Messages in this thread | | | Date | Sat, 3 Jan 2004 14:40:03 -0800 | From | Andrew Morton <> | Subject | Re: Strange IDE performance change in 2.6.1-rc1 (again) |
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Paolo Ornati <ornati@lycos.it> wrote: > > I know these are only performance in sequential data reads... and real life > is another thing... but I think the author of the patch should be informed > (Ram Pai).
There does seem to be something whacky going on with readahead against blockdevices. Perhaps it is related to the soft blocksize. I've never been able to reproduce any of this.
Be aware that buffered reads for blockdevs are treated fairly differently from buffered reads for regular files: they only use lowmem and we always attach buffer_heads and perform I/O against them.
No effort was made to optimise buffered blockdev reads because it is not very important and my main interest was in data coherency and filesystem metadata consistency.
If you observe the same things reading from regular files then that is more important.
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