Messages in this thread Patch in this message | | | From | Song Liu <> | Subject | Re: [PATCH v5 5/5] perf-stat: introduce bpf_counter_ops->disable() | Date | Thu, 29 Apr 2021 22:40:01 +0000 |
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> On Apr 27, 2021, at 12:30 PM, Song Liu <songliubraving@fb.com> wrote: > > > >> On Apr 27, 2021, at 5:33 AM, Jiri Olsa <jolsa@redhat.com> wrote: >> >> On Mon, Apr 26, 2021 at 10:18:57PM +0000, Song Liu wrote: >>> >>> >>>> On Apr 26, 2021, at 2:27 PM, Jiri Olsa <jolsa@redhat.com> wrote: >>>> >>>> On Sun, Apr 25, 2021 at 02:43:33PM -0700, Song Liu wrote: >>>> >>>> SNIP >>>> >>>>> +static inline int bpf_counter__disable(struct evsel *evsel __maybe_unused) >>>>> +{ >>>>> + return 0; >>>>> +} >>>>> + >>>>> static inline int bpf_counter__read(struct evsel *evsel __maybe_unused) >>>>> { >>>>> return -EAGAIN; >>>>> diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c >>>>> index d29a8a118973c..e71041c890102 100644 >>>>> --- a/tools/perf/util/evlist.c >>>>> +++ b/tools/perf/util/evlist.c >>>>> @@ -17,6 +17,7 @@ >>>>> #include "evsel.h" >>>>> #include "debug.h" >>>>> #include "units.h" >>>>> +#include "bpf_counter.h" >>>>> #include <internal/lib.h> // page_size >>>>> #include "affinity.h" >>>>> #include "../perf.h" >>>>> @@ -421,6 +422,9 @@ static void __evlist__disable(struct evlist *evlist, char *evsel_name) >>>>> if (affinity__setup(&affinity) < 0) >>>>> return; >>>>> >>>>> + evlist__for_each_entry(evlist, pos) >>>>> + bpf_counter__disable(pos); >>>> >>>> I was wondering why you don't check evsel__is_bpf like >>>> for the enable case.. and realized that we don't skip >>>> bpf evsels in __evlist__enable and __evlist__disable >>>> like we do in read_affinity_counters >>>> >>>> so I guess there's extra affinity setup and bunch of >>>> wrong ioctls being called? >>> >>> We actually didn't do wrong ioctls because the following check: >>> >>> if (... || !pos->core.fd) >>> continue; >>> >>> in __evlist__enable and __evlist__disable. That we don't allocate >>> core.fd for is_bpf events. >>> >>> It is probably good to be more safe with an extra check of >>> evsel__is_bpf(). But it is not required with current code. >> >> hum, but it will do all the affinity setup no? for no reason, >> if there's no non-bpb event > > Yes, it will do the affinity setup. Let me see how to get something > like all_counters_use_bpf here (or within builtin-stat.c). >
Would something like the following work? It is not clean (skipping some useful logic in __evlist__[enable|disable]). But it seems to work in the tests.
Thanks, Song
From ecb75a1fa747ca5521bcda972840df1e97c09b11 Mon Sep 17 00:00:00 2001 From: Song Liu <song@kernel.org> Date: Wed, 28 Apr 2021 17:41:28 -0700 Subject: [PATCH] perf-stat: skip evlist__[enable|disable] when all events uses BPF
When all events of a perf-stat session use BPF, it is not necessary to call evlist__enable() and evlist__disable(). Skip them when all_counters_use_bpf is true.
Signed-off-by: Song Liu <song@kernel.org> --- tools/perf/builtin-stat.c | 12 +++++++++--- tools/perf/util/evlist.c | 3 --- 2 files changed, 9 insertions(+), 6 deletions(-)
diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c index 5a830ae09418e..44459e0352fda 100644 --- a/tools/perf/builtin-stat.c +++ b/tools/perf/builtin-stat.c @@ -572,7 +572,8 @@ static int enable_counters(void) * - we have initial delay configured */ if (!target__none(&target) || stat_config.initial_delay) { - evlist__enable(evsel_list); + if (!all_counters_use_bpf) + evlist__enable(evsel_list); if (stat_config.initial_delay > 0) pr_info(EVLIST_ENABLED_MSG); } @@ -581,13 +582,18 @@ static int enable_counters(void)
static void disable_counters(void) { + struct evsel *counter; /* * If we don't have tracee (attaching to task or cpu), counters may * still be running. To get accurate group ratios, we must stop groups * from counting before reading their constituent counters. */ - if (!target__none(&target)) - evlist__disable(evsel_list); + if (!target__none(&target)) { + evlist__for_each_entry(evsel_list, counter) + bpf_counter__disable(counter); + if (!all_counters_use_bpf) + evlist__disable(evsel_list); + } }
static volatile int workload_exec_errno; diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c index 6e5c41528c7d0..6ea3e677dc1e7 100644 --- a/tools/perf/util/evlist.c +++ b/tools/perf/util/evlist.c @@ -425,9 +425,6 @@ static void __evlist__disable(struct evlist *evlist, char *evsel_name) if (affinity__setup(&affinity) < 0) return;
- evlist__for_each_entry(evlist, pos) - bpf_counter__disable(pos); - /* Disable 'immediate' events last */ for (imm = 0; imm <= 1; imm++) { evlist__for_each_cpu(evlist, i, cpu) { -- 2.30.2
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