Messages in this thread | | | Date | Sat, 8 Dec 2001 02:54:46 +0100 | From | Jens Axboe <> | Subject | Re: highmem question |
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On Fri, Dec 07 2001, Marvin Justice wrote: > > There is no way of fixing it. > > All I know is that a streaming io app I was playing with showed a drastic > performance hit when the kernel was compiled with CONFIG_HIGHMEM. On W2K we > saw no slowdown with 2 or even 4GB of RAM so I think solutions must exist.
That's because of highmem page bouncing when doing I/O. There is indeed a solution for this -- 2.5 or 2.4 + block-highmem-all patches will happily do I/O directly to any page in your system as long as your hardware supports it. I'm sure we're beating w2k with that enabled :-)
-- Jens Axboe
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