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On Sun, 30 Jan 2000, Steve Underwood wrote: > Davide Libenzi wrote: > > > On Sat, 29 Jan 2000, Horst von Brand wrote: > > > In case your application switches rapidly, it is thrashing the cache, which > > > is crucial for performance with current CPUs. You simply don't want to do > > > that, ever. You get best performance by _never_ switching unless forced to > > > do so, but that isn't realistic. > > > > If You switch fast You have more cache reloads of probably less cache lines ( > > or pages ). > > Since a task that run a short time has a lower probability to "touch" RAM > > locations. > > On what type of application mix to you base that hypothesis? > > Programs which reschedule at a high rate seem usually to be those shunting large > blocks of data around, without doing an awful lot of processing on them. They > can touch a great deal of data in a very short time. One way to test that hypothesis: disable the level 2 cache. Normally you would expect a 10-20 times slowdown. If the slowdown is significantly less, then the application is making non-optimal use of the cache. john alvord - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.rutgers.edu Please read the FAQ at http://www.tux.org/lkml/ | ||||||||||||
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