From: Adrian Hunter <[email protected]>
Document how to select PEBS via Intel PT and how to display synthesized
PEBS samples.
Signed-off-by: Adrian Hunter <[email protected]>
Signed-off-by: Alexander Shishkin <[email protected]>
---
tools/perf/Documentation/intel-pt.txt | 15 +++++++++++++++
1 file changed, 15 insertions(+)
diff --git a/tools/perf/Documentation/intel-pt.txt b/tools/perf/Documentation/intel-pt.txt
index 50c5b60101bd..8dc513b6607b 100644
--- a/tools/perf/Documentation/intel-pt.txt
+++ b/tools/perf/Documentation/intel-pt.txt
@@ -919,3 +919,18 @@ amended to take the number of elements as a parameter.
Note there is currently no advantage to using Intel PT instead of LBR, but
that may change in the future if greater use is made of the data.
+
+
+PEBS via Intel PT
+=================
+
+Some hardware has the feature to redirect PEBS records to the Intel PT trace.
+Recording is selected by using the aux-output config term e.g.
+
+ perf record -c 10000 -e cycles/aux-output/ppp -e intel_pt/branch=0/ uname
+
+Note that currently, software only supports redirecting at most one PEBS event.
+
+To display PEBS events from the Intel PT trace, use the itrace 'o' option e.g.
+
+ perf script --itrace=oe
--
2.20.1
Em Tue, Aug 13, 2019 at 05:05:46PM +0300, Alexander Shishkin escreveu:
> Arnaldo Carvalho de Melo <[email protected]> writes:
>
> > Em Tue, Aug 06, 2019 at 11:46:06AM +0300, Alexander Shishkin escreveu:
> >> From: Adrian Hunter <[email protected]>
> >>
> >> Document how to select PEBS via Intel PT and how to display synthesized
> >> PEBS samples.
> >>
> >> Signed-off-by: Adrian Hunter <[email protected]>
> >> Signed-off-by: Alexander Shishkin <[email protected]>
> >> ---
> >> tools/perf/Documentation/intel-pt.txt | 15 +++++++++++++++
> >> 1 file changed, 15 insertions(+)
> >>
> >> diff --git a/tools/perf/Documentation/intel-pt.txt b/tools/perf/Documentation/intel-pt.txt
> >> index 50c5b60101bd..8dc513b6607b 100644
> >> --- a/tools/perf/Documentation/intel-pt.txt
> >> +++ b/tools/perf/Documentation/intel-pt.txt
> >> @@ -919,3 +919,18 @@ amended to take the number of elements as a parameter.
> >>
> >> Note there is currently no advantage to using Intel PT instead of LBR, but
> >> that may change in the future if greater use is made of the data.
> >> +
> >> +
> >> +PEBS via Intel PT
> >> +=================
> >> +
> >> +Some hardware has the feature to redirect PEBS records to the Intel PT trace.
> >> +Recording is selected by using the aux-output config term e.g.
> >> +
> >> + perf record -c 10000 -e cycles/aux-output/ppp -e intel_pt/branch=0/ uname
> >> +
> >> +Note that currently, software only supports redirecting at most one PEBS event.
> >
> > So, with these patches, but not the kernel ones I end up getting:
> >
> > [root@quaco ~]# perf record -c 10000 -e cycles/aux-output/ppp -e intel_pt/branch=0/ uname
>
> FWIW, the correct command line for that would have the two events
> grouped and intel_pt be the group leader.
I've just blindly followed the provided documentation :)
So you say I should have tried this instead:
# perf record -c 10000 -e '{intel_pt/branch=0/,cycles/aux-output/ppp}' uname
Error:
The 'aux_output' feature is not supported, update the kernel.
#
Or with leader sampling?
# perf record -c 10000 -e '{intel_pt/branch=0/,cycles/aux-output/ppp}:S' uname
Error:
The 'aux_output' feature is not supported, update the kernel.
#
This is with the patch at the end of this message and without the kernel counterpart.
- Arnaldo
commit 58c5a9772d88f5dead1e561f6323f9f355625caa
Author: Arnaldo Carvalho de Melo <[email protected]>
Date: Tue Aug 13 11:06:38 2019 -0300
perf evsel: Provide meaningful warning when trying to use 'aux_output' on older kernels
Just like we do with the 'write_backwards' feature:
Before:
# perf record -c 10000 -e cycles/aux-output/ppp -e intel_pt/branch=0/ uname
Error:
The sys_perf_event_open() syscall returned with 22 (Invalid argument) for event (cycles/aux-output/ppp).
/bin/dmesg | grep -i perf may provide additional information.
#
After:
# perf record -c 10000 -e cycles/aux-output/ppp -e intel_pt/branch=0/ uname
Error:
The 'aux_output' feature is not supported, update the kernel.
#
Cc: Adrian Hunter <[email protected]>
Cc: Alexander Shishkin <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Kan Liang <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Link: https://lkml.kernel.org/n/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c
index 6f08aea4f108..0b3b5af33954 100644
--- a/tools/perf/util/evsel.c
+++ b/tools/perf/util/evsel.c
@@ -1738,7 +1738,8 @@ int evsel__open(struct evsel *evsel, struct perf_cpu_map *cpus,
int pid = -1, err;
enum { NO_CHANGE, SET_TO_MAX, INCREASED_MAX } set_rlimit = NO_CHANGE;
- if (perf_missing_features.write_backward && evsel->core.attr.write_backward)
+ if ((perf_missing_features.write_backward && evsel->core.attr.write_backward) ||
+ (perf_missing_features.aux_output && evsel->core.attr.aux_output))
return -EINVAL;
if (cpus == NULL) {
@@ -1912,7 +1913,11 @@ int evsel__open(struct evsel *evsel, struct perf_cpu_map *cpus,
* Must probe features in the order they were added to the
* perf_event_attr interface.
*/
- if (!perf_missing_features.bpf_event && evsel->core.attr.bpf_event) {
+ if (!perf_missing_features.aux_output && evsel->core.attr.aux_output) {
+ perf_missing_features.aux_output = true;
+ pr_debug2("Kernel has no attr.aux_output support, bailing out\n");
+ goto out_close;
+ } else if (!perf_missing_features.bpf_event && evsel->core.attr.bpf_event) {
perf_missing_features.bpf_event = true;
pr_debug2("switching off bpf_event\n");
goto fallback_missing_features;
@@ -2926,6 +2931,8 @@ int perf_evsel__open_strerror(struct evsel *evsel, struct target *target,
return scnprintf(msg, size, "clockid feature not supported.");
if (perf_missing_features.clockid_wrong)
return scnprintf(msg, size, "wrong clockid (%d).", clockid);
+ if (perf_missing_features.aux_output)
+ return scnprintf(msg, size, "The 'aux_output' feature is not supported, update the kernel.");
break;
default:
break;
diff --git a/tools/perf/util/evsel.h b/tools/perf/util/evsel.h
index 8a316dd54cd0..9cd6e3ae479a 100644
--- a/tools/perf/util/evsel.h
+++ b/tools/perf/util/evsel.h
@@ -184,6 +184,7 @@ struct perf_missing_features {
bool group_read;
bool ksymbol;
bool bpf_event;
+ bool aux_output;
};
extern struct perf_missing_features perf_missing_features;
Em Tue, Aug 06, 2019 at 11:46:06AM +0300, Alexander Shishkin escreveu:
> From: Adrian Hunter <[email protected]>
>
> Document how to select PEBS via Intel PT and how to display synthesized
> PEBS samples.
>
> Signed-off-by: Adrian Hunter <[email protected]>
> Signed-off-by: Alexander Shishkin <[email protected]>
> ---
> tools/perf/Documentation/intel-pt.txt | 15 +++++++++++++++
> 1 file changed, 15 insertions(+)
>
> diff --git a/tools/perf/Documentation/intel-pt.txt b/tools/perf/Documentation/intel-pt.txt
> index 50c5b60101bd..8dc513b6607b 100644
> --- a/tools/perf/Documentation/intel-pt.txt
> +++ b/tools/perf/Documentation/intel-pt.txt
> @@ -919,3 +919,18 @@ amended to take the number of elements as a parameter.
>
> Note there is currently no advantage to using Intel PT instead of LBR, but
> that may change in the future if greater use is made of the data.
> +
> +
> +PEBS via Intel PT
> +=================
> +
> +Some hardware has the feature to redirect PEBS records to the Intel PT trace.
> +Recording is selected by using the aux-output config term e.g.
> +
> + perf record -c 10000 -e cycles/aux-output/ppp -e intel_pt/branch=0/ uname
> +
> +Note that currently, software only supports redirecting at most one PEBS event.
So, with these patches, but not the kernel ones I end up getting:
[root@quaco ~]# perf record -c 10000 -e cycles/aux-output/ppp -e intel_pt/branch=0/ uname
Error:
The sys_perf_event_open() syscall returned with 22 (Invalid argument)
for event (cycles/aux-output/ppp).
/bin/dmesg | grep -i perf may provide additional information.
[root@quaco ~]#
I'll check if I can make it spew a more helpful message, then build a
kernel with the kernel patches and try with it as well.
PeterZ has the kernel ones landed on tip? I guess not, as perf/core I
have should be in sync...
- Arnaldo
> +To display PEBS events from the Intel PT trace, use the itrace 'o' option e.g.
> +
> + perf script --itrace=oe
> --
> 2.20.1
Arnaldo Carvalho de Melo <[email protected]> writes:
> Em Tue, Aug 06, 2019 at 11:46:06AM +0300, Alexander Shishkin escreveu:
>> From: Adrian Hunter <[email protected]>
>>
>> Document how to select PEBS via Intel PT and how to display synthesized
>> PEBS samples.
>>
>> Signed-off-by: Adrian Hunter <[email protected]>
>> Signed-off-by: Alexander Shishkin <[email protected]>
>> ---
>> tools/perf/Documentation/intel-pt.txt | 15 +++++++++++++++
>> 1 file changed, 15 insertions(+)
>>
>> diff --git a/tools/perf/Documentation/intel-pt.txt b/tools/perf/Documentation/intel-pt.txt
>> index 50c5b60101bd..8dc513b6607b 100644
>> --- a/tools/perf/Documentation/intel-pt.txt
>> +++ b/tools/perf/Documentation/intel-pt.txt
>> @@ -919,3 +919,18 @@ amended to take the number of elements as a parameter.
>>
>> Note there is currently no advantage to using Intel PT instead of LBR, but
>> that may change in the future if greater use is made of the data.
>> +
>> +
>> +PEBS via Intel PT
>> +=================
>> +
>> +Some hardware has the feature to redirect PEBS records to the Intel PT trace.
>> +Recording is selected by using the aux-output config term e.g.
>> +
>> + perf record -c 10000 -e cycles/aux-output/ppp -e intel_pt/branch=0/ uname
>> +
>> +Note that currently, software only supports redirecting at most one PEBS event.
>
> So, with these patches, but not the kernel ones I end up getting:
>
> [root@quaco ~]# perf record -c 10000 -e cycles/aux-output/ppp -e intel_pt/branch=0/ uname
FWIW, the correct command line for that would have the two events
grouped and intel_pt be the group leader.
Regards,
--
Alex
Arnaldo Carvalho de Melo <[email protected]> writes:
> I've just blindly followed the provided documentation :)
Yes, I should have checked it also before I sent it out. :)
> So you say I should have tried this instead:
>
> # perf record -c 10000 -e '{intel_pt/branch=0/,cycles/aux-output/ppp}' uname
Right. For the purposes of illustrating the error condition, you can
probably drop the '-c ...' and 'branch=0' also, but either way is fine.
> Error:
> The 'aux_output' feature is not supported, update the kernel.
Or it's not supported by the hardware. I don't think we make a
distinction at the moment. You can tell if it's available from dmesg,
but not otherwise.
> #
>
> Or with leader sampling?
>
> # perf record -c 10000 -e '{intel_pt/branch=0/,cycles/aux-output/ppp}:S' uname
Not sure if we should even allow this. Maybe Adrian can chime in.
Thanks,
--
Alex
Commit-ID: 243384dd25c8ea721c5c82a229eaf33cbd1bfd52
Gitweb: https://git.kernel.org/tip/243384dd25c8ea721c5c82a229eaf33cbd1bfd52
Author: Adrian Hunter <[email protected]>
AuthorDate: Tue, 6 Aug 2019 11:46:06 +0300
Committer: Arnaldo Carvalho de Melo <[email protected]>
CommitDate: Wed, 14 Aug 2019 10:59:59 -0300
perf intel-pt: Add brief documentation for PEBS via Intel PT
Document how to select PEBS via Intel PT and how to display synthesized
PEBS samples.
Signed-off-by: Adrian Hunter <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Kan Liang <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Alexander Shishkin <[email protected]>
[ Update the example to use a group with intel_pt// as the group leader, as per Alex comment ]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
---
tools/perf/Documentation/intel-pt.txt | 15 +++++++++++++++
1 file changed, 15 insertions(+)
diff --git a/tools/perf/Documentation/intel-pt.txt b/tools/perf/Documentation/intel-pt.txt
index 50c5b60101bd..e0d9e7dd4f17 100644
--- a/tools/perf/Documentation/intel-pt.txt
+++ b/tools/perf/Documentation/intel-pt.txt
@@ -919,3 +919,18 @@ amended to take the number of elements as a parameter.
Note there is currently no advantage to using Intel PT instead of LBR, but
that may change in the future if greater use is made of the data.
+
+
+PEBS via Intel PT
+=================
+
+Some hardware has the feature to redirect PEBS records to the Intel PT trace.
+Recording is selected by using the aux-output config term e.g.
+
+ perf record -c 10000 -e '{intel_pt/branch=0/,cycles/aux-output/ppp}' uname
+
+Note that currently, software only supports redirecting at most one PEBS event.
+
+To display PEBS events from the Intel PT trace, use the itrace 'o' option e.g.
+
+ perf script --itrace=oe