Date: Thu, 27 Mar 2003 03:16:02 -0800 From: Eivind Eklund <eivind@FreeBSD.org> To: Tor Egge <tegge@FreeBSD.org> Cc: cvs-all@FreeBSD.org Subject: Re: cvs commit: src/sys/conf NOTES files options src/sys/kern vfs_bio.c src/sys/ufs/ffs ffs_rawread.c ffs_vnops.c Message-ID: <20030327031602.C77894@FreeBSD.org> In-Reply-To: <200303262340.h2QNegJg065498@repoman.freebsd.org>; from tegge@FreeBSD.org on Wed, Mar 26, 2003 at 03:40:42PM -0800 References: <200303262340.h2QNegJg065498@repoman.freebsd.org>
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On Wed, Mar 26, 2003 at 03:40:42PM -0800, Tor Egge wrote: > tegge 2003/03/26 15:40:42 PST > > FreeBSD src repository > > Modified files: > sys/conf NOTES files options > sys/kern vfs_bio.c > sys/ufs/ffs ffs_vnops.c > Added files: > sys/ufs/ffs ffs_rawread.c > Log: > Add support for reading directly from file to userland buffer when the > O_DIRECT descriptor status flag is set and both offset and length is a > multiple of the physical media sector size. Why only in the O_DIRECT case? O_DIRECT is normally used to avoid caching effects *in order to avoid side effects of caching*, at the cost of speed. This patch seems to do the opposite - speed up the codepath significantly. Not that it isn't nice - it would just be even nicer to have available some way to just say "max speed, please". Eivind.
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