From: "Liang, Kan" <kan.liang@linux.intel.com> To: Ian Rogers <irogers@google.com>, Carel Si <beibei.si@intel.com> Cc: acme@redhat.com, alexander.shishkin@linux.intel.com, alexandre.torgue@foss.st.com, ak@linux.intel.com, mingo@redhat.com, james.clark@arm.com, jolsa@kernel.org, john.garry@huawei.com, mark.rutland@arm.com, mcoquelin.stm32@gmail.com, namhyung@kernel.org, peterz@infradead.org, eranian@google.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org, lkp@lists.01.org, lkp@intel.com Subject: Re: [LKP] Re: [perf vendor events] 3f5f0df7bf: perf-sanity-tests.perf_all_metrics_test.fail Date: Wed, 13 Apr 2022 12:37:24 -0400 [thread overview] Message-ID: <85eed89f-e4a8-2887-a0b3-579704304357@linux.intel.com> (raw) In-Reply-To: <CAP-5=fXGqODZYGu781qjEEVtGFpCQJ=dCXi5shYOAbBSt5wQkw@mail.gmail.com> On 4/13/2022 12:03 PM, Ian Rogers wrote: > 3) Weak group doesn't fall back to no group: That's because the group validation code doesn't take pinned events, such as the NMI watchdog, into account. I proposed a kernel patch to fix it, but it's rejected. It should be hard to find a generic way to fix it from the kernel side. https://lore.kernel.org/lkml/1565977750-76693-1-git-send-email-kan.liang@linux.intel.com/ Maybe we can workaround it from the perf tool side? For example, for each weak group with cycles event and NMI watchdog is enabled, add an extra cycles event when opening the group. If the open fails with the extra cycles event, fall back to no group. After the extra cycles event check, remove the extra cycles. What do you think? Thanks, Kan > $ perf stat -e '{BR_INST_RETIRED.NEAR_CALL,BR_INST_RETIRED.NEAR_TAKEN,BR_INST_RETIRED.NOT_TAKEN,BR_INST_RETIRED.CONDITIONAL,CPU_CLK_UNHALTED.THREAD}:W' > -a sleep 1 > > Performance counter stats for 'system wide': > > <not counted> BR_INST_RETIRED.NEAR_CALL > (0.00%) > <not counted> BR_INST_RETIRED.NEAR_TAKEN > (0.00%) > <not counted> BR_INST_RETIRED.NOT_TAKEN > (0.00%) > <not counted> BR_INST_RETIRED.CONDITIONAL > (0.00%) > <not counted> CPU_CLK_UNHALTED.THREAD > (0.00%) > > 1.001690318 seconds time elapsed > > Some events weren't counted. Try disabling the NMI watchdog: > echo 0 > /proc/sys/kernel/nmi_watchdog > perf stat ... > echo 1 > /proc/sys/kernel/nmi_watchdog
WARNING: multiple messages have this Message-ID (diff)
From: Liang, Kan <kan.liang@linux.intel.com> To: lkp@lists.01.org Subject: Re: [perf vendor events] 3f5f0df7bf: perf-sanity-tests.perf_all_metrics_test.fail Date: Wed, 13 Apr 2022 12:37:24 -0400 [thread overview] Message-ID: <85eed89f-e4a8-2887-a0b3-579704304357@linux.intel.com> (raw) In-Reply-To: <CAP-5=fXGqODZYGu781qjEEVtGFpCQJ=dCXi5shYOAbBSt5wQkw@mail.gmail.com> [-- Attachment #1: Type: text/plain, Size: 1646 bytes --] On 4/13/2022 12:03 PM, Ian Rogers wrote: > 3) Weak group doesn't fall back to no group: That's because the group validation code doesn't take pinned events, such as the NMI watchdog, into account. I proposed a kernel patch to fix it, but it's rejected. It should be hard to find a generic way to fix it from the kernel side. https://lore.kernel.org/lkml/1565977750-76693-1-git-send-email-kan.liang(a)linux.intel.com/ Maybe we can workaround it from the perf tool side? For example, for each weak group with cycles event and NMI watchdog is enabled, add an extra cycles event when opening the group. If the open fails with the extra cycles event, fall back to no group. After the extra cycles event check, remove the extra cycles. What do you think? Thanks, Kan > $ perf stat -e '{BR_INST_RETIRED.NEAR_CALL,BR_INST_RETIRED.NEAR_TAKEN,BR_INST_RETIRED.NOT_TAKEN,BR_INST_RETIRED.CONDITIONAL,CPU_CLK_UNHALTED.THREAD}:W' > -a sleep 1 > > Performance counter stats for 'system wide': > > <not counted> BR_INST_RETIRED.NEAR_CALL > (0.00%) > <not counted> BR_INST_RETIRED.NEAR_TAKEN > (0.00%) > <not counted> BR_INST_RETIRED.NOT_TAKEN > (0.00%) > <not counted> BR_INST_RETIRED.CONDITIONAL > (0.00%) > <not counted> CPU_CLK_UNHALTED.THREAD > (0.00%) > > 1.001690318 seconds time elapsed > > Some events weren't counted. Try disabling the NMI watchdog: > echo 0 > /proc/sys/kernel/nmi_watchdog > perf stat ... > echo 1 > /proc/sys/kernel/nmi_watchdog
next prev parent reply other threads:[~2022-04-13 16:37 UTC|newest] Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top 2022-03-04 8:33 [perf vendor events] 3f5f0df7bf: perf-sanity-tests.perf_all_metrics_test.fail kernel test robot 2022-03-04 8:33 ` kernel test robot 2022-03-04 18:10 ` Ian Rogers 2022-03-04 18:10 ` Ian Rogers 2022-04-13 7:05 ` [LKP] " Carel Si 2022-04-13 7:05 ` Carel Si 2022-04-13 16:03 ` [LKP] " Ian Rogers 2022-04-13 16:03 ` Ian Rogers 2022-04-13 16:37 ` Liang, Kan [this message] 2022-04-13 16:37 ` Liang, Kan 2022-04-13 17:09 ` [LKP] " Ian Rogers 2022-04-13 17:09 ` Ian Rogers 2022-04-13 18:17 ` [LKP] " Liang, Kan 2022-04-13 18:17 ` Liang, Kan 2022-04-14 16:09 ` [LKP] " Ian Rogers 2022-04-14 16:09 ` Ian Rogers 2022-04-14 19:06 ` [LKP] " Liang, Kan 2022-04-14 19:06 ` Liang, Kan 2022-04-14 22:58 ` [LKP] " Namhyung Kim 2022-04-14 22:58 ` Namhyung Kim 2022-04-18 12:42 ` [LKP] " Liang, Kan 2022-04-18 12:42 ` Liang, Kan
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