lkml.org 
[lkml]   [2005]   [Jul]   [3]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH 3/3] Use conditional
On Sun, Jul 03, 2005 at 05:44:05PM +0200, Kurt Garloff wrote:

Agree with James, pls resend to linux-security-module@wirex.com.

The topic of replacing dummy (with capability) was discussed there
last week, in the context of stacker, but a common solution for both
cases would be needed.

Also, I was going to ask where 4/5 and 5/5 were :-)

If you are claiming a perf increase it would be nice to get an idea
what these patches were even though you believe most of the gain was
in patch #3.

Thanks

> Hi,
>
> this optimizes the case where no LSM is loaded and the (new) default
> capablities is used. These are not called via indirect calls but
> called as hardcoded calls and might thus be inlined; the price for
> this is a conditional -- benchmarks done by hp showed this to be
> beneficial (on ia64).
>
> Enjoy,
> --
> Kurt Garloff, Director SUSE Labs, Novell Inc.

> From: Kurt Garloff <garloff@suse.de>
> Subject: Replace indirect calls by a branch
> References: SUSE40217, SUSE39439
>
> In the LSM stub collection, rather do a branch than an indirect
> call. Many of the functions called do only return 0 or do nothing
> for the default (capability) case.
> This is a fast-path optimization; a branch is faster than an
> indirect call, even more so if correctly predicted.
> This shows a >3% perf. increase in netperf -t TCP_RR benchmark on IA64.
> (More exactly: The benchmark was taken with the next two patches
> applied as well, but I attribute the main effect to this patch.)
>
> This is patch 3/5 of the LSM overhaul.
-
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: 2005-07-03 21:07    [W:0.213 / U:0.028 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site