Messages in this thread | | | Date | Tue, 24 Mar 2015 18:21:20 -0300 | From | Arnaldo Carvalho de Melo <> | Subject | Re: [PATCH] perf record: Allow poll timeout to be specified |
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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? I.e. changing the default from infinity to some sane value?
Applying it now.
- Arnaldo
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