lkml.org 
[lkml]   [2003]   [Aug]   [7]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH][2.6-mm] Readahead issues and AIO read speedup
Badari Pulavarty <pbadari@us.ibm.com> wrote:
>
> We should do readahead of actual pages required by the current
> read would be correct solution. (like Suparna suggested).

I repeat: what will be the effect of this if all those pages are already in
pagecache?

> When readahead window is closed, slow read code will be submitting IO in 4k
> chunks. Infact, it will wait for the IO to finish, before reading next page.
> Isn't it?

Yes.

> How would you ensure atleast 16k worth of pages are submitted
> in a sinle chunk here ?

Need to work out why the window got itself shrunk, fix that, then constrain each
readahead chunk to the size of the application's read() if the application
just seeked, I think.

> I am hoping that forcing readhead code to read pages needed by current read
> would address this problem.

You'll have Martin and Anton coming after you with SDET regressions.


-
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 13:47    [W:0.071 / U:0.076 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site