From: eric@tantalus.nrl.navy.mil (Eric Youngdale) Subject: Re: SCSI Performance (Yet Again) Date: Thu, 26 Aug 1993 16:16:27 GMT
In article <1993Aug25.181139.17869@swan.pyr> iiitac@swan.pyr (Alan Cox) writes:
>
>Before people go berserk with wild optimizations the Linux driver doesn't
>handle two optimizations it could (at least if it does then Linus has
>cleverly concealed it 8-))
>
>2. Request merging - Multiple requests can be merged into one
> disk operation. This should enable better use to be made of the
> DMA potentially.
Request merging does take place for requests that are contiguous
(i.e. requests to read adjacent sectors on the disk). These merged requests
are used in the scsi code by drivers that use DMA by making use of a feature
called scatter-gather.
-Eric
-- "When Gregor Samsa woke up one morning from unsettling dreams, he found himself changed in his bed into a lawyer."