Messages in this thread | | | Date | Wed, 25 Mar 2015 10:11:47 +0100 | From | Ingo Molnar <> | Subject | Re: [PATCH] perf record: Allow poll timeout to be specified |
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* Arnaldo Carvalho de Melo <acme@kernel.org> wrote:
> Em Tue, Mar 24, 2015 at 05:12:11PM +0100, Ingo Molnar escreveu: > > * David Ahern <david.ahern@oracle.com> wrote: > > > > > Record currently wakes up based on watermarks to read events > > > from the mmaps and write them out to the file. The result is a > > > file that can have large blocks of events per mmap before a > > > finished round event is added to the stream. This in turn > > > affects the quantity of events that have to be passed through > > > the ordered events queue before results can be displayed to the > > > user. For commands like perf-script this can lead to long > > > unnecessarily long delays before a user gets output. Large > > > systems (e.g, 1024 cpus) further compound this effect. I have > > > seen instances where I have to wait 45 minutes for perf-script > > > to process a 5GB file before any events are shown. > > > > > > This patch adds an option to perf-record to allow a user to > > > specify the poll timeout in msec. For example using 100 msec > > > timeouts similar to perf-top means the mmaps are traversed much > > > more frequently leading to a smoother analysis side. > > > > Please tune the default value (perhaps influenced by N_PROC?) so > > that users will get sane behavior without having to specify this > > option! > > Isn't this a followup patch? [...]
Will a followup patch be written?
Thanks,
Ingo
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