Messages in this thread | | | Date | Thu, 8 Jun 2006 13:00:45 +0200 | From | Jens Axboe <> | Subject | Re: [PATCH] updated reiser4 - reduced cpu usage for writes by writing more than 4k at a time (has implications for generic write code and eventually for the IO layer) |
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On Wed, May 24 2006, Hans Reiser wrote: > Tom Vier wrote: > > >On Tue, May 23, 2006 at 01:14:54PM -0700, Hans Reiser wrote: > > > > > >>underlying FS can be improved. Performance results show that the new > >>code consumes 40% less CPU when doing "dd bs=1MB ....." (your hardware, > >>and whether the data is in cache, may vary this result). Note that this > >>has only a small effect on elapsed time for most hardware. > >> > >> > > > >Write requests in linux are restricted to one page? > > > > > > > It may go to the kernel as a 64MB write, but VFS sends it to the FS as > 64MB/4k separate 4k writes.
Nonsense, there are ways to get > PAGE_CACHE_SIZE writes in one chunk. Other file systems have been doing it for years.
-- Jens Axboe
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