Date: Tue, 18 Sep 2007 00:44:52 -0700 (PDT) From: Jeff Roberson <jroberson@chesapeake.net> To: Marcus Reid <marcus@blazingdot.com> Cc: freebsd-current@freebsd.org, Roman Bogorodskiy <novel@freebsd.org> Subject: Re: SCHED_ULE on desktop system Message-ID: <20070918004027.G558@10.0.0.1> In-Reply-To: <20070918061806.GA85425@blazingdot.com> References: <20070916061932.GA93480@underworld.novel.ru> <20070918061806.GA85425@blazingdot.com>
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On Mon, 17 Sep 2007, Marcus Reid wrote: > On Sun, Sep 16, 2007 at 10:19:32AM +0400, Roman Bogorodskiy wrote: >> Hello, >> >> I'm curious if SCHED_ULE is designed to be used on a desktop system. I'm >> running -CURRENT at home and tried to use SCHED_ULE for some time. It >> works alright while the load is not very high. But once I start >> compiling something (running 'make buildworld' or 'portupgrade -a' for >> example), the machine comes almost unusable - X11's windows takes a lot >> of time to redraw, changing virtual desktop in window manager may take >> a several seconds. And it's nearly impossible to watch some movie with >> mplayer. > > I find SCHED_ULE to provide much better interactivity than SCHED_BSD on > my desktop. Normally, I can have a couple of compiles and a bunch of > other stuff going on in the background and I can't even feel it, and > I'm on a UP p4. I can, however, reproduce what you're talking about. > It's always something graphically intensive that gets it going, and it > only happens when there's a couple of compiles running in the background. > I tried to trigger it for hours doing a ton of stuff non-graphical, > including running a couple of jobs that made it go a gig into swap. > It handled everything nicely. However, every time I do something like > start an opengl app and drag it around or start xlock, with compiles > in the background, things get very stuttery. After closing the offending > app, it continues to be like that for a while, and eventually corrects > itself and goes back to normal. > 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. Thanks, Jeff > I suspected xorg was maybe blocking on some writes to something but > looking at the kdump of xorg didn't reveal anything to me. > >> However, when I switch to SCHED_4BSD, system's reaction time gets lower >> and I even can watch a movie with mplayer when compiling something. > > I haven't tried SCHED_4BSD yet. I'll have more time tomorrow. > > Marcus > _______________________________________________ > freebsd-current@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-current > To unsubscribe, send any mail to "freebsd-current-unsubscribe@freebsd.org" >
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