cvs commit: src/sys/conf NOTES files options src/sys/kern
vfs_bio.c src/sys/ufs/ffs ffs_rawread.c ffs_vnops.c
eivind at FreeBSD.org
Thu Mar 27 03:16:05 PST 2003
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
> 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".
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