Messages in this thread | | | Date | Wed, 20 Nov 2019 18:10:02 +0000 | From | Qais Yousef <> | Subject | Re: [PATCH v4 11/11] sched/fair: rework find_idlest_group |
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On 11/20/19 18:43, Vincent Guittot wrote: > On Wed, 20 Nov 2019 at 18:34, Qais Yousef <qais.yousef@arm.com> wrote: > > > > On 11/20/19 17:53, Vincent Guittot wrote: > > > On Wed, 20 Nov 2019 at 14:21, Vincent Guittot > > > <vincent.guittot@linaro.org> wrote: > > > > > > > > Hi Qais, > > > > > > > > On Wed, 20 Nov 2019 at 12:58, Qais Yousef <qais.yousef@arm.com> wrote: > > > > > > > > > > Hi Vincent > > > > > > > > > > On 10/18/19 15:26, Vincent Guittot wrote: > > > > > > The slow wake up path computes per sched_group statisics to select the > > > > > > idlest group, which is quite similar to what load_balance() is doing > > > > > > for selecting busiest group. Rework find_idlest_group() to classify the > > > > > > sched_group and select the idlest one following the same steps as > > > > > > load_balance(). > > > > > > > > > > > > Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org> > > > > > > --- > > > > > > > > > > LTP test has caught a regression in perf_event_open02 test on linux-next and I > > > > > bisected it to this patch. > > > > > > > > > > That is checking out next-20191119 tag and reverting this patch on top the test > > > > > passes. Without the revert the test fails. > > > > > > I haven't tried linux-next yet but LTP test is passed with > > > tip/sched/core, which includes this patch, on hikey960 which is arm64 > > > too. > > > > > > Have you tried tip/sched/core on your juno ? this could help to > > > understand if it's only for juno or if this patch interact with > > > another branch merged in linux next > > > > Okay will give it a go. But out of curiosity, what is the output of your run? > > > > While bisecting on linux-next I noticed that at some point the test was > > passing but all the read values were 0. At some point I started seeing > > none-zero values. > > for tip/sched/core > linaro@linaro-developer:~/ltp/testcases/kernel/syscalls/perf_event_open$ > sudo ./perf_event_open02 > perf_event_open02 0 TINFO : overall task clock: 63724479 > perf_event_open02 0 TINFO : hw sum: 1800900992, task clock sum: 382170311 > perf_event_open02 0 TINFO : ratio: 5.997229 > perf_event_open02 1 TPASS : test passed > > for next-2019119 > ~/ltp/testcases/kernel/syscalls/perf_event_open$ sudo ./perf_event_open02 -v > at iteration:0 value:0 time_enabled:69795312 time_running:0 > perf_event_open02 0 TINFO : overall task clock: 63582292 > perf_event_open02 0 TINFO : hw sum: 0, task clock sum: 0 > hw counters: 0 0 0 0 > task clock counters: 0 0 0 0 > perf_event_open02 0 TINFO : ratio: 0.000000 > perf_event_open02 1 TPASS : test passed
Okay that is weird. But ratio, hw sum, task clock sum are all 0 in your next-20191119. I'm not sure why the counters return 0 sometimes - is it dependent on some option or a bug somewhere.
I just did another run and it failed for me (building with defconfig)
# uname -a Linux buildroot 5.4.0-rc8-next-20191119 #72 SMP PREEMPT Wed Nov 20 17:57:48 GMT 2019 aarch64 GNU/Linux
# ./perf_event_open02 -v at iteration:0 value:260700250 time_enabled:172739760 time_running:144956600 perf_event_open02 0 TINFO : overall task clock: 166915220 perf_event_open02 0 TINFO : hw sum: 1200718268, task clock sum: 667621320 hw counters: 300179051 300179395 300179739 300180083 task clock counters: 166906620 166906200 166905160 166903340 perf_event_open02 0 TINFO : ratio: 3.999763 perf_event_open02 0 TINFO : nhw: 0.000100 perf_event_open02 1 TFAIL : perf_event_open02.c:370: test failed (ratio was greater than )
It is a funny one for sure. I haven't tried tip/sched/core yet.
Thanks
-- Qais Yousef
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