD
1234     
1235 * **vat-path <path>**
1236     TBD
1237     
1238     **Example:** TBD
1239     
1240 * **vat-name-filter <filter-name>**
1241     TBD
1242     
1243     **Example:** TBD
1244     
1245 * **plugin <plugin.so> { .. }**
1246     Configure parameters for a given plugin. Valid parameters are as follows: 
1247
1248      * **enable**
1249          Enable the given plugin.
1250      * **disable**
1251          Disable the given plugin.
1252      * **skip-version-check**
1253          In the plugin registration, if *'.version_required'* is set, the
1254          plugin will not be loaded if there is version mismatch between
1255          plugin and VPP. This can be bypassed by setting "skip-version-check"
1256          for specific plugin.
1257     
1258     **Example:** plugin ila_plugin.so { enable skip-version-check }
1259     
1260 * **plugin default { .. }**
1261     Set the default behavior for all plugins. Valid parameters are as follows:
1262     
1263       * **disable**
1264          Disable all plugins.
1265     
1266     **Example:**
1267               | plugin default { disable }
1268               | plugin dpdk_plugin.so { enable }
1269               | plugin acl_plugin.so { enable }
1270
1271.. _plugin_path:
1272
1273"plugin_path" Parameters
1274________________________
1275
1276Alternate syntax to choose plugin path. Plugin_path configuration controls the
1277set of directories searched for vlib plugins. Supply a colon-separated list of
1278(absolute) directory names: plugin_path dir1:dir2:...:dirN
1279
1280    **Example:** plugin_path /home/bms/vpp/build-root/install-vpp-native/vpp/lib/vpp_plugins
1281
1282.. _punt:
1283
1284"punt" Parameters
1285_________________
1286
1287Configuration parameters for the local TCP/IP stack punt infrastructure.
1288
1289 * **socket <path>**
1290     The filesystem pathname of a bound UNIX domain socket to be used with punt.
1291     
1292     **Example:** TBD
1293
1294.. _session:
1295
1296"session" Parameters
1297____________________
1298
1299 * **event-queue-length <n>**
1300     TBD
1301     
1302     **Example:** TBD
1303     
1304 * **preallocated-sessions <n>**
1305     TBD
1306     
1307     **Example:** TBD
1308     
1309 * **v4-session-table-buckets <n>**
1310     TBD
1311     
1312     **Example:** TBD
1313     
1314 * **v4-halfopen-table-buckets <n>**
1315     TBD
1316     
1317     **Example:** TBD
1318     
1319 * **v6-session-table-buckets <n>**
1320     TBD
1321     
1322     **Example:** TBD
1323     
1324 * **v6-halfopen-table-buckets <n>**
1325     TBD
1326     
1327     **Example:** TBD
1328     
1329 * **v4-session-table-memory <n>G|<n>M|<n>K|<n>**
1330     TBD
1331     The input value can be set in GB, MB, KB or bytes.
1332     
1333     **Example:** TBD
1334     
1335 * **v4-halfopen-table-memory <n>G|<n>M|<n>K|<n>**
1336     TBD
1337     The input value can be set in GB, MB, KB or bytes.
1338     
1339     **Example:** TBD
1340     
1341 * **v6-session-table-memory <n>G|<n>M|<n>K|<n>**
1342     TBD
1343     The input value can be set in GB, MB, KB or bytes.
1344     
1345     **Example:** TBD
1346     
1347 * **v6-halfopen-table-memory <n>G|<n>M|<n>K|<n>**
1348     TBD
1349     The input value can be set in GB, MB, KB or bytes.
1350     
1351     **Example:** TBD
1352     
1353 * **local-endpoints-table-memory <n>G|<n>M|<n>K|<n>**
1354     TBD
1355     The input value can be set in GB, MB, KB or bytes.
1356     
1357     **Example:** TBD
1358     
1359 * **local-endpoints-table-buckets <n>**
1360     TBD
1361     
1362     **Example:** TBD
1363     
1364 * **evt_qs_memfd_seg**
1365     TBD
1366     
1367     **Example:** evt_qs_memfd_seg
1368
1369.. _socketsvr:
1370
1371"socketsvr" Parameters
1372______________________
1373
1374Create a socket server for API server (.../vlibmemory/socksvr_vlib.c.).
1375If not set, API server doesn't run.
1376
1377 * **socket-name <filename>**
1378     Configure API socket filename.
1379     
1380     **Example:** socket-name /run/vpp/api.sock
1381     
1382 * **default**
1383     Use the default API socket (/run/api.sock).
1384     
1385     **Example:** default
1386
1387.. _stats:
1388
1389"stats" Parameters
1390__________________
1391
1392Create a socket server for *'stats'* poller. If not set, 'stats'* poller
1393doesn't run.
1394
1395 * **socket-name <filename>**
1396     Configure *'stats'* socket filename.
1397     
1398     **Example:** socket-name /run/vpp/stats.sock
1399     
1400 * **default**
1401     Use the default *'stats'* socket (/run/vpp/stats.sock).
1402     
1403     **Example:** default
1404
1405.. _statseg:
1406
1407"statseg" Parameters
1408____________________
1409
1410 * **size <n>G|<n>M|<n>K|<n>**
1411     Sets the size of the memory mapped stats segment object *stat_segment*.
1412     The input value can be set in GB, MB, KB or bytes. Defaults to 33554432
1413     (32 << 20) bytes or roughly 32 MB.
1414     
1415     **Example:** size 32M
1416     
1417.. _tapcli:     
1418
1419"tapcli" Parameters
1420___________________
1421
1422Configuration parameters for TAPCLI (dynamic tap interface hookup.)
1423
1424 * **mtu <n>**
1425     Sets interface MTU (maximum transmission unit) size in bytes. This size
1426     is also related to the number of MTU buffers. Defaults to 1500 bytes.
1427     
1428     **Example:** mtu 1500
1429     
1430 * **disable**
1431     Disables TAPCLI. Default is that TAPCLI is enabled.
1432     
1433     **Example:** disable
1434
1435.. _tcp:
1436
1437"tcp" Parameters
1438________________
1439
1440Configuration parameters for TCP host stack utilities. The following
1441preallocation parameters are related to the initialization of fixed-size,
1442preallocation pools.
1443
1444 * **preallocated-connections <n>**
1445     Sets the number of preallocated TCP connections. Defaults to 0.
1446     The preallocated connections per thread is related to this value,
1447     equal to (preallocated_connections / (num_threads - 1)).
1448     
1449     **Example:** preallocated-connections 5
1450     
1451 * **preallocated-half-open-connections <n>**
1452     Sets the number of preallocated TCP half-open connections. Defaults to 0.
1453     
1454     **Example:** preallocated-half-open-connections 5
1455     
1456 * **buffer-fail-fraction <n.n>**
1457     Sets the TCP buffer fail fraction (a float) used for fault-injection
1458     when debugging TCP buffer allocation. Its use is found in *tcp_debug.h*.
1459     Defaults to 0.0.
1460     
1461     **Example:** buffer-fail-fraction 0.0
1462
1463.. _tls:
1464
1465"tls" Parameters
1466________________
1467
1468Configures TLS parameters, such as enabling the use of test certificates.
1469These parameters affect the tlsmbedtls and tlsopenssl plugins.
1470
1471 * **use-test-cert-in-ca**
1472     Sets a boolean value to 1 to indicate during the initialization of a
1473     TLS CA chain to attempt to parse and add test certificates to the chain.
1474     Defaults to 0, meaning test certificates are not used.
1475     
1476     **Example:** use-test-cert-in-ca
1477     
1478 * **ca-cert-path <filename>**
1479     Sets the filename path of the location of TLS CA certificates, used when
1480     initializing and loading TLS CA certificates during the initialization
1481     of a TLS CA chain. If not set, the default filename path is
1482     */etc/ssl/certs/ca-certificates.crt*.
1483     
1484     **Example:** ca-cert-path /etc/ssl/certs/ca-certificates.crt
1485
1486.. _tuntap:
1487
1488"tuntap" Parameters
1489___________________
1490
1491The "tuntap" driver configures a point-to-point interface between the vpp
1492engine and the local Linux kernel stack. This allows e.g. users to ssh to the
1493host | VM | container via vpp "revenue" interfaces. It's marginally useful, and
1494is currently disabled by default. To [dynamically] create TAP interfaces - the
1495preferred scheme - see the "tap_connect" binary API. The Linux network stack
1496"vnet" interface needs to manually configure, and VLAN and other settings if
1497desired.
1498
1499 * **enable|disable**
1500     Enable or disable the tun/tap driver. 
1501     
1502     **Example:** enable
1503     
1504 * **ethernet|ether**
1505     Create a tap device (ethernet MAC) instead of a tun device (point-to-point
1506     tunnel). The two keywords are aliases for the same function.
1507     
1508     **Example:** ethernet
1509     
1510 * **have-normal-interface|have-normal**
1511     Treat the host Linux stack as a routing peer instead of programming VPP
1512     interface L3 addresses onto the tun/tap devices. The two keywords are
1513     aliases for the same function.
1514     
1515     **Example:** have-normal-interface
1516     
1517 * **name <name>**
1518     Assign name to the tun/tap device.
1519     
1520     **Example:** name vpp1
1521
1522Here's a typical multiple parameter invocation:
1523
1524     | tuntap { ethernet have-normal-interface name vpp1 }
1525
1526.. _vhost-user:
1527
1528"vhost-user" Parameters
1529_______________________
1530
1531Vhost-user configuration parameters control the vhost-user driver.
1532
1533 * **coalesce-frames <n>**
1534     Subject to deadline-timer expiration - see next item - attempt to transmit
1535     at least <n> packet frames. Default is 32 frames.
1536     
1537     **Example:** coalesce-frames 64
1538     
1539 * **coalesce-time <seconds>**
1540     Hold packets no longer than (floating-point) seconds before transmitting
1541     them. Default is 0.001 seconds
1542     
1543     **Example:** coalesce-time 0.002
1544     
1545 * **dont-dump-memory**
1546     vhost-user shared-memory segments can add up to a large amount of memory, so
1547     it's handy to avoid adding them to corefiles when using a significant number
1548     of such interfaces.
1549     
1550     **Example:** dont-dump-memory
1551
1552.. _vlib:
1553
1554"vlib" Parameters
1555_________________
1556
1557These parameters configure VLIB, such as allowing you to choose whether to
1558enable memory traceback or a post-mortem elog dump.
1559
1560 * **memory-trace**
1561     Enables memory trace (mheap traceback.) Defaults to 0, meaning memory
1562     trace is disabled.
1563     
1564     **Example:** memory-trace
1565     
1566 * **elog-events <n>**
1567     Sets the number of elements/events (the size) of the event ring
1568     (a circular buffer of events.) This number rounds to a power of 2.
1569     Defaults to 131072 (128 << 10) elements.
1570     
1571     **Example:** elog-events 4096
1572     
1573 * **elog-post-mortem-dump**
1574     Enables the attempt of a post-mortem elog dump to
1575     */tmp/elog_post_mortem.<PID_OF_CALLING_PROCESS>* if os_panic or
1576     os_exit is called.
1577     
1578     **Example:** elog-post-mortem-dump
1579 
1580