When testing ring performance in the case that multiple lcores are mapped
to the same physical core, e.g. --lcores '(0-3)@10', it takes a very long
time to wait for the "enqueue_dequeue_bulk_helper" to finish.
This is because too much iteration numbers and extremely low efficiency
for enqueue and dequeue with this kind of core mapping. Following are the
test results to show the above phenomenon:
x86-Intel(R) Xeon(R) Gold 6240:
$sudo ./app/test/dpdk-test --lcores '(0-1)@25'
Testing using two hyperthreads(bulk (size: 8):)
iter_shift: 3 5 7 9 11 13 *15 17 19 21 23
run time: 7s 7s 7s 8s 9s 16s 47s 170s 660s >0.5h >1h
legacy APIs: SP/SC: 37 11 6 40525 40525 40209 40367 40407 40541 NoData NoData
legacy APIs: MP/MC: 56 14 11 50657 40526 40526 40526 40625 40585 NoData NoData
aarch64-n1sdp:
$sudo ./app/test/dpdk-test --lcore '(0-1)@1'
Testing using two hyperthreads(bulk (size: 8):)
iter_shift: 3 5 7 9 11 13 *15 17 19 21 23
run time: 8s 8s 8s 9s 9s 14s 34s 111s 418s 25min >1h
legacy APIs: SP/SC: 0.4 0.2 0.1 488 488 488 488 488 489 489 NoData
legacy APIs: MP/MC: 0.4 0.3 0.2 488 488 488 488 490 489 489 NoData
As the number of iterations increases, so does the time which is required
to run the program. Currently (iter_shift = 23), it will take more than
1 hour to wait for the test to finish. To fix this, the "iter_shift" should
decrease and ensure enough iterations to keep the test data stable.
In order to achieve this, we also test with "-l" EAL argument:
x86-Intel(R) Xeon(R) Gold 6240:
$sudo ./app/test/dpdk-test -l 25-26
Testing using two NUMA nodes(bulk (size: 8):)
iter_shift: 3 5 7 9 11 13 *15 17 19 21 23
run time: 6s 6s 6s 6s 6s 6s 6s 7s 8s 11s 27s
legacy APIs: SP/SC: 47 20 13 22 54 83 91 73 81 75 95
legacy APIs: MP/MC: 44 18 18 240 245 270 250 249 252 250 253
aarch64-n1sdp:
$sudo ./app/test/dpdk-test -l 1-2
Testing using two physical cores(bulk (size: 8):)
iter_shift: 3 5 7 9 11 13 *15 17 19 21 23
run time: 8s 8s 8s 8s 8s 8s 8s 9s 9s 11s 23s
legacy APIs: SP/SC: 0.7 0.4 1.2 1.8 2.0 2.0 2.0 2.0 2.0 2.0 2.0
legacy APIs: MP/MC: 0.3 0.4 1.3 1.9 2.9 2.9 2.9 2.9 2.9 2.9 2.9
According to above test data, when "iter_shift" is set as "15", the test
run time is reduced to less than 1 minute and the test result can keep
stable in x86 and aarch64 servers.
Fixes: 1fa5d0099e ("test/ring: add custom element size performance tests")
Cc: stable@dpdk.org
Signed-off-by: Feifei Wang <feifei.wang2@arm.com>
Reviewed-by: Honnappa Nagarahalli <honnappa.nagarahalli@arm.com>
Reviewed-by: Ruifeng Wang <ruifeng.wang@arm.com>
Acked-by: Konstantin Ananyev <konstantin.ananyev@intel.com>
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