Messages in this thread | | | Date | Mon, 31 Dec 2001 20:47:43 +0100 (CET) | From | Dave Jones <> | Subject | Re: [patch] Prefetching file_read_actor() |
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On Mon, 31 Dec 2001, Andrew Morton wrote:
> Looks like you'll need to do a __get_user() against the page to > populate the tlb. We're going to need it in the copy_to_user() > anyway, so the cost is negligible.
Completly puzzled right now. Moving the prefetching to copy_to_user (and doing the tlb preload & prefetching the whole chunk to be copied (or cachesize if smaller)) results in a performance drop instead of a win.
My initial guess is that some of the callers of copy_to_user are doing something that is harmed the prefetching. (Maybe they are doing additional prefetch() calls)
Dave
-- | Dave Jones. http://www.codemonkey.org.uk | SuSE Labs
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