Messages in this thread |  | | | Subject | Re: [patch 0/4] perf_counter tools: support annotation of live kernel modules | | From | Mike Galbraith <> | | Date | Thu, 02 Jul 2009 09:55:42 +0200 |
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On Thu, 2009-07-02 at 09:42 +0200, Ingo Molnar wrote:
(squirrels suggestions away for later reference)
> Btw, another thing: we are thinking about making -F 1000 (1 KHz > auto-freq sampling) the default for perf top and perf record. This > way we'd always gather enough data (and never too much or too little > data), regardless of the intensity of the workload. Have you played > with -F before, what's your general experience about it? It's > particularly useful for 'rare' and highly fluctuating events like > cache-misses. > > Maybe 1KHz is a bit too low - Oprofile defaults to 100000 cycles > interval by default which is about 10 KHz on a 1GHz box and 30 KHz > on a 3GHz box. Perhaps 10 KHz is a better default?
My default usage is 1000Hz to keep overhead low. Works fine for me.
-Mike
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