An -ENOMEM error is not reported in the GTK GUI.
Instead this error message pops up on the screen:
[root@m35lp76 perf]# ./perf report -i perf.data.error68-1
Processing events... [974K/3M]
Error:failed to process sample
0xf4198 [0x8]: failed to process type: 68
However when I use the same perf.data file with --stdio it works:
[root@m35lp76 perf]# ./perf report -i perf.data.error68-1 --stdio \
| head -12
# Total Lost Samples: 0
#
# Samples: 76K of event 'cycles'
# Event count (approx.): 99056160000
#
# Overhead Command Shared Object Symbol
# ........ ............... ................. .........
#
8.81% find [kernel.kallsyms] [k] ftrace_likely_update
8.74% swapper [kernel.kallsyms] [k] ftrace_likely_update
8.34% sshd [kernel.kallsyms] [k] ftrace_likely_update
2.19% kworker/u512:1- [kernel.kallsyms] [k] ftrace_likely_update
The sample precentage is a bit low.....
The GUI always fails in the FINISHED_ROUND event (68) and does not
indicate the reason why.
When happened is the following. Perf report calls a lot of functions and
down deep when a FINISHED_ROUND event is processed, these functions are
called:
perf_session__process_event()
+ perf_session__process_user_event()
+ process_finished_round()
+ ordered_events__flush()
+ __ordered_events__flush()
+ do_flush()
+ ordered_events__deliver_event()
+ perf_session__deliver_event()
+ machine__deliver_event()
+ perf_evlist__deliver_event()
+ process_sample_event()
+ hist_entry_iter_add() --> only called in GUI case!!!
+ hist_iter__report__callback()
+ symbol__inc_addr_sample()
Now this functions runs out of memory and
returns -ENOMEM. This is reported all the way up
until function
perf_session__process_event() returns to its caller, where -ENOMEM is
changed to -EINVAL and processing stops:
if ((skip = perf_session__process_event(session, event, head)) < 0) {
pr_err("%#" PRIx64 " [%#x]: failed to process type: %d\n",
head, event->header.size, event->header.type);
err = -EINVAL;
goto out_err;
}
This occurred in the FINISHED_ROUND event when it has to process some
10000 entries and ran out of memory.
This patch indicates the root cause and displays it in the status line
of ther perf report GUI.
Output before (on GUI status line):
0xf4198 [0x8]: failed to process type: 68
Output after:
0xf4198 [0x8]: failed to process type: 68 [not enough memory]
Signed-off-by: Thomas Richter <[email protected]>
Reviewed-by: Jiri Olsa <[email protected]>
Reviewed-by: Hendrik Brueckner <[email protected]>
---
tools/perf/util/session.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/tools/perf/util/session.c b/tools/perf/util/session.c
index b17f1c9bc965..e89716175588 100644
--- a/tools/perf/util/session.c
+++ b/tools/perf/util/session.c
@@ -1930,10 +1930,10 @@ reader__process_events(struct reader *rd, struct perf_session *session,
if (size < sizeof(struct perf_event_header) ||
(skip = rd->process(session, event, file_pos)) < 0) {
- pr_err("%#" PRIx64 " [%#x]: failed to process type: %d\n",
+ pr_err("%#" PRIx64 " [%#x]: failed to process type: %d [%s]\n",
file_offset + head, event->header.size,
- event->header.type);
- err = -EINVAL;
+ event->header.type, strerror(-skip));
+ err = skip;
goto out;
}
--
2.16.4
Em Tue, Apr 23, 2019 at 12:53:03PM +0200, Thomas Richter escreveu:
> An -ENOMEM error is not reported in the GTK GUI.
> Instead this error message pops up on the screen:
>
> [root@m35lp76 perf]# ./perf report -i perf.data.error68-1
>
> Processing events... [974K/3M]
> Error:failed to process sample
>
> 0xf4198 [0x8]: failed to process type: 68
Thanks, applied to perf/urgent.
- Arnaldo
Em Fri, Apr 26, 2019 at 11:10:32AM -0300, Arnaldo Carvalho de Melo escreveu:
> Em Fri, Apr 26, 2019 at 11:09:07AM -0300, Arnaldo Carvalho de Melo escreveu:
> > Em Tue, Apr 23, 2019 at 12:53:03PM +0200, Thomas Richter escreveu:
> > > An -ENOMEM error is not reported in the GTK GUI.
> > > Instead this error message pops up on the screen:
> > >
> > > [root@m35lp76 perf]# ./perf report -i perf.data.error68-1
> > >
> > > Processing events... [974K/3M]
> > > Error:failed to process sample
> > >
> > > 0xf4198 [0x8]: failed to process type: 68
> >
> > Thanks, applied to perf/urgent.
>
> Well, I tried to, now trying to fix this...
>
>
> [acme@quaco perf]$ m
> make: Entering directory '/home/acme/git/perf/tools/perf'
> BUILD: Doing 'make -j8' parallel build
> INSTALL GTK UI
> INSTALL trace_plugins
> CC /tmp/build/perf/util/session.o
> util/session.c: In function ‘perf_session__process_events’:
> util/session.c:1936:7: error: ‘skip’ may be used uninitialized in this function [-Werror=maybe-uninitialized]
> err = skip;
> ~~~~^~~~~~
> util/session.c:1874:6: note: ‘skip’ was declared here
> s64 skip;
> ^~~~
> cc1: all warnings being treated as errors
> mv: cannot stat '/tmp/build/perf/util/.session.o.tmp': No such file or directory
> make[4]: *** [/home/acme/git/perf/tools/build/Makefile.build:96: /tmp/build/perf/util/session.o] Error 1
> make[3]: *** [/home/acme/git/perf/tools/build/Makefile.build:139: util] Error 2
> make[2]: *** [Makefile.perf:559: /tmp/build/perf/perf-in.o] Error 2
> make[1]: *** [Makefile.perf:215: sub-make] Error 2
> make: *** [Makefile:110: install-bin] Error 2
> make: Leaving directory '/home/acme/git/perf/tools/perf'
So, here is your patch:
diff --git a/tools/perf/util/session.c b/tools/perf/util/session.c
index b17f1c9bc965..e89716175588 100644
--- a/tools/perf/util/session.c
+++ b/tools/perf/util/session.c
@@ -1930,10 +1930,10 @@ reader__process_events(struct reader *rd, struct perf_session *session,
if (size < sizeof(struct perf_event_header) ||
(skip = rd->process(session, event, file_pos)) < 0) {
- pr_err("%#" PRIx64 " [%#x]: failed to process type: %d\n",
+ pr_err("%#" PRIx64 " [%#x]: failed to process type: %d [%s]\n",
file_offset + head, event->header.size,
- event->header.type);
- err = -EINVAL;
+ event->header.type, strerror(-skip));
+ err = skip;
goto out;
}
[acme@quaco perf]$
What happens if (size < sizeof(struct perf_event_header)) is true? size
will have an undefined value, so the right thing is to have this patch
on top of yours, so that err get, as before, set to -EINVAL when the
size is less than the perf_event_header sizeof:
diff --git a/tools/perf/util/session.c b/tools/perf/util/session.c
index e89716175588..bad5f87ae001 100644
--- a/tools/perf/util/session.c
+++ b/tools/perf/util/session.c
@@ -1928,6 +1928,8 @@ reader__process_events(struct reader *rd, struct perf_session *session,
size = event->header.size;
+ skip = -EINVAL;
+
if (size < sizeof(struct perf_event_header) ||
(skip = rd->process(session, event, file_pos)) < 0) {
pr_err("%#" PRIx64 " [%#x]: failed to process type: %d [%s]\n",
---
With two Reviewed-by tags, I jumped to quickly at applying, please
compile test next time guys ;-) :-)
- Arnaldo
Em Fri, Apr 26, 2019 at 11:09:07AM -0300, Arnaldo Carvalho de Melo escreveu:
> Em Tue, Apr 23, 2019 at 12:53:03PM +0200, Thomas Richter escreveu:
> > An -ENOMEM error is not reported in the GTK GUI.
> > Instead this error message pops up on the screen:
> >
> > [root@m35lp76 perf]# ./perf report -i perf.data.error68-1
> >
> > Processing events... [974K/3M]
> > Error:failed to process sample
> >
> > 0xf4198 [0x8]: failed to process type: 68
>
> Thanks, applied to perf/urgent.
Well, I tried to, now trying to fix this...
[acme@quaco perf]$ m
make: Entering directory '/home/acme/git/perf/tools/perf'
BUILD: Doing 'make -j8' parallel build
INSTALL GTK UI
INSTALL trace_plugins
CC /tmp/build/perf/util/session.o
util/session.c: In function ‘perf_session__process_events’:
util/session.c:1936:7: error: ‘skip’ may be used uninitialized in this function [-Werror=maybe-uninitialized]
err = skip;
~~~~^~~~~~
util/session.c:1874:6: note: ‘skip’ was declared here
s64 skip;
^~~~
cc1: all warnings being treated as errors
mv: cannot stat '/tmp/build/perf/util/.session.o.tmp': No such file or directory
make[4]: *** [/home/acme/git/perf/tools/build/Makefile.build:96: /tmp/build/perf/util/session.o] Error 1
make[3]: *** [/home/acme/git/perf/tools/build/Makefile.build:139: util] Error 2
make[2]: *** [Makefile.perf:559: /tmp/build/perf/perf-in.o] Error 2
make[1]: *** [Makefile.perf:215: sub-make] Error 2
make: *** [Makefile:110: install-bin] Error 2
make: Leaving directory '/home/acme/git/perf/tools/perf'
Performance counter stats for 'make -k O=/tmp/build/perf -C tools/perf install-bin':
4,913,757,758 cycles:u
7,432,572,002 instructions:u # 1.51 insn per cycle
1.345541349 seconds time elapsed
1.412713000 seconds user
0.572540000 seconds sys
[acme@quaco perf]$
On Fri, Apr 26, 2019 at 11:16:07AM -0300, Arnaldo Carvalho de Melo wrote:
SNIP
> > util/session.c: In function ‘perf_session__process_events’:
> > util/session.c:1936:7: error: ‘skip’ may be used uninitialized in this function [-Werror=maybe-uninitialized]
> > err = skip;
> > ~~~~^~~~~~
> > util/session.c:1874:6: note: ‘skip’ was declared here
> > s64 skip;
> > ^~~~
> > cc1: all warnings being treated as errors
> > mv: cannot stat '/tmp/build/perf/util/.session.o.tmp': No such file or directory
> > make[4]: *** [/home/acme/git/perf/tools/build/Makefile.build:96: /tmp/build/perf/util/session.o] Error 1
> > make[3]: *** [/home/acme/git/perf/tools/build/Makefile.build:139: util] Error 2
> > make[2]: *** [Makefile.perf:559: /tmp/build/perf/perf-in.o] Error 2
> > make[1]: *** [Makefile.perf:215: sub-make] Error 2
> > make: *** [Makefile:110: install-bin] Error 2
> > make: Leaving directory '/home/acme/git/perf/tools/perf'
>
> So, here is your patch:
>
> diff --git a/tools/perf/util/session.c b/tools/perf/util/session.c
> index b17f1c9bc965..e89716175588 100644
> --- a/tools/perf/util/session.c
> +++ b/tools/perf/util/session.c
> @@ -1930,10 +1930,10 @@ reader__process_events(struct reader *rd, struct perf_session *session,
>
> if (size < sizeof(struct perf_event_header) ||
> (skip = rd->process(session, event, file_pos)) < 0) {
> - pr_err("%#" PRIx64 " [%#x]: failed to process type: %d\n",
> + pr_err("%#" PRIx64 " [%#x]: failed to process type: %d [%s]\n",
> file_offset + head, event->header.size,
> - event->header.type);
> - err = -EINVAL;
> + event->header.type, strerror(-skip));
> + err = skip;
> goto out;
> }
>
> [acme@quaco perf]$
>
> What happens if (size < sizeof(struct perf_event_header)) is true? size
> will have an undefined value, so the right thing is to have this patch
> on top of yours, so that err get, as before, set to -EINVAL when the
> size is less than the perf_event_header sizeof:
I'd think you need to squash your change with the original patch
for the bisecting sake, right?
>
> diff --git a/tools/perf/util/session.c b/tools/perf/util/session.c
> index e89716175588..bad5f87ae001 100644
> --- a/tools/perf/util/session.c
> +++ b/tools/perf/util/session.c
> @@ -1928,6 +1928,8 @@ reader__process_events(struct reader *rd, struct perf_session *session,
>
> size = event->header.size;
>
> + skip = -EINVAL;
> +
> if (size < sizeof(struct perf_event_header) ||
> (skip = rd->process(session, event, file_pos)) < 0) {
> pr_err("%#" PRIx64 " [%#x]: failed to process type: %d [%s]\n",
>
> ---
>
> With two Reviewed-by tags, I jumped to quickly at applying, please
> compile test next time guys ;-) :-)
ugh.. need to slow down, this is happening too often now :-\
jirka
Em Fri, Apr 26, 2019 at 04:44:06PM +0200, Jiri Olsa escreveu:
> On Fri, Apr 26, 2019 at 11:16:07AM -0300, Arnaldo Carvalho de Melo wrote:
>
> SNIP
>
> > > util/session.c: In function ‘perf_session__process_events’:
> > > util/session.c:1936:7: error: ‘skip’ may be used uninitialized in this function [-Werror=maybe-uninitialized]
> > > err = skip;
> > > ~~~~^~~~~~
> > > util/session.c:1874:6: note: ‘skip’ was declared here
> > > s64 skip;
> > > ^~~~
> > > cc1: all warnings being treated as errors
> > > mv: cannot stat '/tmp/build/perf/util/.session.o.tmp': No such file or directory
> > > make[4]: *** [/home/acme/git/perf/tools/build/Makefile.build:96: /tmp/build/perf/util/session.o] Error 1
> > > make[3]: *** [/home/acme/git/perf/tools/build/Makefile.build:139: util] Error 2
> > > make[2]: *** [Makefile.perf:559: /tmp/build/perf/perf-in.o] Error 2
> > > make[1]: *** [Makefile.perf:215: sub-make] Error 2
> > > make: *** [Makefile:110: install-bin] Error 2
> > > make: Leaving directory '/home/acme/git/perf/tools/perf'
> >
> > So, here is your patch:
> >
> > diff --git a/tools/perf/util/session.c b/tools/perf/util/session.c
> > index b17f1c9bc965..e89716175588 100644
> > --- a/tools/perf/util/session.c
> > +++ b/tools/perf/util/session.c
> > @@ -1930,10 +1930,10 @@ reader__process_events(struct reader *rd, struct perf_session *session,
> >
> > if (size < sizeof(struct perf_event_header) ||
> > (skip = rd->process(session, event, file_pos)) < 0) {
> > - pr_err("%#" PRIx64 " [%#x]: failed to process type: %d\n",
> > + pr_err("%#" PRIx64 " [%#x]: failed to process type: %d [%s]\n",
> > file_offset + head, event->header.size,
> > - event->header.type);
> > - err = -EINVAL;
> > + event->header.type, strerror(-skip));
> > + err = skip;
> > goto out;
> > }
> >
> > [acme@quaco perf]$
> >
> > What happens if (size < sizeof(struct perf_event_header)) is true? size
> > will have an undefined value, so the right thing is to have this patch
> > on top of yours, so that err get, as before, set to -EINVAL when the
> > size is less than the perf_event_header sizeof:
>
> I'd think you need to squash your change with the original patch
> for the bisecting sake, right?
Yes, that is what I did.
> > +++ b/tools/perf/util/session.c
> > @@ -1928,6 +1928,8 @@ reader__process_events(struct reader *rd, struct perf_session *session,
> >
> > size = event->header.size;
> >
> > + skip = -EINVAL;
> > +
> > if (size < sizeof(struct perf_event_header) ||
> > (skip = rd->process(session, event, file_pos)) < 0) {
> > pr_err("%#" PRIx64 " [%#x]: failed to process type: %d [%s]\n",
> >
> > ---
> >
> > With two Reviewed-by tags, I jumped to quickly at applying, please
> > compile test next time guys ;-) :-)
> ugh.. need to slow down, this is happening too often now :-\
Right, I'll test build everything, and I do like reviewers, who don't?
Its just that when I see reviewed-by tags I end up relaxing a bit :-)
- Arnaldo
Commit-ID: 167e418fa0871c083e2c74508d73012abb01e6f7
Gitweb: https://git.kernel.org/tip/167e418fa0871c083e2c74508d73012abb01e6f7
Author: Thomas Richter <[email protected]>
AuthorDate: Tue, 23 Apr 2019 12:53:03 +0200
Committer: Arnaldo Carvalho de Melo <[email protected]>
CommitDate: Thu, 2 May 2019 16:00:20 -0400
perf report: Report OOM in status line in the GTK UI
An -ENOMEM error is not reported in the GTK GUI. Instead this error
message pops up on the screen:
[root@m35lp76 perf]# ./perf report -i perf.data.error68-1
Processing events... [974K/3M]
Error:failed to process sample
0xf4198 [0x8]: failed to process type: 68
However when I use the same perf.data file with --stdio it works:
[root@m35lp76 perf]# ./perf report -i perf.data.error68-1 --stdio \
| head -12
# Total Lost Samples: 0
#
# Samples: 76K of event 'cycles'
# Event count (approx.): 99056160000
#
# Overhead Command Shared Object Symbol
# ........ ............... ................. .........
#
8.81% find [kernel.kallsyms] [k] ftrace_likely_update
8.74% swapper [kernel.kallsyms] [k] ftrace_likely_update
8.34% sshd [kernel.kallsyms] [k] ftrace_likely_update
2.19% kworker/u512:1- [kernel.kallsyms] [k] ftrace_likely_update
The sample precentage is a bit low.....
The GUI always fails in the FINISHED_ROUND event (68) and does not
indicate the reason why.
When happened is the following. Perf report calls a lot of functions and
down deep when a FINISHED_ROUND event is processed, these functions are
called:
perf_session__process_event()
+ perf_session__process_user_event()
+ process_finished_round()
+ ordered_events__flush()
+ __ordered_events__flush()
+ do_flush()
+ ordered_events__deliver_event()
+ perf_session__deliver_event()
+ machine__deliver_event()
+ perf_evlist__deliver_event()
+ process_sample_event()
+ hist_entry_iter_add() --> only called in GUI case!!!
+ hist_iter__report__callback()
+ symbol__inc_addr_sample()
Now this functions runs out of memory and
returns -ENOMEM. This is reported all the way up
until function
perf_session__process_event() returns to its caller, where -ENOMEM is
changed to -EINVAL and processing stops:
if ((skip = perf_session__process_event(session, event, head)) < 0) {
pr_err("%#" PRIx64 " [%#x]: failed to process type: %d\n",
head, event->header.size, event->header.type);
err = -EINVAL;
goto out_err;
}
This occurred in the FINISHED_ROUND event when it has to process some
10000 entries and ran out of memory.
This patch indicates the root cause and displays it in the status line
of ther perf report GUI.
Output before (on GUI status line):
0xf4198 [0x8]: failed to process type: 68
Output after:
0xf4198 [0x8]: failed to process type: 68 [not enough memory]
Committer notes:
the 'skip' variable needs to be initialized to -EINVAL, so that when the
size is less than sizeof(struct perf_event_attr) we avoid this valid
compiler warning:
util/session.c: In function ‘perf_session__process_events’:
util/session.c:1936:7: error: ‘skip’ may be used uninitialized in this function [-Werror=maybe-uninitialized]
err = skip;
~~~~^~~~~~
util/session.c:1874:6: note: ‘skip’ was declared here
s64 skip;
^~~~
cc1: all warnings being treated as errors
Signed-off-by: Thomas Richter <[email protected]>
Reviewed-by: Hendrik Brueckner <[email protected]>
Reviewed-by: Jiri Olsa <[email protected]>
Cc: Heiko Carstens <[email protected]>
Cc: Martin Schwidefsky <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
---
tools/perf/util/session.c | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)
diff --git a/tools/perf/util/session.c b/tools/perf/util/session.c
index b17f1c9bc965..bad5f87ae001 100644
--- a/tools/perf/util/session.c
+++ b/tools/perf/util/session.c
@@ -1928,12 +1928,14 @@ more:
size = event->header.size;
+ skip = -EINVAL;
+
if (size < sizeof(struct perf_event_header) ||
(skip = rd->process(session, event, file_pos)) < 0) {
- pr_err("%#" PRIx64 " [%#x]: failed to process type: %d\n",
+ pr_err("%#" PRIx64 " [%#x]: failed to process type: %d [%s]\n",
file_offset + head, event->header.size,
- event->header.type);
- err = -EINVAL;
+ event->header.type, strerror(-skip));
+ err = skip;
goto out;
}