Re: SCHED_ULE on desktop system

From: Jeff Roberson <jroberson_at_chesapeake.net>
Date: Mon, 1 Oct 2007 11:30:16 -0700 (PDT)
On Mon, 1 Oct 2007, Marc Fonvieille wrote:

> On Tue, Sep 18, 2007 at 12:44:52AM -0700, Jeff Roberson wrote:
>>
>> Marcus,
>>
>> What has happened is that you have run an x application that is so
>> expensive we no longer consider it interactive.  Unfortunately, due to the
>> nature of the x server architecture, much of the compute time is spent in
>> x11 rather than the offending application.  There really isn't anything to
>> be done in this case other than mark X as real-time.  You can try to tune
>> up the interactivity heuristic limit by setting kern.sched.interact to a
>> higher value.  This will help with short term bursts of x server cpu
>> utilization, however, sustained, expensive x windows processing will always
>> trigger poorer interactive behavior.
>>
>
> I have the same problems as Roman: once I compile something, most of X
> applications become slow as hell with lagging screen refresh.  That's on
> -CURRENT (with all debug, malloc, invariant things disabled) with ULE
> and Xorg 4.3 (I'll test with the legacy scheduler as soon as possible).
> This behavior does not occur on 6.2 but with Xorg 7.2, so I really suspect
> last Xorg release to be guilty.  Jeff you often mentioned tests on your
> laptop, could you check what Xorg version your run?

xorg-7.2            X.Org complete distribution metaport
xorg-server-1.2.0_2,1 X.Org X server and related programs

If you're running very recent current you can try renicing X negatively. 
If you nice -20 and it doesn't improve then it's probably not the cpu 
scheduler causing the delay.  What display driver are you using?  How much 
cpu is X using while you're experiencing the lag?

Thanks,
Jeff

>
> I played with kern.sched.interact MIB but it was worse.
>
> -- 
> Marc
>
Received on Mon Oct 01 2007 - 16:27:42 UTC

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