Messages in this thread | | | From | Bartlomiej Zolnierkiewicz <> | Subject | Re: [PATCH] speed up SATA | Date | Sun, 28 Mar 2004 20:30:11 +0200 |
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On Sunday 28 of March 2004 20:12, William Lee Irwin III wrote: > On Sun, Mar 28, 2004 at 07:54:36PM +0200, Jens Axboe wrote: > > Sorry, but I cannot disagree more. You think an artificial limit at the > > block layer is better than one imposed at the driver end, which actually > > has a lot more of an understanding of what hardware it is driving? This > > makes zero sense to me. Take floppy.c for instance, I really don't want > > 1MB requests there, since that would take a minute to complete. And I > > might not want 1MB requests on my Super-ZXY storage, because that beast > > completes io easily at an iorate of 200MB/sec. > > So you want to put this _policy_ in the block layer, instead of in the > > driver. That's an even worse decision if your reasoning is policy. The > > only such limits I would want to put in, are those of the bio where > > simply is best to keep that small and contained within a single page to > > avoid higher order allocations to do io. Limits based on general sound > > principles, not something that caters to some particular piece of > > hardware. I absolutely refuse to put a global block layer 'optimal io > > size' restriction in, since that is the ugliest of policies and without > > having _any_ knowledge of what the hardware can do. > > How about per-device policies and driver hints wrt. optimal io?
Yep, user-tunable per-device policies with sane driver defaults.
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