Re: [Patch][RFC] Disabling per-tgid stats on task exit in taskstats

Andrew Morton
2006-06-23T21:19:36Z

On Fri, 23 Jun 2006 13:14:41 -0400
Shailabh Nagar <nagar@watson.ibm.com> wrote:

> The results show that differential between tgid on and off
> starts becoming significant once the exit rate crosses roughly 1000
> threads/second. Below that exit rate, the difference is negligible.
> Above it, the difference starts climbing rapidly.
>
> So I guess the question is whether this rate of exit is representative
> enough of real life to warrant making any more changes to the existing
> patchset, beyond the locking changes in 2. above.
>
> >From my limited experience, I think this is too high an exit rate
> to be worrying about overhead.
>

1000/sec isn't terribly high. CGI servers, shell scripts.

And kernel development ;) A `pushpatch 1500' here does 992 fork/exec/exit
per second.

> %ovhd of tgid on over off
> (higher is worse)
>
> Exit User Sys Elapsed
> Rate Time Time Time
>
> 2283 25.76 649.41 -0.14
> 1193 -10.53 88.81 -0.12
> 963 -11.90 3.28 -0.10
> 806 -8.54 -0.84 0.16
> 694 -4.41 2.38 0.03

Oh wow. Something's gone quadratic there.