Messages in this thread | | | Date | Wed, 16 Dec 2009 15:40:52 +0800 | From | Xiao Guangrong <> | Subject | Re: [PATCH 0/4] perf_event: introduce 'perf timer' to analyze timer's behavior |
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Ingo Molnar wrote:
>>> >> Yeah, it has different unit and looks ugly :-( >> >> but, the problem is we can't get HZ in userspace now, i'll export HZ by proc >> or other way and rectify 'perf timer' output in my next work > > We could export HZ as part of the ftrace event format file, in > /debug/tracing/events/timers/ or so. Not sure what the best way would be to do > it (without causing runtime overhead in event processing), but we should > reduce our reliance on /proc and export such instrumentation information via a > single, coherent interface. >
Hi ingo,
Um, if we export this value in tracepoint format, it should add for every timer's tracepoint.
> There's a couple of other 'system settings' values that would be useful to > expose in such a way - for example the number of online CPUs. (in fact that > could be exposed as a set of online/offline events plus a way to read the > current count as well) >
How about export those values in debugfs/tracing/*? perf tracepoint self depend on this filesystem.
Thanks, Xiao
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