Messages in this thread | | | Date | Thu, 5 Jul 2012 21:38:46 +0800 | Subject | Re: [PATCH] perf: add /proc/perf_events file for dump perf events info | From | Jovi Zhang <> |
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On Thu, Jul 5, 2012 at 9:08 PM, Peter Zijlstra <a.p.zijlstra@chello.nl> wrote: > On Thu, 2012-07-05 at 21:02 +0800, Jovi Zhang wrote: >> > Watch all perf events in system wide can be very useful for perf subsystem issue handling, >> > to know which perf event is active in system, >> > perf event is a resouce, it would like to be managed easily for user, with more visable, like /proc/timer, etc... >> > >> > .jovi >> >> >> Ping... > > Never saw your reply, due to HTML it landed in the spam folder. > > That's a pretty non-specific answer.. again, why are you interested, > what specific problem are you wanting to solve. > > I've never had this need myself. > sorry, I will try to explain more.
One problem I faced is about hw_breakpoint. As you known, hw_breakpoint use limit debug register in most architecture, In multi-user environment, sometime user cannot set hw_breakpoint because other user already occupy hw_breakpoint slots. currently, there don't have a way to know how many hw_breakpint perf event already is used in system, so that's why I thinking we might need a way to get perf event in systerm wide, with visable output.
Also this method is not only used for hw_breakpoint, others perf event might have similar problem, even other perf event don't have limit number, but it can make use of this /proc/perf_events
Active perf events is cpu consumer at most time, at this point of view, system administrator also can use this /proc/perf_events to detect is there have any perf events is consuming cpu.
A method to detect perf event leak? of couse our perf subsystem is very stable right now, ingnore this :)
.jovi
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