Messages in this thread | | | Date | Wed, 19 Apr 2006 10:37:24 +0200 | From | Andreas Mohr <> | Subject | Re: [ck] Re: [patch][rfc] quell interactive feeding frenzy |
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Hi,
On Mon, Apr 17, 2006 at 10:08:08AM +1000, Con Kolivas wrote: > On Monday 17 April 2006 04:44, Andreas Mohr wrote: > > Hi, > > > > On Sun, Apr 16, 2006 at 09:22:59AM +1000, Con Kolivas wrote: > > > The current value, 6ms at 1000HZ, is chosen because it's the largest > > > value that can schedule a task in less than normal human perceptible > > > range when two competing heavily cpu bound tasks are the same priority. > > > At 250HZ it works out to 7.5ms and 10ms at 100HZ. Ironically in my > > > experimenting I found the cpu cache improvements become much less > > > significant above 7ms so I'm very happy with this compromise. > > > > Heh, this part is *EXACTLY* a fully sufficient explanation of what I was > > wondering about myself just these days ;) > > (I'm experimenting with different timeslice values on my P3/450 to verify > > what performance impact exactly it has) > > However with a measly 256kB cache it probably doesn't matter too much, > > I think. > > > > But I think it's still important to mention that your perception might be > > twisted by your P4 limitation (no testing with slower and really slow > > machines). > > You underestimate me. Those cpu cache effects were performance effects > measured down to a PII 233, but all were i386 architecture. As for > "perception" this isn't my testing I'm talking about; these are > neuropsychiatric tests that have nothing to do with pcs or what processor you > use ;)
OK, but I was not worrying about the interactivity aspects, rather the performance aspects (GUI updates of KDE 3.5.2 on P3/450/256MB on Ubuntu are about as slow as medium-hot lava). While of course it's mostly KDE (and probably also the S3 Savage driver/card) which is to blame here, I'm trying to first do as much as possible at kernel level before eventually going higher up the chain...
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