linux-stable.git/tools/perf/util/session.c, branch v3.18

perf session: Add option to copy events when queueing

2014-10-15T20:39:03+00:00

When processing events the session code has an ordered samples queue
which is used to time-sort events coming in across multiple mmaps. At a
later point in time samples on the queue are flushed up to some
timestamp at which point the event is actually processed.

When analyzing events live (ie., record/analysis path in the same
command) there is a race that leads to corrupted events and parse errors
which cause perf to terminate. The problem is that when the event is
placed in the ordered samples queue it is only a reference to the event
which is really sitting in the mmap buffer. Even though the event is
queued for later processing the mmap tail pointer is updated which
indicates to the kernel that the event has been processed. The race is
flushing the event from the queue before it gets overwritten by some
other event. For commands trying to process events live (versus just
writing to a file) and processing a high rate of events this leads to
parse failures and perf terminates.

Examples hitting this problem are 'perf kvm stat live', especially with
nested VMs which generate 100,000+ traces per second, and a command
processing scheduling events with a high rate of context switching --
e.g., running 'perf bench sched pipe'.

This patch offers live commands an option to copy the event when it is
placed in the ordered samples queue.

Based on a patch from David Ahern 

Signed-off-by: Alexander Yarygin 
Acked-by: Jiri Olsa 
Cc: Christian Borntraeger 
Cc: David Ahern 
Cc: Frederic Weisbecker 
Cc: Ingo Molnar 
Cc: Jiri Olsa 
Cc: Mike Galbraith 
Cc: Namhyung Kim 
Cc: Paul Mackerras 
Cc: Peter Zijlstra 
Cc: Stephane Eranian 
Link: http://lkml.kernel.org/r/1412347212-28237-2-git-send-email-yarygin@linux.vnet.ibm.com
Signed-off-by: Arnaldo Carvalho de Melo

perf session: Remove last reference to hists struct

2014-10-14T14:41:25+00:00

Now perf_session doesn't require that the evsels in its evlist are hists
containing ones.

Tools that are hists based and want to do per evsel events_stats
updates, if at some point this turns into a necessity, should do it in
the tool specific code, keeping the session class hists agnostic.

Cc: Adrian Hunter 
Cc: Borislav Petkov 
Cc: David Ahern 
Cc: Don Zickus 
Cc: Frederic Weisbecker 
Cc: Jean Pihet 
Cc: Jiri Olsa 
Cc: Mike Galbraith 
Cc: Namhyung Kim 
Cc: Paul Mackerras 
Cc: Peter Zijlstra 
Cc: Stephane Eranian 
Link: http://lkml.kernel.org/n/tip-cli1bgwpo82mdikuhy3djsuy@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo

perf session: Don't count per evsel events

2014-10-10T18:15:32+00:00

PERF_RECORD_SAMPLE was not being counted here and is the only per-evsel
thing anyway, the other events were not mapping to a evsel.

With this we don't require that evsels used with a perf_session need to
have space for hists, like the ones in annotate, report, top.

Cc: Adrian Hunter 
Cc: Borislav Petkov 
Cc: David Ahern 
Cc: Don Zickus 
Cc: Frederic Weisbecker 
Cc: Jean Pihet 
Cc: Jiri Olsa 
Cc: Mike Galbraith 
Cc: Namhyung Kim 
Cc: Paul Mackerras 
Cc: Peter Zijlstra 
Cc: Stephane Eranian 
Link: http://lkml.kernel.org/n/tip-kzchpz0l1mhrsfpkirz086m2@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo

perf evsel: Add hists helper

2014-10-09T16:13:41+00:00

Not all tools need a hists instance per perf_evsel, so lets pave the way
to remove evsel->hists while leaving a way to access the hists from a
specially allocated evsel, one that comes with space at the end where
lives the evsel.

Cc: Adrian Hunter 
Cc: Borislav Petkov 
Cc: David Ahern 
Cc: Don Zickus 
Cc: Frederic Weisbecker 
Cc: Jean Pihet 
Cc: Jiri Olsa 
Cc: Mike Galbraith 
Cc: Namhyung Kim 
Cc: Paul Mackerras 
Cc: Peter Zijlstra 
Cc: Stephane Eranian 
Link: http://lkml.kernel.org/n/tip-qlktkhe31w4mgtbd84035sr2@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo

perf tools: Fix perf record as non root with kptr_restrict == 1

2014-09-26T13:51:41+00:00

Currently perf record always errors out when you run it as non-root with
kptr_restrict == 1, which is often the default.

Make it only warn instead and fix the kernel resolve code to not
segfault later. Profiling works still fine, except kernel symbols are
not resolved.

Signed-off-by: Andi Kleen 
Cc: Ingo Molnar 
Cc: Jiri Olsa 
Cc: Namhyung Kim 
Cc: Peter Zijlstra 
Link: http://lkml.kernel.org/r/1411594794-7229-1-git-send-email-andi@firstfloor.org
Signed-off-by: Arnaldo Carvalho de Melo

perf machine: Add machine__thread_exec_comm()

2014-08-13T22:23:21+00:00

Add machine__thread_exec_comm() to return the comm that matches the last
exec, if the comm_exec flag is present, or the last comm otherwise.

Signed-off-by: Adrian Hunter 
Cc: David Ahern 
Cc: Frederic Weisbecker 
Cc: Jiri Olsa 
Cc: Namhyung Kim 
Cc: Paul Mackerras 
Cc: Peter Zijlstra 
Cc: Stephane Eranian 
Link: http://lkml.kernel.org/r/1406786474-9306-3-git-send-email-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo

perf session: Add perf_session__peek_event()

2014-08-13T22:21:44+00:00

Add a function to peek at other events in the event stream.

Signed-off-by: Adrian Hunter 
Cc: David Ahern 
Cc: Frederic Weisbecker 
Cc: Jiri Olsa 
Cc: Namhyung Kim 
Cc: Paul Mackerras 
Cc: Peter Zijlstra 
Cc: Stephane Eranian 
Link: http://lkml.kernel.org/r/1406786474-9306-15-git-send-email-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo

perf tools: Allow out of order messages in forced flush

2014-08-12T15:03:02+00:00

In forced flush (OE_FLUSH__HALF) we break the rules of the flush
timestamp via PERF_RECORD_FINISHED_ROUND event, so we could get out of
order event.

Do not force error in this case plus changing the output warning to use
WARN_ONCE.

Signed-off-by: Jiri Olsa 
Acked-by: David Ahern 
Cc: Corey Ashford 
Cc: David Ahern 
Cc: Frederic Weisbecker 
Cc: Ingo Molnar 
Cc: Jean Pihet 
Cc: Namhyung Kim 
Cc: Paul Mackerras 
Cc: Peter Zijlstra 
Link: http://lkml.kernel.org/n/tip-8q8794a8nlmpd1u8xrqmcyd2@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo

perf tools: Add debug prints for ordered events queue

2014-08-12T15:03:01+00:00

Adding some prints for ordered events queue, to help debug issues.

Adding debug_ordered_events debug variable to be able to enable ordered
events debug messages using:

  $ perf --debug ordered-events=2 report ...

Also using oe pointer in perf_session__queue_event instead of chained
session variable dereferencing.

Signed-off-by: Jiri Olsa 
Acked-by: David Ahern 
Cc: Corey Ashford 
Cc: David Ahern 
Cc: Frederic Weisbecker 
Cc: Ingo Molnar 
Cc: Jean Pihet 
Cc: Namhyung Kim 
Cc: Paul Mackerras 
Cc: Peter Zijlstra 
Link: http://lkml.kernel.org/n/tip-7p3mnnopjvsp9nmk9msqcfkm@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo

perf tools: Add ordered_events__free function

2014-08-12T15:03:00+00:00

Adding ordered_events__free function to release all the struct
ordered_events data. It's replacement for former
perf_session_free_sample_buffers function.

Signed-off-by: Jiri Olsa 
Acked-by: David Ahern 
Cc: Corey Ashford 
Cc: David Ahern 
Cc: Frederic Weisbecker 
Cc: Ingo Molnar 
Cc: Jean Pihet 
Cc: Namhyung Kim 
Cc: Paul Mackerras 
Cc: Peter Zijlstra 
Link: http://lkml.kernel.org/n/tip-urraa8ccay4o14wambjraws7@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo