* [BUG] perf: cannot read counts in per-process mode in 3.17-rcX
@ 2014-09-08 12:35 Stephane Eranian
2014-09-08 12:49 ` Jiri Olsa
0 siblings, 1 reply; 8+ messages in thread
From: Stephane Eranian @ 2014-09-08 12:35 UTC (permalink / raw)
To: LKML
Cc: Peter Zijlstra, Jiri Olsa, mingo, Arnaldo Carvalho de Melo,
Namhyung Kim, ak, David Ahern
Hi,
It seems something is seriously broken with perf_events in
3.17-rcX. I have tried rc3, rc4. No way to get any counts
out using perf stat in per-process mode. I am trying on Intel
and the PMU is correctly detected:
$ perf stat -e cycles ls
<not counted> cycles
It is not a permission problem. It is a read problem!
$ strace perf stat -e cycles ls
perf_event_open(0x27d7e20, 2261, -1, -1, 0x8 /* PERF_FLAG_??? */) = 3
write(6, "\0", 1) = 1
close(6) = 0
wait4(-1, [{WIFEXITED(s) && WEXITSTATUS(s) == 0}], 0, NULL) = 2261
--- SIGCHLD {si_signo=SIGCHLD, si_code=CLD_EXITED, si_pid=2261,
si_status=0, si_utime=0, si_stime=0} ---
rt_sigreturn() = 2261
read(3, "", 24) = 0
^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Looks like read() on the perf returns 0 (nothing read!).
It seems to work fine in system-wide mode. So I bet there were some
recent changes in the way the events are stored when the process
terminates.
I think the perf tool is not to blame here. I see the same problem with my
libpfm4 toy examples.
Can you reproduce the problem on your system?
^ permalink raw reply [flat|nested] 8+ messages in thread* Re: [BUG] perf: cannot read counts in per-process mode in 3.17-rcX 2014-09-08 12:35 [BUG] perf: cannot read counts in per-process mode in 3.17-rcX Stephane Eranian @ 2014-09-08 12:49 ` Jiri Olsa 2014-09-08 13:21 ` Stephane Eranian 0 siblings, 1 reply; 8+ messages in thread From: Jiri Olsa @ 2014-09-08 12:49 UTC (permalink / raw) To: Stephane Eranian Cc: LKML, Peter Zijlstra, mingo, Arnaldo Carvalho de Melo, Namhyung Kim, ak, David Ahern On Mon, Sep 08, 2014 at 02:35:06PM +0200, Stephane Eranian wrote: > Hi, > > It seems something is seriously broken with perf_events in > 3.17-rcX. I have tried rc3, rc4. No way to get any counts > out using perf stat in per-process mode. I am trying on Intel > and the PMU is correctly detected: > > $ perf stat -e cycles ls > <not counted> cycles > > It is not a permission problem. It is a read problem! > $ strace perf stat -e cycles ls > > perf_event_open(0x27d7e20, 2261, -1, -1, 0x8 /* PERF_FLAG_??? */) = 3 > write(6, "\0", 1) = 1 > close(6) = 0 > wait4(-1, [{WIFEXITED(s) && WEXITSTATUS(s) == 0}], 0, NULL) = 2261 > --- SIGCHLD {si_signo=SIGCHLD, si_code=CLD_EXITED, si_pid=2261, > si_status=0, si_utime=0, si_stime=0} --- > rt_sigreturn() = 2261 > read(3, "", 24) = 0 > ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ ouch thats me.. sry :-\ the PERF_EVENT_STATE_EXIT check should not go to the read path.. could you please test attached patch? jirka --- diff --git a/kernel/events/core.c b/kernel/events/core.c index d8cb4d2..6d1c9ce 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -3600,8 +3600,7 @@ perf_read_hw(struct perf_event *event, char __user *buf, size_t count) * error state (i.e. because it was pinned but it couldn't be * scheduled on to the CPU at some point). */ - if ((event->state == PERF_EVENT_STATE_ERROR) || - (event->state == PERF_EVENT_STATE_EXIT)) + if (event->state == PERF_EVENT_STATE_ERROR) return 0; if (count < event->read_size) ^ permalink raw reply related [flat|nested] 8+ messages in thread
* Re: [BUG] perf: cannot read counts in per-process mode in 3.17-rcX 2014-09-08 12:49 ` Jiri Olsa @ 2014-09-08 13:21 ` Stephane Eranian 2014-09-08 14:31 ` [PATCH] perf: Do not check PERF_EVENT_STATE_EXIT on syscall read path Jiri Olsa 0 siblings, 1 reply; 8+ messages in thread From: Stephane Eranian @ 2014-09-08 13:21 UTC (permalink / raw) To: Jiri Olsa Cc: LKML, Peter Zijlstra, mingo, Arnaldo Carvalho de Melo, Namhyung Kim, ak, David Ahern On Mon, Sep 8, 2014 at 2:49 PM, Jiri Olsa <jolsa@redhat.com> wrote: > > On Mon, Sep 08, 2014 at 02:35:06PM +0200, Stephane Eranian wrote: > > Hi, > > > > It seems something is seriously broken with perf_events in > > 3.17-rcX. I have tried rc3, rc4. No way to get any counts > > out using perf stat in per-process mode. I am trying on Intel > > and the PMU is correctly detected: > > > > $ perf stat -e cycles ls > > <not counted> cycles > > > > It is not a permission problem. It is a read problem! > > $ strace perf stat -e cycles ls > > > > perf_event_open(0x27d7e20, 2261, -1, -1, 0x8 /* PERF_FLAG_??? */) = 3 > > write(6, "\0", 1) = 1 > > close(6) = 0 > > wait4(-1, [{WIFEXITED(s) && WEXITSTATUS(s) == 0}], 0, NULL) = 2261 > > --- SIGCHLD {si_signo=SIGCHLD, si_code=CLD_EXITED, si_pid=2261, > > si_status=0, si_utime=0, si_stime=0} --- > > rt_sigreturn() = 2261 > > read(3, "", 24) = 0 > > ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ > > ouch thats me.. sry :-\ > > the PERF_EVENT_STATE_EXIT check should not go to the > read path.. could you please test attached patch? > > jirka > Works for me again now. Thanks for the quick fix. Please push it upstream. Acked-by: Stephane Eranian <eranian@google.com> > > > --- > diff --git a/kernel/events/core.c b/kernel/events/core.c > index d8cb4d2..6d1c9ce 100644 > --- a/kernel/events/core.c > +++ b/kernel/events/core.c > @@ -3600,8 +3600,7 @@ perf_read_hw(struct perf_event *event, char __user *buf, size_t count) > * error state (i.e. because it was pinned but it couldn't be > * scheduled on to the CPU at some point). > */ > - if ((event->state == PERF_EVENT_STATE_ERROR) || > - (event->state == PERF_EVENT_STATE_EXIT)) > + if (event->state == PERF_EVENT_STATE_ERROR) > return 0; > > if (count < event->read_size) ^ permalink raw reply [flat|nested] 8+ messages in thread
* [PATCH] perf: Do not check PERF_EVENT_STATE_EXIT on syscall read path 2014-09-08 13:21 ` Stephane Eranian @ 2014-09-08 14:31 ` Jiri Olsa 2014-09-08 15:22 ` Peter Zijlstra 2014-09-16 10:58 ` [tip:perf/core] " tip-bot for Jiri Olsa 0 siblings, 2 replies; 8+ messages in thread From: Jiri Olsa @ 2014-09-08 14:31 UTC (permalink / raw) To: Stephane Eranian Cc: LKML, Peter Zijlstra, mingo, Arnaldo Carvalho de Melo, Namhyung Kim, ak, David Ahern On Mon, Sep 08, 2014 at 03:21:12PM +0200, Stephane Eranian wrote: > On Mon, Sep 8, 2014 at 2:49 PM, Jiri Olsa <jolsa@redhat.com> wrote: > > > > On Mon, Sep 08, 2014 at 02:35:06PM +0200, Stephane Eranian wrote: > > > Hi, > > > > > > It seems something is seriously broken with perf_events in > > > 3.17-rcX. I have tried rc3, rc4. No way to get any counts > > > out using perf stat in per-process mode. I am trying on Intel > > > and the PMU is correctly detected: > > > > > > $ perf stat -e cycles ls > > > <not counted> cycles > > > > > > It is not a permission problem. It is a read problem! > > > $ strace perf stat -e cycles ls > > > > > > perf_event_open(0x27d7e20, 2261, -1, -1, 0x8 /* PERF_FLAG_??? */) = 3 > > > write(6, "\0", 1) = 1 > > > close(6) = 0 > > > wait4(-1, [{WIFEXITED(s) && WEXITSTATUS(s) == 0}], 0, NULL) = 2261 > > > --- SIGCHLD {si_signo=SIGCHLD, si_code=CLD_EXITED, si_pid=2261, > > > si_status=0, si_utime=0, si_stime=0} --- > > > rt_sigreturn() = 2261 > > > read(3, "", 24) = 0 > > > ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ > > > > ouch thats me.. sry :-\ > > > > the PERF_EVENT_STATE_EXIT check should not go to the > > read path.. could you please test attached patch? > > > > jirka > > > Works for me again now. Thanks for the quick fix. Please push it upstream. > > Acked-by: Stephane Eranian <eranian@google.com> attached, thanks jirka --- Revert PERF_EVENT_STATE_EXIT check on read syscall path. It breaks standard way to read counter, which is to open the counter, wait for the monitored process to die and read the counter. Reported-by: Stephane Eranian <eranian@google.com> Acked-by: Stephane Eranian <eranian@google.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Stephane Eranian <eranian@google.com> Signed-off-by: Jiri Olsa <jolsa@kernel.org> --- kernel/events/core.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/kernel/events/core.c b/kernel/events/core.c index d8cb4d21a346..6d1c9ce1643e 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -3600,8 +3600,7 @@ perf_read_hw(struct perf_event *event, char __user *buf, size_t count) * error state (i.e. because it was pinned but it couldn't be * scheduled on to the CPU at some point). */ - if ((event->state == PERF_EVENT_STATE_ERROR) || - (event->state == PERF_EVENT_STATE_EXIT)) + if (event->state == PERF_EVENT_STATE_ERROR) return 0; if (count < event->read_size) -- 1.8.3.1 ^ permalink raw reply related [flat|nested] 8+ messages in thread
* Re: [PATCH] perf: Do not check PERF_EVENT_STATE_EXIT on syscall read path 2014-09-08 14:31 ` [PATCH] perf: Do not check PERF_EVENT_STATE_EXIT on syscall read path Jiri Olsa @ 2014-09-08 15:22 ` Peter Zijlstra 2014-09-10 13:49 ` Stephane Eranian 2014-09-16 10:58 ` [tip:perf/core] " tip-bot for Jiri Olsa 1 sibling, 1 reply; 8+ messages in thread From: Peter Zijlstra @ 2014-09-08 15:22 UTC (permalink / raw) To: Jiri Olsa Cc: Stephane Eranian, LKML, mingo, Arnaldo Carvalho de Melo, Namhyung Kim, ak, David Ahern [-- Attachment #1: Type: text/plain, Size: 1406 bytes --] On Mon, Sep 08, 2014 at 04:31:07PM +0200, Jiri Olsa wrote: > Revert PERF_EVENT_STATE_EXIT check on read syscall path. > It breaks standard way to read counter, which is to open > the counter, wait for the monitored process to die and > read the counter. > > Reported-by: Stephane Eranian <eranian@google.com> > Acked-by: Stephane Eranian <eranian@google.com> > Cc: Arnaldo Carvalho de Melo <acme@redhat.com> > Cc: Frederic Weisbecker <fweisbec@gmail.com> > Cc: Ingo Molnar <mingo@kernel.org> > Cc: Paul Mackerras <paulus@samba.org> > Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> > Cc: Stephane Eranian <eranian@google.com> > Signed-off-by: Jiri Olsa <jolsa@kernel.org> Thanks! > --- > kernel/events/core.c | 3 +-- > 1 file changed, 1 insertion(+), 2 deletions(-) > > diff --git a/kernel/events/core.c b/kernel/events/core.c > index d8cb4d21a346..6d1c9ce1643e 100644 > --- a/kernel/events/core.c > +++ b/kernel/events/core.c > @@ -3600,8 +3600,7 @@ perf_read_hw(struct perf_event *event, char __user *buf, size_t count) > * error state (i.e. because it was pinned but it couldn't be > * scheduled on to the CPU at some point). > */ > - if ((event->state == PERF_EVENT_STATE_ERROR) || > - (event->state == PERF_EVENT_STATE_EXIT)) > + if (event->state == PERF_EVENT_STATE_ERROR) > return 0; > > if (count < event->read_size) > -- > 1.8.3.1 > [-- Attachment #2: Type: application/pgp-signature, Size: 836 bytes --] ^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH] perf: Do not check PERF_EVENT_STATE_EXIT on syscall read path 2014-09-08 15:22 ` Peter Zijlstra @ 2014-09-10 13:49 ` Stephane Eranian 2014-09-15 10:29 ` Stephane Eranian 0 siblings, 1 reply; 8+ messages in thread From: Stephane Eranian @ 2014-09-10 13:49 UTC (permalink / raw) To: Peter Zijlstra Cc: Jiri Olsa, LKML, mingo, Arnaldo Carvalho de Melo, Namhyung Kim, ak, David Ahern Peter, On Mon, Sep 8, 2014 at 5:22 PM, Peter Zijlstra <peterz@infradead.org> wrote: > On Mon, Sep 08, 2014 at 04:31:07PM +0200, Jiri Olsa wrote: >> Revert PERF_EVENT_STATE_EXIT check on read syscall path. >> It breaks standard way to read counter, which is to open >> the counter, wait for the monitored process to die and >> read the counter. >> >> Reported-by: Stephane Eranian <eranian@google.com> >> Acked-by: Stephane Eranian <eranian@google.com> >> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> >> Cc: Frederic Weisbecker <fweisbec@gmail.com> >> Cc: Ingo Molnar <mingo@kernel.org> >> Cc: Paul Mackerras <paulus@samba.org> >> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> >> Cc: Stephane Eranian <eranian@google.com> >> Signed-off-by: Jiri Olsa <jolsa@kernel.org> > > Thanks! Still don't see this fix in tip.git. >> --- >> kernel/events/core.c | 3 +-- >> 1 file changed, 1 insertion(+), 2 deletions(-) >> >> diff --git a/kernel/events/core.c b/kernel/events/core.c >> index d8cb4d21a346..6d1c9ce1643e 100644 >> --- a/kernel/events/core.c >> +++ b/kernel/events/core.c >> @@ -3600,8 +3600,7 @@ perf_read_hw(struct perf_event *event, char __user *buf, size_t count) >> * error state (i.e. because it was pinned but it couldn't be >> * scheduled on to the CPU at some point). >> */ >> - if ((event->state == PERF_EVENT_STATE_ERROR) || >> - (event->state == PERF_EVENT_STATE_EXIT)) >> + if (event->state == PERF_EVENT_STATE_ERROR) >> return 0; >> >> if (count < event->read_size) >> -- >> 1.8.3.1 >> ^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH] perf: Do not check PERF_EVENT_STATE_EXIT on syscall read path 2014-09-10 13:49 ` Stephane Eranian @ 2014-09-15 10:29 ` Stephane Eranian 0 siblings, 0 replies; 8+ messages in thread From: Stephane Eranian @ 2014-09-15 10:29 UTC (permalink / raw) To: Peter Zijlstra Cc: Jiri Olsa, LKML, mingo, Arnaldo Carvalho de Melo, Namhyung Kim, ak, David Ahern On Wed, Sep 10, 2014 at 3:49 PM, Stephane Eranian <eranian@google.com> wrote: > > Peter, > > > > On Mon, Sep 8, 2014 at 5:22 PM, Peter Zijlstra <peterz@infradead.org> wrote: > > On Mon, Sep 08, 2014 at 04:31:07PM +0200, Jiri Olsa wrote: > >> Revert PERF_EVENT_STATE_EXIT check on read syscall path. > >> It breaks standard way to read counter, which is to open > >> the counter, wait for the monitored process to die and > >> read the counter. > >> > >> Reported-by: Stephane Eranian <eranian@google.com> > >> Acked-by: Stephane Eranian <eranian@google.com> > >> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> > >> Cc: Frederic Weisbecker <fweisbec@gmail.com> > >> Cc: Ingo Molnar <mingo@kernel.org> > >> Cc: Paul Mackerras <paulus@samba.org> > >> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> > >> Cc: Stephane Eranian <eranian@google.com> > >> Signed-off-by: Jiri Olsa <jolsa@kernel.org> > > > > Thanks! > Still don't see this fix in tip.git. > Still not there. This is a problem. > > >> --- > >> kernel/events/core.c | 3 +-- > >> 1 file changed, 1 insertion(+), 2 deletions(-) > >> > >> diff --git a/kernel/events/core.c b/kernel/events/core.c > >> index d8cb4d21a346..6d1c9ce1643e 100644 > >> --- a/kernel/events/core.c > >> +++ b/kernel/events/core.c > >> @@ -3600,8 +3600,7 @@ perf_read_hw(struct perf_event *event, char __user *buf, size_t count) > >> * error state (i.e. because it was pinned but it couldn't be > >> * scheduled on to the CPU at some point). > >> */ > >> - if ((event->state == PERF_EVENT_STATE_ERROR) || > >> - (event->state == PERF_EVENT_STATE_EXIT)) > >> + if (event->state == PERF_EVENT_STATE_ERROR) > >> return 0; > >> > >> if (count < event->read_size) > >> -- > >> 1.8.3.1 > >> ^ permalink raw reply [flat|nested] 8+ messages in thread
* [tip:perf/core] perf: Do not check PERF_EVENT_STATE_EXIT on syscall read path 2014-09-08 14:31 ` [PATCH] perf: Do not check PERF_EVENT_STATE_EXIT on syscall read path Jiri Olsa 2014-09-08 15:22 ` Peter Zijlstra @ 2014-09-16 10:58 ` tip-bot for Jiri Olsa 1 sibling, 0 replies; 8+ messages in thread From: tip-bot for Jiri Olsa @ 2014-09-16 10:58 UTC (permalink / raw) To: linux-tip-commits Cc: linux-kernel, paulus, acme, eranian, hpa, mingo, jolsa, a.p.zijlstra, namhyung, jolsa, fweisbec, dsahern, tglx Commit-ID: c88f2096136416b261bd3647cc260935f6e95805 Gitweb: http://git.kernel.org/tip/c88f2096136416b261bd3647cc260935f6e95805 Author: Jiri Olsa <jolsa@redhat.com> AuthorDate: Mon, 8 Sep 2014 16:31:07 +0200 Committer: Ingo Molnar <mingo@kernel.org> CommitDate: Tue, 16 Sep 2014 10:30:36 +0200 perf: Do not check PERF_EVENT_STATE_EXIT on syscall read path Revert PERF_EVENT_STATE_EXIT check on read syscall path. It breaks standard way to read counter, which is to open the counter, wait for the monitored process to die and read the counter. Reported-by: Stephane Eranian <eranian@google.com> Signed-off-by: Jiri Olsa <jolsa@kernel.org> Acked-by: Stephane Eranian <eranian@google.com> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Stephane Eranian <eranian@google.com> Cc: David Ahern <dsahern@gmail.com> Link: http://lkml.kernel.org/r/20140908143107.GG17728@krava.brq.redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org> --- kernel/events/core.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/kernel/events/core.c b/kernel/events/core.c index f917dec..733c616 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -3601,8 +3601,7 @@ perf_read_hw(struct perf_event *event, char __user *buf, size_t count) * error state (i.e. because it was pinned but it couldn't be * scheduled on to the CPU at some point). */ - if ((event->state == PERF_EVENT_STATE_ERROR) || - (event->state == PERF_EVENT_STATE_EXIT)) + if (event->state == PERF_EVENT_STATE_ERROR) return 0; if (count < event->read_size) ^ permalink raw reply related [flat|nested] 8+ messages in thread
end of thread, other threads:[~2014-09-16 10:58 UTC | newest] Thread overview: 8+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2014-09-08 12:35 [BUG] perf: cannot read counts in per-process mode in 3.17-rcX Stephane Eranian 2014-09-08 12:49 ` Jiri Olsa 2014-09-08 13:21 ` Stephane Eranian 2014-09-08 14:31 ` [PATCH] perf: Do not check PERF_EVENT_STATE_EXIT on syscall read path Jiri Olsa 2014-09-08 15:22 ` Peter Zijlstra 2014-09-10 13:49 ` Stephane Eranian 2014-09-15 10:29 ` Stephane Eranian 2014-09-16 10:58 ` [tip:perf/core] " tip-bot for Jiri Olsa
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