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| author | Andrew Vagin <avagin@openvz.org> | 2012-07-11 18:14:58 +0400 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2012-07-31 17:02:05 +0200 |
| commit | e6dab5ffab59e910ec0e3355f4a6f29f7a7be474 (patch) | |
| tree | 87acf0fb071b8d09794ac7d834cb256de030cceb /kernel/events/callchain.c | |
| parent | d07bdfd322d307789f15b427dbcc39257665356f (diff) | |
| download | talos-obmc-linux-e6dab5ffab59e910ec0e3355f4a6f29f7a7be474.tar.gz talos-obmc-linux-e6dab5ffab59e910ec0e3355f4a6f29f7a7be474.zip | |
perf/trace: Add ability to set a target task for events
A few events are interesting not only for a current task.
For example, sched_stat_* events are interesting for a task
which wakes up. For this reason, it will be good if such
events will be delivered to a target task too.
Now a target task can be set by using __perf_task().
The original idea and a draft patch belongs to Peter Zijlstra.
I need these events for profiling sleep times. sched_switch is used for
getting callchains and sched_stat_* is used for getting time periods.
These events are combined in user space, then it can be analyzed by
perf tools.
Inspired-by: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Arun Sharma <asharma@fb.com>
Signed-off-by: Andrew Vagin <avagin@openvz.org>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1342016098-213063-1-git-send-email-avagin@openvz.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel/events/callchain.c')
| -rw-r--r-- | kernel/events/callchain.c | 9 |
1 files changed, 8 insertions, 1 deletions
diff --git a/kernel/events/callchain.c b/kernel/events/callchain.c index 6581a040f399..98d4597f43d6 100644 --- a/kernel/events/callchain.c +++ b/kernel/events/callchain.c @@ -153,7 +153,8 @@ put_callchain_entry(int rctx) put_recursion_context(__get_cpu_var(callchain_recursion), rctx); } -struct perf_callchain_entry *perf_callchain(struct pt_regs *regs) +struct perf_callchain_entry * +perf_callchain(struct perf_event *event, struct pt_regs *regs) { int rctx; struct perf_callchain_entry *entry; @@ -178,6 +179,12 @@ struct perf_callchain_entry *perf_callchain(struct pt_regs *regs) } if (regs) { + /* + * Disallow cross-task user callchains. + */ + if (event->ctx->task && event->ctx->task != current) + goto exit_put; + perf_callchain_store(entry, PERF_CONTEXT_USER); perf_callchain_user(entry, regs); } |
