lkml.org 
[lkml]   [1999]   [Jul]   [31]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [patch] 'multimedia latency patch', lowlatency-2.2.10-M6


On Sat, 31 Jul 1999, Ingo Molnar wrote:
> On Sat, 31 Jul 1999, Benno Senoner wrote:
>
> > as Roger Larrson suspected, there are some parts in the kernel
> > which have a too long execution path:
> > On his PPro with 512MB RAM, d_lookup takes up to 80ms to execute !
>
> yes. I've attached a patch that is supposed to make things much better.

No. Check the numbers first, d_lookup() doesn't do anything heavy (it just
follows a linked list of entries - even assuming a lot of cache misses
that would probably imply more dentries than you can fit in 512MB).

Basically, if d_lookup() takes 80ms, there's a bug somewhere. Don't try to
paper it over by adding "reschedule" calls.

The bug may be a completely buggered hash function or similar.

Or the bug may be the latency measurement.

In either case, trying to add band-aid over it is the wrong solution.

Linus


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

\
 
 \ /
  Last update: 2005-03-22 13:53    [W:1.188 / U:0.048 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site