Date: Wed, 15 Feb 2012 17:06:52 +0200 From: "Pavlo" <devgs@ukr.net> To: freebsd-fs@freebsd.org Subject: ZFS and mem management Message-ID: <70229.1329318412.9319724204137054208@ffe16.ukr.net>
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>On 15/02/2012 13:39, Pavlo wrote: >> >> >> >> Unfortunately we can't afford disabling prefetch. It is too much of an>> overhead.>> >> Also I made some tests. I have process that maps file using mmap() and>> writes or reads first byte of each page of mapped file with some data.> >Note that ZFS is designed so that it interacts somewhat badly with >mmap() and other kernel services which rely on coherency between VM and >IO such as sendfile(). At the very best, you will have two in-kernel >copies of all data buffers used with such interfaces, but there have >been sporadic reports that there are other bugs with it. > >If you have a test server, I'd recommend you do the same test on UFS for >comparison. Was going to try this... Thanks for reply.
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