lkml.org 
[lkml]   [2001]   [May]   [4]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [patch] 2.4.4 alpha semaphores optimization
On Thu, May 03, 2001 at 07:28:48PM +0200, Andrea Arcangeli wrote:
> I'd love if you could port it on top of this one and to fix it so that
> it can handle up to 2^32 sleepers and not only 2^16 like we have to do
> on the 32bit archs to get good performance:
>
> ftp://ftp.us.kernel.org/pub/linux/kernel/people/andrea/kernels/v2.4/2.4.4aa3/00_rwsem-11

It could be done without much pain for both "official" and your rwsem
implementations.
However, there are 3 reasons why I prefer 16-bit counters:
a. "max user processes" ulimit is much lower than 64K anyway;
b. "long" count would cost extra 8 bytes in the struct rw_semaphore;
c. I can use existing atomic routines which deal with ints.

Actually I'm more anxious about a __builtin_expect() problem,
and I'd like to hear Richard's comment on this...

Ivan.
-
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 12:52    [from the cache]
©2003-2011 Jasper Spaans. Advertise on this site