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okay, I'm tired of my temporary hacking (yes, it's just temporary; only even "nice" values are allowed) and I've just returned to the original 2.6.11.10 kernel and read your message :) I understand it is the "destiny" of HT. Thanks! On 5/19/05, Con Kolivas <kernel@kolivas.org> wrote: > On Thu, 19 May 2005 08:46 pm, Tetsuji "Maverick" Rai wrote: > > I've done a temporary minor hacking, which tells kernel only the half > > value of nice in all processes. Actually idle percentage was lowered, > > but the response of the main application became slower (as a matter of > > course.) > > > > I'm not sure which is better..if possible I want to take advantages of > > each one :) Am I expecting too much? > > Yes you are. Hyperthreading (currently depending on workload) only gives you > on average 15-25% more cpu with multiple threads. You can't get something for > nothing. Either the nice 0 task runs slower because a low priority task is > bound to the sibling, or it runs at the same speed and the low priority task > runs for less. If you want the nice 19 task to use more cpu run it at nice 0 > - because this is effectively what you are trying to do. If you want more cpu > you need extra true physical cpus, not logical cores. > > Your code does not do what you think it is doing either. If you want to change > the bias between nice levels across logical cores search the code for where > the value of sd->per_cpu_gain is set. It is currently set to 25% and you want > to increase it (although as I said you will derive no real world benefit as > your nice 0 task will just slow down). > > Cheers, > Con > -- Luckiest in the world / Weapon of Mass Distraction http://maverick6664.bravehost.com/ Aviation Jokes: http://www.geocities.com/tetsuji_rai/ Background: http://maverick.ns1.name/ - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ | ||||||||||||
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