On Mon, 2008-02-25 at 13:22 +0100, Peter Zijlstra wrote:
> Subject: sched: revert load_balance_monitor()
>
> The following commit causes a number of serious regressions:
>
> commit 6b2d7700266b9402e12824e11e0099ae6a4a6a79
> Author: Srivatsa Vaddagiri <[EMAIL PROTECTED]>
> Date: Fri Jan 25 21:08:00 2008 +0100
> sched: group scheduler, fix fairness of cpu bandwidth allocation for task
> groups
>
> Namely:
> - very frequent wakeups on SMP, reported by PowerTop users.
> - cacheline trashing on (large) SMP
> - some latencies larger than 500ms
>
> While there is a mergeable patch to fix the latter, the former issues
> are IMHO not fixable in a manner suitable for .25 (we're at -rc3 now).
> Hence I propose to revert this patch and try again for .26.
>
> ( minimal revert - leaves most of the code present, just removes the
> activation
> and sysctl interface ).
top - 14:05:56 up 3 min, 16 users, load average: 4.31, 2.14, 0.85
Tasks: 218 total, 5 running, 213 sleeping, 0 stopped, 0 zombie
Cpu(s): 35.5%us, 64.5%sy, 0.0%ni, 0.0%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ P COMMAND
5294 mikeg 20 0 1464 364 304 R 99 0.0 1:00.08 0 chew-max
5278 root 20 0 1464 364 304 R 32 0.0 0:27.86 1 chew-max
5279 root 20 0 1464 360 304 R 32 0.0 0:35.53 1 chew-max
5290 root 20 0 1464 364 304 R 31 0.0 0:29.00 1 chew-max
The minimal revert seems to leave group fairness in a worse state than
what the original patch meant to fix. Maybe a full revert would be
better?
-Mike
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