Messages in this thread | | | Date | Tue, 25 Jul 2006 06:59:21 +0200 | From | Arjan van de Ven <> | Subject | Re: CFQ will be the new default IO scheduler - why? |
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Al Boldi wrote: > Arjan van de Ven wrote: >>>> Should there be a default scheduler per filesystem? As some >>>> filesystems may perform better/worse with one over another? >>> It's currently perDevice, and should probably be extended to perMount. >> Hi, > > Hi! > >> per mount is going to be "not funny". I assume the situation you are >> aiming for is the "3 partitions on a disk, each wants its own elevator". >> The way the kernel currently works is that IO requests the filesystem >> does are first flattened into an IO for the entire device (eg the >> partition mapping is done) and THEN the IO scheduler gets involved to >> schedule the IO on a per disk basis. > > IC. That probably explains why concurrent io-procs have such a hard time > getting through to the disk. They probably just hang in the flatting phase, > waiting for something to take care of their requests. > flattening is just an addition in the cpu, that's just really boring and shouldn't be visible anywhere performance wise - 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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