Instruction tracing options (i.e. --itrace) include an option for
sampling instructions at an arbitrary period. e.g.
--itrace=i10us
means make an 'instructions' sample for every 10us of trace.
Currently the logic does not distinguish between a period of
zero and no period being specified at all, so it gets treated
as the default period which is 100000. That doesn't really
make sense.
Fix it so that zero period is accepted and treated as meaning
"as often as possible".
In the case of Intel PT that is the same as a period of 1 and
a unit of 'instructions' (i.e. --itrace=i1i).
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/r/1443186956-18718-2-git-send-email-adrian.hunter@intel.com
[ Add a few lines describing this in the Documentation/intel-pt.txt file ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
User visible:
- Use PERF_RECORD_SWITCH when available in intel-pt, instead of
"sched:sched_switch" events, enabling an unprivileged user to trace
multi-threaded or multi-process workloads (Adrian Hunter)
- Always use non inlined file name for 'srcfile' sort key (Andi Kleen)
- Quieten failed to read counter message, helps in systems without
backend-stalled-cycles (Andi Kleen)
Infrastructure:
- Add a 'perf test' entry for decoding of new x86 instructions (Adrian Hunter)
- Add new instructions (sha, clflushopt, clwb, pcommit, rdpkru, wrpkru, xsavec,
xsaves, xrstors) to the x86 instruction decoder (Adrian Hunter)
- Add a build test to warn when source code drifts happen for the
instruction decoder files in the kernel and in tools/perf (Adrian Hunter)
- Copy linux/filter.h to tools/include (He Kuang)
- Support function __get_dynamic_array_len in libtraceevent (He Kuanguuu)
- Tracing path finding/mounting/error reporting refactorings (Jiri Olsa)
- Store CPU socket and core IDs in perf.data (Kan Liang)
- Reorganize add/del probe insertion routines in 'perf probe' (Namhyung Kim, Wang Nan)
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
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Merge tag 'perf-core-for-mingo' of git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux into perf/core
Pull perf/core improvements and fixes from Arnaldo Carvalho de Melo:
User visible changes:
- Use PERF_RECORD_SWITCH when available in intel-pt, instead of
"sched:sched_switch" events, enabling an unprivileged user to trace
multi-threaded or multi-process workloads. (Adrian Hunter)
- Always use non inlined file name for 'srcfile' sort key. (Andi Kleen)
- Quieten failed to read counter message, helps in systems without
backend-stalled-cycles. (Andi Kleen)
Infrastructure changes:
- Add a 'perf test' entry for decoding of new x86 instructions. (Adrian Hunter)
- Add new instructions (sha, clflushopt, clwb, pcommit, rdpkru, wrpkru, xsavec,
xsaves, xrstors) to the x86 instruction decoder. (Adrian Hunter)
- Add a build test to warn when source code drifts happen for the
instruction decoder files in the kernel and in tools/perf. (Adrian Hunter)
- Copy linux/filter.h to tools/include. (He Kuang)
- Support function __get_dynamic_array_len in libtraceevent. (He Kuanguuu)
- Tracing path finding/mounting/error reporting refactorings. (Jiri Olsa)
- Store CPU socket and core IDs in perf.data. (Kan Liang)
- Reorganize add/del probe insertion routines in 'perf probe'. (Namhyung Kim, Wang Nan)
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Add support for selecting and processing PERF_RECORD_SWITCH events for
use by Intel PT. If they are available, they will be used in preference
to sched_switch events.
This enables an unprivileged user to trace multi-threaded or
multi-process workloads with any level of perf_event_paranoid. However
it depends on kernel support for PERF_RECORD_SWITCH.
Without this patch, tracing a multi-threaded workload will decode
without error but all the data will be attributed to the main thread.
Without this patch, tracing a multi-process workload will result in
decoder errors because the decoder will not know which executable is
executing.
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/r/1439458857-30636-3-git-send-email-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
In a couple of cases the 'comm' member of 'union event' has been used
instead of the correct member ('fork') when processing exit events.
In the cases where it has been used incorrectly, only the 'pid' and
'tid' are affected. The 'pid' value would be correct anyway because it
is in the same position in 'comm' and 'fork' events, but the 'tid' would
have been incorrectly assigned from 'ppid'.
However, for exit events, the kernel puts the current task in the 'ppid'
and 'ttid' which is the same as the exiting task. That is 'ppid' ==
'pid' and if the task is not multi-threaded, 'pid' == 'tid' i.e. the
data goes wrong only when tracing multi-threaded programs.
It is hard to find an example of how this would produce an error in
practice. There are 3 occurences of the fix:
1. perf script is only affected if !sample_id_all which only happens on
old kernels.
2. intel_pt is only affected when decoding without timestamps
and would probably still decode correctly - the exit event is
only used to flush out data which anyway gets flushed at the
end of the session
3. intel_bts also uses the exit event to flush data which
would probably not cause errors as it would get flushed at
the end of the session instead
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/r/1439888825-27708-1-git-send-email-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Record additional information in the AUXTRACE_INFO event in preparation
for decoding MTC and CYC packets. Pass the information to the decoder.
The AUXTRACE_INFO record can be extended by using the size to indicate
the presence of new members.
The additional information includes PMU config bit positions and the TSC
to CTC (hardware crystal clock) ratio needed to decode MTC packets.
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/r/1437150840-31811-20-git-send-email-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
The period on synthesized 'instructions' samples was being set to a
fixed value, whereas the correct value is the number of instructions
since the last sample, which is a value that the decoder can provide.
So do it that way.
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/r/1437150840-31811-14-git-send-email-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Events that don't sample the timestamp have a timestamp value of -1.
Intel PT processing wasn't taking that into account.
This is particularly noticeable with Intel BTS because timestamps are
not requested by default.
Then, if the conversion of -1 to TSC results in a small number, the
processing is unaffected.
However if the conversion results in a big number, then the data is
processed prematurely before relevant sideband data like mmap events,
which in turn results in samples with unknown dsos.
Commiter note:
Since BTS wasn't upstream, I split the patch to fold the BTS part with
the patch introducing it, to avoid having this bug in the commit
history. PT was already upstream, so this patch contains that part.
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/r/1440060692-5585-1-git-send-email-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Add support for Intel Processor Trace.
Intel PT support fits within the new auxtrace infrastructure. Recording
is supporting by identifying the Intel PT PMU, parsing options and
setting up events.
Decoding is supported by queuing up trace data by cpu or thread and then
decoding synchronously delivering synthesized event samples into the
session processing for tools to consume.
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/r/1437150840-31811-7-git-send-email-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Adrian Hunter