Messages in this thread | | | Date | Thu, 22 Apr 2021 14:02:13 +0800 | From | Oliver Sang <> | Subject | Re: [signal] 4bad58ebc8: will-it-scale.per_thread_ops -3.3% regression |
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hi, Thomas Gleixner,
On Tue, Apr 20, 2021 at 08:35:06PM +0200, Thomas Gleixner wrote: > On Tue, Apr 20 2021 at 11:08, kernel test robot wrote: > > FYI, we noticed a -3.3% regression of will-it-scale.per_thread_ops due to commit: > > > > commit: 4bad58ebc8bc4f20d89cff95417c9b4674769709 ("signal: Allow tasks to cache one sigqueue struct") > > https://git.kernel.org/cgit/linux/kernel/git/tip/tip.git sched/core > > > > in testcase: will-it-scale > > on test machine: 192 threads Intel(R) Xeon(R) Platinum 9242 CPU @ 2.30GHz with 192G memory > > with following parameters: > > > > nr_task: 100% > > mode: thread > > test: futex3 > > cpufreq_governor: performance > > ucode: 0x5003006 > > > > test-description: Will It Scale takes a testcase and runs it from 1 through to n parallel copies to see if the testcase will scale. It builds both a process and threads based test in order to see any differences between the two. > > test-url: https://github.com/antonblanchard/will-it-scale > > commit: > > 69995ebbb9 ("signal: Hand SIGQUEUE_PREALLOC flag to __sigqueue_alloc()") > > 4bad58ebc8 ("signal: Allow tasks to cache one sigqueue struct") > > > > 69995ebbb9d37173 4bad58ebc8bc4f20d89cff95417 > > ---------------- --------------------------- > > %stddev %change %stddev > > \ | \ > > 1.273e+09 -3.3% 1.231e+09 will-it-scale.192.threads > > 6630224 -3.3% 6409738 will-it-scale.per_thread_ops > > 1.273e+09 -3.3% 1.231e+09 will-it-scale.workload > > 1638 ± 3% -7.8% 1510 ± 5% sched_debug.cfs_rq:/.runnable_avg.max > > 297.83 ± 68% +1747.6% 5502 ±152% interrupts.33:PCI-MSI.524291-edge.eth0-TxRx-2 > > 297.83 ± 68% +1747.6% 5502 ±152% interrupts.CPU12.33:PCI-MSI.524291-edge.eth0-TxRx-2 > > This change is definitely not causing more network traffic > > > 8200 -33.4% 5459 ± 35% interrupts.CPU27.NMI:Non-maskable_interrupts > > 8200 -33.4% 5459 ± 35% interrupts.CPU27.PMI:Performance_monitoring_interrupts > > 8199 -33.4% 5459 ± 35% interrupts.CPU28.NMI:Non-maskable_interrupts > > 8199 -33.4% 5459 ± 35% interrupts.CPU28.PMI:Performance_monitoring_interrupts > > 6148 ± 33% -11.2% 5459 ± 35% interrupts.CPU29.NMI:Non-maskable_interrupts > > 6148 ± 33% -11.2% 5459 ± 35% interrupts.CPU29.PMI:Performance_monitoring_interrupts > > 4287 ± 8% +33.6% 5730 ± 15% interrupts.CPU49.CAL:Function_call_interrupts > > 6356 ± 19% +49.6% 9509 ± 19% interrupts.CPU97.CAL:Function_call_interrupts > > Neither does it increase the number of function calls > > > 407730 ± 8% +37.5% 560565 ± 7% perf-stat.i.dTLB-load-misses > > 415959 ± 8% +40.4% 583928 ± 7% perf-stat.ps.dTLB-load-misses > > And this massive increase does not make sense either. > > Confused.
FYI. we re-test this, and confirmed the regression persistent. still:
69995ebbb9d37173 4bad58ebc8bc4f20d89cff95417 ---------------- --------------------------- %stddev %change %stddev \ | \ 1.271e+09 -3.3% 1.229e+09 will-it-scale.192.threads 6620228 -3.3% 6401749 will-it-scale.per_thread_ops 1.271e+09 -3.3% 1.229e+09 will-it-scale.workload
both fbc and parent use identical config, as attached in original report.
data for 4bad58ebc8bc4f20d89cff95417: 4bad58ebc8bc4f20d89cff95417c9b4674769709/matrix.json: "will-it-scale.per_thread_ops": [ 4bad58ebc8bc4f20d89cff95417c9b4674769709/matrix.json- 6404491, 4bad58ebc8bc4f20d89cff95417c9b4674769709/matrix.json- 6421116, 4bad58ebc8bc4f20d89cff95417c9b4674769709/matrix.json- 6402763, 4bad58ebc8bc4f20d89cff95417c9b4674769709/matrix.json- 6403483, 4bad58ebc8bc4f20d89cff95417c9b4674769709/matrix.json- 6412066, 4bad58ebc8bc4f20d89cff95417c9b4674769709/matrix.json- 6414511, 4bad58ebc8bc4f20d89cff95417c9b4674769709/matrix.json- 6395917, <------ new 14 runs 4bad58ebc8bc4f20d89cff95417c9b4674769709/matrix.json- 6396872, 4bad58ebc8bc4f20d89cff95417c9b4674769709/matrix.json- 6400830, 4bad58ebc8bc4f20d89cff95417c9b4674769709/matrix.json- 6408883, 4bad58ebc8bc4f20d89cff95417c9b4674769709/matrix.json- 6403844, 4bad58ebc8bc4f20d89cff95417c9b4674769709/matrix.json- 6405911, 4bad58ebc8bc4f20d89cff95417c9b4674769709/matrix.json- 6390766, 4bad58ebc8bc4f20d89cff95417c9b4674769709/matrix.json- 6394523, 4bad58ebc8bc4f20d89cff95417c9b4674769709/matrix.json- 6394594, 4bad58ebc8bc4f20d89cff95417c9b4674769709/matrix.json- 6399547, 4bad58ebc8bc4f20d89cff95417c9b4674769709/matrix.json- 6402487, 4bad58ebc8bc4f20d89cff95417c9b4674769709/matrix.json- 6394673, 4bad58ebc8bc4f20d89cff95417c9b4674769709/matrix.json- 6400717, 4bad58ebc8bc4f20d89cff95417c9b4674769709/matrix.json- 6386997
data for parent (69995ebbb9d37173): 69995ebbb9d3717306a165db88a1292b63f77a37/matrix.json: "will-it-scale.per_thread_ops": [ 69995ebbb9d3717306a165db88a1292b63f77a37/matrix.json- 6640509, 69995ebbb9d3717306a165db88a1292b63f77a37/matrix.json- 6630326, 69995ebbb9d3717306a165db88a1292b63f77a37/matrix.json- 6633025, 69995ebbb9d3717306a165db88a1292b63f77a37/matrix.json- 6625355, 69995ebbb9d3717306a165db88a1292b63f77a37/matrix.json- 6623274, 69995ebbb9d3717306a165db88a1292b63f77a37/matrix.json- 6628858, 69995ebbb9d3717306a165db88a1292b63f77a37/matrix.json- 6614380, <----- new 14 runs 69995ebbb9d3717306a165db88a1292b63f77a37/matrix.json- 6607324, 69995ebbb9d3717306a165db88a1292b63f77a37/matrix.json- 6613340, 69995ebbb9d3717306a165db88a1292b63f77a37/matrix.json- 6610083, 69995ebbb9d3717306a165db88a1292b63f77a37/matrix.json- 6616290, 69995ebbb9d3717306a165db88a1292b63f77a37/matrix.json- 6616934, 69995ebbb9d3717306a165db88a1292b63f77a37/matrix.json- 6618978, 69995ebbb9d3717306a165db88a1292b63f77a37/matrix.json- 6627108, 69995ebbb9d3717306a165db88a1292b63f77a37/matrix.json- 6609973, 69995ebbb9d3717306a165db88a1292b63f77a37/matrix.json- 6618440, 69995ebbb9d3717306a165db88a1292b63f77a37/matrix.json- 6617191, 69995ebbb9d3717306a165db88a1292b63f77a37/matrix.json- 6615858, 69995ebbb9d3717306a165db88a1292b63f77a37/matrix.json- 6615761, 69995ebbb9d3717306a165db88a1292b63f77a37/matrix.json- 6621558
> > Thanks, > > tglx
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