lkml.org 
[lkml]   [2015]   [Mar]   [24]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH] perf record: Allow poll timeout to be specified
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


\
 
 \ /
  Last update: 2015-03-24 22:41    [W:0.094 / U:0.144 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site