Re: Raw i/o usage wrecks block device performance??

Hi, On Wed, Oct 11, 2000 at 09:28:57PM +0100, Chris Evans wrote: > > The problem is best described with a little sequence. After using raw i/o > facilities, streamed block device reads from the same underlying device > exhibit much poorer performance than before the raw i/o. > > Anyone know wha

Raw i/o usage wrecks block device performance??

Hi, Here's a very strange (and repeatable) result. Affects 2.2.x + raw device patches (i.e. RH7.0). Also had a similar effect on 2.4.0test9! The problem is best described with a little sequence. After using raw i/o facilities, streamed block device reads from the same underlying device exhibit