On Wed, 16 Mar 2016 15:34:31 +0100 Jiri Olsa <[email protected]> wrote:
> Having following commands running concurrently: > > # perf record -e ftrace:function -a -o krava.data sleep 10 > # perf record -e ftrace:function --filter 'ip == SyS_read' ls > > will end up in the latter one to fail on the filter rules > and store all functions (in perf.data) as instructed by the > first perf record instead of just SyS_read records. > > The reason for this is, that tracepoint code by default > triggers all events that registered for the tracepoint. > > While ftrace:function is special because ftrace_ops > itself carries a filter and only the event that owns > ftrace_ops is eligible to be triggered. > > Fixing this by using ftrace_ops::private value to keep > the perf_event pointer. This way we don't need to search > for triggered event (as tracepoint handler does) and > directly store sample. > > Acked-by: Namhyung Kim <[email protected]> > Suggested-by: Steven Rostedt <[email protected]> > Signed-off-by: Jiri Olsa <[email protected]> Acked-by: Steven Rostedt <[email protected]> -- Steve
