* Re: perf can't keep up with mmap data
[not found] <20100719074813.GA418@lst.de>
@ 2010-07-19 15:04 ` Arnaldo Carvalho de Melo
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From: Arnaldo Carvalho de Melo @ 2010-07-19 15:04 UTC (permalink / raw)
To: Christoph Hellwig; +Cc: a.p.zijlstra, paulus, mingo, linux-kernel
Em Mon, Jul 19, 2010 at 09:48:13AM +0200, Christoph Hellwig escreveu:
> When running current -tip perf in my 32-bit x86 kvm guest I get lots
> of messages like:
>
> WARNING: failed to keep up with mmap data.
>
> when starting perf top, and still quite a few everytime it refreshes the
> display.
Should be better reported, probably with a message suggesting to use:
perf top -r RTPRIO
or to reduce the sampling frequency:
perf top -F 500
to have:
PerfTop: 287 irqs/sec kernel:40.8% exact: 0.0% [500Hz cycles], (all, 2 CPUs)
Instead of the default:
PerfTop: 35 irqs/sec kernel:25.7% exact: 0.0% [1000Hz cycles], (all, 2 CPUs)
- Arnaldo
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[not found] <20100719074813.GA418@lst.de>
2010-07-19 15:04 ` perf can't keep up with mmap data Arnaldo Carvalho de Melo
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