From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jan Stancek Date: Wed, 13 Dec 2017 15:42:13 -0500 (EST) Subject: [LTP] [PATCH V3] ltp: Add a zero latency constraint for the timer tests library In-Reply-To: References: <20170817135029.GA31322@rei> <1502982026-4113-1-git-send-email-daniel.lezcano@linaro.org> <20170818122533.GD22319@rei.lan> <1864131650.54048676.1513090088938.JavaMail.zimbra@redhat.com> <1566390724.54053292.1513091073892.JavaMail.zimbra@redhat.com> <0dd9434e-01b0-e7dd-9984-f787a1a08d99@linaro.org> Message-ID: <196315459.54339372.1513197733270.JavaMail.zimbra@redhat.com> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 8bit To: ltp@lists.linux.it ----- Original Message ----- > On 12/12/2017 16:21, Daniel Lezcano wrote: > > > > On Intel, the firmware usually overrides the kernel power management > > decision by auto-promoting the idle states. Yeah, I was saving BIOS as last option. > > > > So it is possible it is the case for you. With a process keeping the CPU > > "busy" that prevents the firmware to go to a deepest idle state. > > > > I see it is a Xeon platform. You can try by checking the > > performance/power balance option in the BIOS. AFAIR, there is > > performance aggressive, power aggressive, balanced-performance+ and > > balanced-power+ and balanced. > > > > Can you check this option ? > > So ? any news from the front ? Not yet, it's a remote system and I can't get into BIOS atm. > > > On 12/12/2017 16:04, Jan Stancek wrote: > >> > >> > >> ----- Original Message ----- > >>> On 12/12/2017 15:48, Jan Stancek wrote: > >>>> Hi, > >>>> > >>>> I'm running into similar problem on "Dell Precision 5820 tower", with > >>>> Intel(R) Xeon(R) W-2133 CPU @ 3.60GHz, but I can't find any /proc /sys > >>>> knob that would help. > >>>> > >>>> # uname -r > >>>> 4.14.5 > >>>> > >>>> # cat /sys/devices/system/cpu/cpu*/cpufreq/scaling_governor > >>>> performance > >>>> performance > >>>> performance > >>>> performance > >>>> performance > >>>> performance > >>>> performance > >>>> performance > >>>> performance > >>>> performance > >>>> performance > >>>> performance > >>>> > >>>> Any timer related tests are reliably failing on longer timeouts: > >>>> --- > >>>> tst_test.c:934: INFO: Timeout per run is 0h 05m 00s > >>>> tst_timer_test.c:356: INFO: CLOCK_MONOTONIC resolution 1ns > >>>> tst_timer_test.c:368: INFO: prctl(PR_GET_TIMERSLACK) = 50us > >>>> tst_timer_test.c:275: INFO: poll() sleeping for 1000us 500 iterations, > >>>> threshold 450.01us > >>>> tst_timer_test.c:318: INFO: min 1095us, max 1098us, median 1096us, trunc > >>>> mean 1095.99us (discarded 25) > >>>> tst_timer_test.c:333: PASS: Measured times are within thresholds > >>>> tst_timer_test.c:275: INFO: poll() sleeping for 2000us 500 iterations, > >>>> threshold 450.01us > >>>> tst_timer_test.c:318: INFO: min 2062us, max 2138us, median 2137us, trunc > >>>> mean 2135.98us (discarded 25) > >>>> tst_timer_test.c:333: PASS: Measured times are within thresholds > >>>> tst_timer_test.c:275: INFO: poll() sleeping for 5000us 300 iterations, > >>>> threshold 450.04us > >>>> tst_timer_test.c:318: INFO: min 5262us, max 5263us, median 5262us, trunc > >>>> mean 5262.20us (discarded 15) > >>>> tst_timer_test.c:333: PASS: Measured times are within thresholds > >>>> tst_timer_test.c:275: INFO: poll() sleeping for 10000us 100 iterations, > >>>> threshold 450.33us > >>>> tst_timer_test.c:318: INFO: min 10318us, max 10471us, median 10471us, > >>>> trunc > >>>> mean 10469.07us (discarded 5) > >>>> tst_timer_test.c:321: FAIL: poll() slept for too long > >>> > >>> Are you running the tests with this zero latency patch included ? > >> > >> Yes, I'm running ltp release 20170929, which has your patch. > >> > >> ... > >> [pid 18276] 09:59:21.379883 open("/dev/cpu_dma_latency", O_WRONLY) = 3 > >> [pid 18276] 09:59:21.379906 write(3, "\0\0\0\0", 4) = 4 > >> ... > >> > >> I tried it without that patch, and it started failing more with smaller > >> timeouts. > >> > >> Regards, > >> Jan > >> > >>> > >>> > >>>> SCHED_OTHER or SCHED_FIFO -> FAIL > >>>> intel_idle.max_cstate=0 processor.max_cstate=1 -> FAIL > >>>> echo 1 > /sys/devices/system/cpu/intel_pstate/no_turbo -> FAIL > >>>> idle=halt -> FAIL > >>>> idle=poll -> FAIL > >>>> > >>>> Only thing I found to help is to keep CPU slightly busy with > >>>> taskset -c 1 sh -c "while [ True ]; do usleep 100; done" > >>>> > >>>> After that it started to PASS: > >>>> > >>>> # taskset -c 1 ./poll02 > >>>> tst_test.c:934: INFO: Timeout per run is 0h 05m 00s > >>>> tst_timer_test.c:356: INFO: CLOCK_MONOTONIC resolution 1ns > >>>> tst_timer_test.c:368: INFO: prctl(PR_GET_TIMERSLACK) = 50us > >>>> tst_timer_test.c:275: INFO: poll() sleeping for 1000us 500 iterations, > >>>> threshold 450.01us > >>>> tst_timer_test.c:318: INFO: min 1004us, max 1325us, median 1072us, trunc > >>>> mean 1149.29us (discarded 25) > >>>> tst_timer_test.c:333: PASS: Measured times are within thresholds > >>>> tst_timer_test.c:275: INFO: poll() sleeping for 2000us 500 iterations, > >>>> threshold 450.01us > >>>> tst_timer_test.c:318: INFO: min 2007us, max 2326us, median 2075us, trunc > >>>> mean 2158.64us (discarded 25) > >>>> tst_timer_test.c:333: PASS: Measured times are within thresholds > >>>> tst_timer_test.c:275: INFO: poll() sleeping for 5000us 300 iterations, > >>>> threshold 450.04us > >>>> tst_timer_test.c:318: INFO: min 5006us, max 5345us, median 5074us, trunc > >>>> mean 5146.84us (discarded 15) > >>>> tst_timer_test.c:333: PASS: Measured times are within thresholds > >>>> tst_timer_test.c:275: INFO: poll() sleeping for 10000us 100 iterations, > >>>> threshold 450.33us > >>>> tst_timer_test.c:318: INFO: min 10004us, max 10364us, median 10075us, > >>>> trunc > >>>> mean 10128.61us (discarded 5) > >>>> tst_timer_test.c:333: PASS: Measured times are within thresholds > >>>> tst_timer_test.c:275: INFO: poll() sleeping for 25000us 50 iterations, > >>>> threshold 451.29us > >>>> tst_timer_test.c:318: INFO: min 25006us, max 25359us, median 25072us, > >>>> trunc > >>>> mean 25137.48us (discarded 2) > >>>> tst_timer_test.c:333: PASS: Measured times are within thresholds > >>>> tst_timer_test.c:275: INFO: poll() sleeping for 100000us 10 iterations, > >>>> threshold 537.00us > >>>> tst_timer_test.c:318: INFO: min 100010us, max 100372us, median 100125us, > >>>> trunc mean 100167.78us (discarded 1) > >>>> tst_timer_test.c:333: PASS: Measured times are within thresholds > >>>> tst_timer_test.c:275: INFO: poll() sleeping for 1000000us 2 iterations, > >>>> threshold 4400.00us > >>>> tst_timer_test.c:318: INFO: min 1000843us, max 1000920us, median > >>>> 1000843us, > >>>> trunc mean 1000843.00us (discarded 1) > >>>> tst_timer_test.c:333: PASS: Measured times are within thresholds > >>>> > >>>> Summary: > >>>> passed 7 > >>>> failed 0 > >>>> skipped 0 > >>>> warnings 0 > >>>> > >>>> Any ideas? > >>>> > >>>> Regards, > >>>> Jan > >>>> > >>> > >>> > >>> -- > >>> Linaro.org │ Open source software for ARM SoCs > >>> > >>> Follow Linaro: Facebook | > >>> Twitter | > >>> Blog > >>> > >>> > >>> -- > >>> Mailing list info: https://lists.linux.it/listinfo/ltp > >>> > > > > > > > -- > Linaro.org │ Open source software for ARM SoCs > > Follow Linaro: Facebook | > Twitter | > Blog > >