lkml.org 
[lkml]   [2002]   [May]   [11]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: O_DIRECT performance impact on 2.4.18 (was: Re: [PATCH] 2.5.14 IDE 56)
On Sat, May 11 2002, Roy Sigurd Karlsbakk wrote:
> On Friday 10 May 2002 17:55, Linus Torvalds wrote:
> > On Fri, 10 May 2002, Lincoln Dale wrote:
> > > so O_DIRECT in 2.4.18 still shows up as a 55% performance hit versus no
> > > O_DIRECT. anyone have any clues?
> >
> > Yes.
> >
> > O_DIRECT isn't doing any read-ahead.
> >
> > For O_DIRECT to be a win, you need to make it asynchronous.
>
> Will the use of O_DIRECT affect disk elevatoring?

No, the I/O scheduler can't even tell whether it's being handed
O_DIRECT buffers or not.

Jens
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2005-03-22 13:26    [from the cache]
©2003-2011 Jasper Spaans