Messages in this thread | | | Date | Wed, 25 Nov 2015 13:20:38 +0100 | From | Peter Zijlstra <> | Subject | Re: [PATCH] perf record: Add snapshot mode support for perf's regular events |
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On Wed, Nov 25, 2015 at 05:44:00PM +0800, Wangnan (F) wrote: > > > On 2015/11/25 17:27, Peter Zijlstra wrote: > >On Tue, Nov 24, 2015 at 10:00:31PM +0800, Yunlong Song wrote: > >>In our patch, we create and maintain a user space ring buffer to store > >>perf's tracing info, instead of directly writing to perf.data file as > >>before. In snapshot mode, only a SIGUSR2 signal can trigger perf to dump > >>the tracing info currently stored in the user space ring buffer to > >>perf.data file. > >I would very much like to first fix the perf overwrite mode: see > >lkml.kernel.org/r/20151023151205.GW11639@twins.programming.kicks-ass.net > > I think they can be done in parallel. We can first do something with > tracking events and perf's output file, and wait for kernel level > overwrite mode fixed, then decide whether to implement perf's own > ringbuffer.
That seems backwards; why would you ever want to endlessly copy the events if you're not going to use them?
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