Date: Thu, 27 Mar 2003 09:39:18 -0800 From: Alfred Perlstein <bright@mu.org> To: Eivind Eklund <eivind@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: <20030327173918.GZ48996@elvis.mu.org> In-Reply-To: <20030327031602.C77894@FreeBSD.org> References: <200303262340.h2QNegJg065498@repoman.freebsd.org> <20030327031602.C77894@FreeBSD.org>
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* Eivind Eklund <eivind@FreeBSD.org> [030327 03:16] wrote: > 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". Actually this is what O_DIRECT was intended to be as soon as someone got around to it. I initially thought it would be dillon, but tegge was a pleasant suprise. :) -- -Alfred Perlstein [alfred@freebsd.org] 'Instead of asking why a piece of software is using "1970s technology," start asking why software is ignoring 30 years of accumulated wisdom.'
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