2 .. _performance_test_methodology:
4 Performance Test Methodology
5 ============================
10 Packet and bandwidth throughput are measured in accordance with
11 :rfc:`2544`, using FD.io CSIT Multiple Loss Ratio search (MLRsearch), an
12 optimized binary search algorithm, that measures SUT/DUT throughput at
13 different Packet Loss Ratio (PLR) values.
15 Following MLRsearch values are measured across a range of L2 frame sizes
18 - **Non Drop Rate (NDR)**: packet and bandwidth throughput at PLR=0%.
20 - **Aggregate packet rate**: NDR_LOWER <bi-directional packet rate>
22 - **Aggregate bandwidth rate**: NDR_LOWER <bi-directional bandwidth
25 - **Partial Drop Rate (PDR)**: packet and bandwidth throughput at
28 - **Aggregate packet rate**: PDR_LOWER <bi-directional packet rate>
30 - **Aggregate bandwidth rate**: PDR_LOWER <bi-directional bandwidth
33 NDR and PDR are measured for the following L2 frame sizes (untagged
36 - IPv4 payload: 64B, IMIX_v4_1 (28x64B, 16x570B, 4x1518B), 1518B, 9000B.
37 - IPv6 payload: 78B, 1518B, 9000B.
39 All rates are reported from external Traffic Generator perspective.
41 .. _mlrsearch_algorithm:
46 Multiple Loss Rate search (MLRsearch) is a new search algorithm
47 implemented in FD.io CSIT project. MLRsearch discovers multiple packet
48 throughput rates in a single search, with each rate associated with a
49 distinct Packet Loss Ratio (PLR) criteria.
51 Two throughput measurements used in FD.io CSIT are Non-Drop Rate (NDR,
52 with zero packet loss, PLR=0) and Partial Drop Rate (PDR, with packet
53 loss rate not greater than the configured non-zero PLR). MLRsearch
54 discovers NDR and PDR in a single pass reducing required execution time
55 compared to separate binary searches for NDR and PDR. MLRsearch reduces
56 execution time even further by relying on shorter trial durations
57 of intermediate steps, with only the final measurements
58 conducted at the specified final trial duration.
59 This results in the shorter overall search
60 execution time when compared to a standard NDR/PDR binary search,
61 while guaranteeing the same or similar results.
63 If needed, MLRsearch can be easily adopted to discover more throughput rates
64 with different pre-defined PLRs.
66 .. Note:: All throughput rates are *always* bi-directional
67 aggregates of two equal (symmetric) uni-directional packet rates
68 received and reported by an external traffic generator.
73 The main properties of MLRsearch:
75 - MLRsearch is a duration aware multi-phase multi-rate search algorithm.
77 - Initial phase determines promising starting interval for the search.
78 - Intermediate phases progress towards defined final search criteria.
79 - Final phase executes measurements according to the final search
84 - Uses link rate as a starting transmit rate and discovers the Maximum
85 Receive Rate (MRR) used as an input to the first intermediate phase.
87 - *Intermediate phases*:
89 - Start with initial trial duration (in the first phase) and converge
90 geometrically towards the final trial duration (in the final phase).
91 - Track two values for NDR and two for PDR.
93 - The values are called (NDR or PDR) lower_bound and upper_bound.
94 - Each value comes from a specific trial measurement
95 (most recent for that transmit rate),
96 and as such the value is associated with that measurement's duration and loss.
97 - A bound can be invalid, for example if NDR lower_bound
98 has been measured with nonzero loss.
99 - Invalid bounds are not real boundaries for the searched value,
100 but are needed to track interval widths.
101 - Valid bounds are real boundaries for the searched value.
102 - Each non-initial phase ends with all bounds valid.
104 - Start with a large (lower_bound, upper_bound) interval width and
105 geometrically converge towards the width goal (measurement resolution)
106 of the phase. Each phase halves the previous width goal.
107 - Use internal and external searches:
109 - External search - measures at transmit rates outside the (lower_bound,
110 upper_bound) interval. Activated when a bound is invalid,
111 to search for a new valid bound by doubling the interval width.
112 It is a variant of `exponential search`_.
113 - Internal search - `binary search`_, measures at transmit rates within the
114 (lower_bound, upper_bound) valid interval, halving the interval width.
116 - *Final phase* is executed with the final test trial duration, and the final
117 width goal that determines resolution of the overall search.
118 Intermediate phases together with the final phase are called non-initial phases.
120 The main benefits of MLRsearch vs. binary search include:
122 - In general MLRsearch is likely to execute more search trials overall, but
123 less trials at a set final duration.
124 - In well behaving cases it greatly reduces (>50%) the overall duration
125 compared to a single PDR (or NDR) binary search duration,
126 while finding multiple drop rates.
127 - In all cases MLRsearch yields the same or similar results to binary search.
128 - Note: both binary search and MLRsearch are susceptible to reporting
129 non-repeatable results across multiple runs for very bad behaving
134 - Worst case MLRsearch can take longer than a binary search e.g. in case of
135 drastic changes in behaviour for trials at varying durations.
137 Search Implementation
138 ~~~~~~~~~~~~~~~~~~~~~
140 Following is a brief description of the current MLRsearch
141 implementation in FD.io CSIT.
146 #. *maximum_transmit_rate* - maximum packet transmit rate to be used by
147 external traffic generator, limited by either the actual Ethernet
148 link rate or traffic generator NIC model capabilities. Sample
149 defaults: 2 * 14.88 Mpps for 64B 10GE link rate,
150 2 * 18.75 Mpps for 64B 40GE NIC maximum rate.
151 #. *minimum_transmit_rate* - minimum packet transmit rate to be used for
152 measurements. MLRsearch fails if lower transmit rate needs to be
153 used to meet search criteria. Default: 2 * 10 kpps (could be higher).
154 #. *final_trial_duration* - required trial duration for final rate
155 measurements. Default: 30 sec.
156 #. *initial_trial_duration* - trial duration for initial MLRsearch phase.
158 #. *final_relative_width* - required measurement resolution expressed as
159 (lower_bound, upper_bound) interval width relative to upper_bound.
161 #. *packet_loss_ratio* - maximum acceptable PLR search criteria for
162 PDR measurements. Default: 0.5%.
163 #. *number_of_intermediate_phases* - number of phases between the initial
164 phase and the final phase. Impacts the overall MLRsearch duration.
165 Less phases are required for well behaving cases, more phases
166 may be needed to reduce the overall search duration for worse behaving cases.
167 Default (2). (Value chosen based on limited experimentation to date.
168 More experimentation needed to arrive to clearer guidelines.)
173 1. First trial measures at maximum rate and discovers MRR.
175 a. *in*: trial_duration = initial_trial_duration.
176 b. *in*: offered_transmit_rate = maximum_transmit_rate.
177 c. *do*: single trial.
178 d. *out*: measured loss ratio.
179 e. *out*: mrr = measured receive rate.
181 2. Second trial measures at MRR and discovers MRR2.
183 a. *in*: trial_duration = initial_trial_duration.
184 b. *in*: offered_transmit_rate = MRR.
185 c. *do*: single trial.
186 d. *out*: measured loss ratio.
187 e. *out*: mrr2 = measured receive rate.
189 3. Third trial measures at MRR2.
191 a. *in*: trial_duration = initial_trial_duration.
192 b. *in*: offered_transmit_rate = MRR2.
193 c. *do*: single trial.
194 d. *out*: measured loss ratio.
201 a. *in*: trial_duration for the current phase.
202 Set to initial_trial_duration for the first intermediate phase;
203 to final_trial_duration for the final phase;
204 or to the element of interpolating geometric sequence
205 for other intermediate phases.
206 For example with two intermediate phases, trial_duration
207 of the second intermediate phase is the geometric average
208 of initial_strial_duration and final_trial_duration.
209 b. *in*: relative_width_goal for the current phase.
210 Set to final_relative_width for the final phase;
211 doubled for each preceding phase.
212 For example with two intermediate phases,
213 the first intermediate phase uses quadruple of final_relative_width
214 and the second intermediate phase uses double of final_relative_width.
215 c. *in*: ndr_interval, pdr_interval from the previous main loop iteration
216 or the previous phase.
217 If the previous phase is the initial phase, both intervals have
218 lower_bound = MRR2, uper_bound = MRR.
219 Note that the initial phase is likely to create intervals with invalid bounds.
220 d. *do*: According to the procedure described in point 2,
221 either exit the phase (by jumping to 1.g.),
222 or prepare new transmit rate to measure with.
223 e. *do*: Perform the trial measurement at the new transmit rate
224 and trial_duration, compute its loss ratio.
225 f. *do*: Update the bounds of both intervals, based on the new measurement.
226 The actual update rules are numerous, as NDR external search
227 can affect PDR interval and vice versa, but the result
228 agrees with rules of both internal and external search.
229 For example, any new measurement below an invalid lower_bound
230 becomes the new lower_bound, while the old measurement
231 (previously acting as the invalid lower_bound)
232 becomes a new and valid upper_bound.
233 Go to next iteration (1.c.), taking the updated intervals as new input.
234 g. *out*: current ndr_interval and pdr_interval.
235 In the final phase this is also considered
236 to be the result of the whole search.
237 For other phases, the next phase loop is started
238 with the current results as an input.
240 2. New transmit rate (or exit) calculation (for 1.d.):
242 - If there is an invalid bound then prepare for external search:
244 - *If* the most recent measurement at NDR lower_bound transmit rate
245 had the loss higher than zero, then
246 the new transmit rate is NDR lower_bound
247 decreased by two NDR interval widths.
248 - Else, *if* the most recent measurement at PDR lower_bound
249 transmit rate had the loss higher than PLR, then
250 the new transmit rate is PDR lower_bound
251 decreased by two PDR interval widths.
252 - Else, *if* the most recent measurement at NDR upper_bound
253 transmit rate had no loss, then
254 the new transmit rate is NDR upper_bound
255 increased by two NDR interval widths.
256 - Else, *if* the most recent measurement at PDR upper_bound
257 transmit rate had the loss lower or equal to PLR, then
258 the new transmit rate is PDR upper_bound
259 increased by two PDR interval widths.
260 - If interval width is higher than the current phase goal:
262 - Else, *if* NDR interval does not meet the current phase width goal,
263 prepare for internal search. The new transmit rate is
264 (NDR lower bound + NDR upper bound) / 2.
265 - Else, *if* PDR interval does not meet the current phase width goal,
266 prepare for internal search. The new transmit rate is
267 (PDR lower bound + PDR upper bound) / 2.
268 - Else, *if* some bound has still only been measured at a lower duration,
269 prepare to re-measure at the current duration (and the same transmit rate).
270 The order of priorities is:
276 - *Else*, do not prepare any new rate, to exit the phase.
277 This ensures that at the end of each non-initial phase
278 all intervals are valid, narrow enough, and measured
279 at current phase trial duration.
281 Implementation Deviations
282 ~~~~~~~~~~~~~~~~~~~~~~~~~
284 This document so far has been describing a simplified version of MLRsearch algorithm.
285 The full algorithm as implemented contains additional logic,
286 which makes some of the details (but not general ideas) above incorrect.
287 Here is a short description of the additional logic as a list of principles,
288 explaining their main differences from (or additions to) the simplified description,
289 but without detailing their mutual interaction.
291 1. *Logarithmic transmit rate.*
292 In order to better fit the relative width goal,
293 the interval doubling and halving is done differently.
294 For example, the middle of 2 and 8 is 4, not 5.
295 2. *Optimistic maximum rate.*
296 The increased rate is never higher than the maximum rate.
297 Upper bound at that rate is always considered valid.
298 3. *Pessimistic minimum rate.*
299 The decreased rate is never lower than the minimum rate.
300 If a lower bound at that rate is invalid,
301 a phase stops refining the interval further (until it gets re-measured).
302 4. *Conservative interval updates.*
303 Measurements above current upper bound never update a valid upper bound,
304 even if drop ratio is low.
305 Measurements below current lower bound always update any lower bound
306 if drop ratio is high.
307 5. *Ensure sufficient interval width.*
308 Narrow intervals make external search take more time to find a valid bound.
309 If the new transmit increased or decreased rate would result in width
310 less than the current goal, increase/decrease more.
311 This can happen if the measurement for the other interval
312 makes the current interval too narrow.
313 Similarly, take care the measurements in the initial phase
314 create wide enough interval.
315 6. *Timeout for bad cases.*
316 The worst case for MLRsearch is when each phase converges to intervals
317 way different than the results of the previous phase.
318 Rather than suffer total search time several times larger
319 than pure binary search, the implemented tests fail themselves
320 when the search takes too long (given by argument *timeout*).
322 Maximum Receive Rate MRR
323 ------------------------
325 MRR tests measure the packet forwarding rate under the maximum
326 load offered by traffic generator over a set trial duration,
327 regardless of packet loss. Maximum load for specified Ethernet frame
328 size is set to the bi-directional link rate.
330 Current parameters for MRR tests:
332 - Ethernet frame sizes: 64B (78B for IPv6), IMIX, 1518B, 9000B; all
333 quoted sizes include frame CRC, but exclude per frame transmission
334 overhead of 20B (preamble, inter frame gap).
336 - Maximum load offered: 10GE and 40GE link (sub-)rates depending on NIC
337 tested, with the actual packet rate depending on frame size,
338 transmission overhead and traffic generator NIC forwarding capacity.
340 - For 10GE NICs the maximum packet rate load is 2* 14.88 Mpps for 64B,
341 a 10GE bi-directional link rate.
342 - For 25GE NICs the maximum packet rate load is 2* 18.75 Mpps for 64B,
343 a 25GE bi-directional link sub-rate limited by TG 25GE NIC used,
345 - For 40GE NICs the maximum packet rate load is 2* 18.75 Mpps for 64B,
346 a 40GE bi-directional link sub-rate limited by TG 40GE NIC used,
347 XL710. Packet rate for other tested frame sizes is limited by PCIe
348 Gen3 x8 bandwidth limitation of ~50Gbps.
350 - Trial duration: 10sec.
352 Similarly to NDR/PDR throughput tests, MRR test should be reporting bi-
353 directional link rate (or NIC rate, if lower) if tested VPP
354 configuration can handle the packet rate higher than bi-directional link
355 rate, e.g. large packet tests and/or multi-core tests.
357 MRR tests are used for continuous performance trending and for
358 comparison between releases. Daily trending job tests subset of frame
359 sizes, focusing on 64B (78B for IPv6) for all tests and IMIX for
360 selected tests (vhost, memif).
365 TRex Traffic Generator (TG) is used for measuring latency of VPP DUTs.
366 Reported latency values are measured using following methodology:
368 - Latency tests are performed at 100% of discovered NDR and PDR rates
369 for each throughput test and packet size (except IMIX).
370 - TG sends dedicated latency streams, one per direction, each at the
371 rate of 9 kpps at the prescribed packet size; these are sent in
372 addition to the main load streams.
373 - TG reports min/avg/max latency values per stream direction, hence two
374 sets of latency values are reported per test case; future release of
375 TRex is expected to report latency percentiles.
376 - Reported latency values are aggregate across two SUTs due to three
377 node topology used for all performance tests; for per SUT latency,
378 reported value should be divided by two.
379 - 1usec is the measurement accuracy advertised by TRex TG for the setup
380 used in FD.io labs used by CSIT project.
381 - TRex setup introduces an always-on error of about 2*2usec per latency
382 flow additonal Tx/Rx interface latency induced by TRex SW writing and
383 reading packet timestamps on CPU cores without HW acceleration on NICs
384 closer to the interface line.
389 All performance tests are executed with single processor core and with
390 multiple cores scenarios.
392 Intel Hyper-Threading (HT)
393 ~~~~~~~~~~~~~~~~~~~~~~~~~~
395 Intel Xeon processors used in FD.io CSIT can operate either in HT
396 Disabled mode (single logical core per each physical core) or in HT
397 Enabled mode (two logical cores per each physical core). HT setting is
398 applied in BIOS and requires server SUT reload for it to take effect,
399 making it impractical for continuous changes of HT mode of operation.
401 |csit-release| performance tests are executed with server SUTs' Intel
402 XEON processors configured with Intel Hyper-Threading Disabled for all
403 Xeon Haswell testbeds (3n-hsw) and with Intel Hyper-Threading Enabled
404 for all Xeon Skylake testbeds.
406 More information about physical testbeds is provided in
407 :ref:`tested_physical_topologies`.
412 |csit-release| multi-core tests are executed in the following VPP worker
413 thread and physical core configurations:
415 #. Intel Xeon Haswell testbeds (3n-hsw) with Intel HT disabled
416 (1 logical CPU core per each physical core):
418 #. 1t1c - 1 VPP worker thread on 1 physical core.
419 #. 2t2c - 2 VPP worker threads on 2 physical cores.
420 #. 4t4c - 4 VPP worker threads on 4 physical cores.
422 #. Intel Xeon Skylake testbeds (2n-skx, 3n-skx) with Intel HT enabled
423 (2 logical CPU cores per each physical core):
425 #. 2t1c - 2 VPP worker threads on 1 physical core.
426 #. 4t2c - 4 VPP worker threads on 2 physical cores.
427 #. 8t4c - 8 VPP worker threads on 4 physical cores.
429 VPP worker threads are the data plane threads running on isolated
430 logical cores. With Intel HT enabled VPP workers are placed as sibling
431 threads on each used physical core. VPP control threads (main, stats)
432 are running on a separate non-isolated core together with other Linux
435 In all CSIT tests care is taken to ensure that each VPP worker handles
436 the same amount of received packet load and does the same amount of
437 packet processing work. This is achieved by evenly distributing per
438 interface type (e.g. physical, virtual) receive queues over VPP workers
439 using default VPP round- robin mapping and by loading these queues with
440 the same amount of packet flows.
442 If number of VPP workers is higher than number of physical or virtual
443 interfaces, multiple receive queues are configured on each interface.
444 NIC Receive Side Scaling (RSS) for physical interfaces and multi-queue
445 for virtual interfaces are used for this purpose.
447 Section :ref:`throughput_speedup_multi_core` includes a set of graphs
448 illustrating packet throughout speedup when running VPP worker threads
449 on multiple cores. Note that in quite a few test cases running VPP
450 workers on 2 or 4 physical cores hits the I/O bandwidth or packets-per-
451 second limit of tested NIC.
456 CSIT code manipulates a number of VPP settings in startup.conf for optimized
457 performance. List of common settings applied to all tests and test
458 dependent settings follows.
460 See `VPP startup.conf <https://git.fd.io/vpp/tree/src/vpp/conf/startup.conf?h=stable/1807>`_
461 for a complete set and description of listed settings.
466 List of vpp startup.conf settings applied to all tests:
468 #. heap-size <value> - set separately for ip4, ip6, stats, main
469 depending on scale tested.
470 #. no-tx-checksum-offload - disables UDP / TCP TX checksum offload in DPDK.
471 Typically needed for use faster vector PMDs (together with
473 #. socket-mem <value>,<value> - memory per numa. (Not required anymore
474 due to VPP code changes, should be removed in CSIT-18.10.)
479 List of vpp startup.conf settings applied dynamically per test:
481 #. corelist-workers <list_of_cores> - list of logical cores to run VPP
482 worker data plane threads. Depends on HyperThreading and core per
484 #. num-rx-queues <value> - depends on a number of VPP threads and NIC
486 #. num-rx-desc/num-tx-desc - number of rx/tx descriptors for specific
487 NICs, incl. xl710, x710, xxv710.
488 #. num-mbufs <value> - increases number of buffers allocated, needed
489 only in scenarios with large number of interfaces and worker threads.
490 Value is per CPU socket. Default is 16384.
491 #. no-multi-seg - disables multi-segment buffers in DPDK, improves
492 packet throughput, but disables Jumbo MTU support. Disabled for all
493 tests apart from the ones that require Jumbo 9000B frame support.
494 #. UIO driver - depends on topology file definition.
495 #. QAT VFs - depends on NRThreads, each thread = 1QAT VFs.
500 FD.io CSIT performance lab is testing VPP vhost with KVM VMs using
501 following environment settings:
503 - Tests with varying Qemu virtio queue (a.k.a. vring) sizes: [vr256]
504 default 256 descriptors, [vr1024] 1024 descriptors to optimize for
506 - Tests with varying Linux :abbr:`CFS (Completely Fair Scheduler)`
507 settings: [cfs] default settings, [cfsrr1] CFS RoundRobin(1) policy
508 applied to all data plane threads handling test packet path including
509 all VPP worker threads and all Qemu testpmd poll-mode threads.
510 - Resulting test cases are all combinations with [vr256,vr1024] and
511 [cfs,cfsrr1] settings.
512 - Adjusted Linux kernel :abbr:`CFS (Completely Fair Scheduler)`
513 scheduler policy for data plane threads used in CSIT is documented in
514 `CSIT Performance Environment Tuning wiki <https://wiki.fd.io/view/CSIT/csit-perf-env-tuning-ubuntu1604>`_.
515 - The purpose is to verify performance impact (MRR and NDR/PDR
516 throughput) and same test measurements repeatability, by making VPP
517 and VM data plane threads less susceptible to other Linux OS system
518 tasks hijacking CPU cores running those data plane threads.
520 LXC/DRC Container Memif
521 -----------------------
523 |csit-release| includes tests taking advantage of VPP memif virtual
524 interface (shared memory interface) to interconnect VPP running in
525 Containers. VPP vswitch instance runs in bare-metal user-mode handling
526 NIC interfaces and connecting over memif (Slave side) to VPPs running in
527 :abbr:`Linux Container (LXC)` or in Docker Container (DRC) configured
528 with memif (Master side). LXCs and DRCs run in a priviliged mode with
529 VPP data plane worker threads pinned to dedicated physical CPU cores per
530 usual CSIT practice. All VPP instances run the same version of software.
531 This test topology is equivalent to existing tests with vhost-user and
532 VMs as described earlier in :ref:`tested_logical_topologies`.
534 In addition to above vswitch tests, a single memif interface test is
535 executed. It runs in a simple topology of two VPP container instances
536 connected over memif interface in order to verify standalone memif
537 interface performance.
539 More information about CSIT LXC and DRC setup and control is available
540 in :ref:`container_orchestration_in_csit`.
545 |csit-release| includes tests of VPP topologies running in K8s
546 orchestrated Pods/Containers and connected over memif virtual
547 interfaces. In order to provide simple topology coding flexibility and
548 extensibility container orchestration is done with `Kubernetes
549 <https://github.com/kubernetes>`_ using `Docker
550 <https://github.com/docker>`_ images for all container applications
551 including VPP. `Ligato <https://github.com/ligato>`_ is used for the
552 Pod/Container networking orchestration that is integrated with K8s,
553 including memif support.
555 In these tests VPP vswitch runs in a K8s Pod with Docker Container (DRC)
556 handling NIC interfaces and connecting over memif to more instances of
557 VPP running in Pods/DRCs. All DRCs run in a priviliged mode with VPP
558 data plane worker threads pinned to dedicated physical CPU cores per
559 usual CSIT practice. All VPP instances run the same version of software.
560 This test topology is equivalent to existing tests with vhost-user and
561 VMs as described earlier in :ref:`tested_physical_topologies`.
563 Further documentation is available in
564 :ref:`container_orchestration_in_csit`.
569 VPP IPSec performance tests are using DPDK cryptodev device driver in
570 combination with HW cryptodev devices - Intel QAT 8950 50G - present in
571 LF FD.io physical testbeds. DPDK cryptodev can be used for all IPSec
572 data plane functions supported by VPP.
574 Currently |csit-release| implements following IPSec test cases:
576 - AES-GCM, CBC-SHA1 ciphers, in combination with IPv4 routed-forwarding
577 with Intel xl710 NIC.
578 - CBC-SHA1 ciphers, in combination with LISP-GPE overlay tunneling for
579 IPv4-over-IPv4 with Intel xl710 NIC.
581 TRex Traffic Generator
582 ----------------------
587 `TRex traffic generator <https://wiki.fd.io/view/TRex>`_ is used for all
588 CSIT performance tests. TRex stateless mode is used to measure NDR and
589 PDR throughputs using binary search (NDR and PDR discovery tests) and
590 for quick checks of DUT performance against the reference NDRs (NDR
591 check tests) for specific configuration.
593 TRex is installed and run on the TG compute node. The typical procedure
596 - If the TRex is not already installed on TG, it is installed in the
597 suite setup phase - see `TRex intallation`_.
598 - TRex configuration is set in its configuration file
603 - TRex is started in the background mode
606 $ sh -c 'cd <t-rex-install-dir>/scripts/ && sudo nohup ./t-rex-64 -i -c 7 --iom 0 > /tmp/trex.log 2>&1 &' > /dev/null
608 - There are traffic streams dynamically prepared for each test, based on traffic
609 profiles. The traffic is sent and the statistics obtained using
610 :command:`trex_stl_lib.api.STLClient`.
612 Measuring Packet Loss
613 ~~~~~~~~~~~~~~~~~~~~~
615 Following sequence is followed to measure packet loss:
617 - Create an instance of STLClient.
618 - Connect to the client.
621 - Send the traffic for defined time.
622 - Get the statistics.
624 If there is a warm-up phase required, the traffic is sent also before
625 test and the statistics are ignored.
630 If measurement of latency is requested, two more packet streams are
631 created (one for each direction) with TRex flow_stats parameter set to
632 STLFlowLatencyStats. In that case, returned statistics will also include
633 min/avg/max latency values.
635 HTTP/TCP with WRK tool
636 ----------------------
638 `WRK HTTP benchmarking tool <https://github.com/wg/wrk>`_ is used for
639 experimental TCP/IP and HTTP tests of VPP TCP/IP stack and built-in
640 static HTTP server. WRK has been chosen as it is capable of generating
641 significant TCP/IP and HTTP loads by scaling number of threads across
642 multi-core processors.
644 This in turn enables quite high scale benchmarking of the main TCP/IP
645 and HTTP service including HTTP TCP/IP Connections-Per-Second (CPS),
646 HTTP Requests-Per-Second and HTTP Bandwidth Throughput.
648 The initial tests are designed as follows:
650 - HTTP and TCP/IP Connections-Per-Second (CPS)
652 - WRK configured to use 8 threads across 8 cores, 1 thread per core.
653 - Maximum of 50 concurrent connections across all WRK threads.
654 - Timeout for server responses set to 5 seconds.
655 - Test duration is 30 seconds.
656 - Expected HTTP test sequence:
658 - Single HTTP GET Request sent per open connection.
659 - Connection close after valid HTTP reply.
660 - Resulting flow sequence - 8 packets: >Syn, <Syn-Ack, >Ack, >Req,
661 <Rep, >Fin, <Fin, >Ack.
663 - HTTP Requests-Per-Second
665 - WRK configured to use 8 threads across 8 cores, 1 thread per core.
666 - Maximum of 50 concurrent connections across all WRK threads.
667 - Timeout for server responses set to 5 seconds.
668 - Test duration is 30 seconds.
669 - Expected HTTP test sequence:
671 - Multiple HTTP GET Requests sent in sequence per open connection.
672 - Connection close after set test duration time.
673 - Resulting flow sequence: >Syn, <Syn-Ack, >Ack, >Req[1], <Rep[1],
674 .., >Req[n], <Rep[n], >Fin, <Fin, >Ack.
676 .. _binary search: https://en.wikipedia.org/wiki/Binary_search
677 .. _exponential search: https://en.wikipedia.org/wiki/Exponential_search
678 .. _estimation of standard deviation: https://en.wikipedia.org/wiki/Unbiased_estimation_of_standard_deviation
679 .. _simplified error propagation formula: https://en.wikipedia.org/wiki/Propagation_of_uncertainty#Simplification