cvs commit: src/sys/conf NOTES files options src/sys/kern
vfs_bio.c src/sys/ufs/ffs ffs_rawread.c ffs_vnops.c
bright at mu.org
Thu Mar 27 09:39:24 PST 2003
* Eivind Eklund <eivind at 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 at 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.'
More information about the cvs-src