Re: Performance of function calls of SH?(Fw: [RFC][selinux] Tuning SELinux permission check

[Yuichi N. <yn...@hi...>]

On Mon, 10 Sep 2007 16:09:10 +0900
Paul Mundt wrote:
> On Mon, Sep 10, 2007 at 03:58:21PM +0900, Yuichi Nakamura wrote:
> > On Mon, 10 Sep 2007 14:56:25 +0900
> > Paul Mundt wrote:
> > > On Mon, Sep 10, 2007 at 02:37:04PM +0900, Yuichi Nakamura wrote:
> > > > I would like to try newer gcc.
> > > > 
> > > 
> > > http://userweb.kernel.org/~lethal/gnush4_linux_v0702_rc-1-1.i386.tar.gz
> > Thanks, It is useful!
> > I used gcc in above and compiled kernel.
> > 
> > I found that performance does not get better when compiled by 4.2.1.
> > Even 3.4.5 is better???
> > 
> What optimization levels are you using to compile the kernel? Try with
> and without -Os to see if there's a measurable impact. From the sounds of
> it you're still going to have to do the manual inlining work if there's
> no change in the common case, at least.
I was using -O2.
I now compiled with -Os and compared.

lmbench result for SH(SH4, SH7751R), kernel 2.6.22
               SELinux(gcc4.2.1 -O2)  SELinux(gcc 4.2.1 -Os)
Simple read     6.03                  4.24
Simple write    5.92                  3.88
Very strange. -Os is better.
# I tried twice to make sure.

               No SELinux(gcc4.2.1 -O2)  No SELinux(gcc 4.2.1 -Os)
Simple read    2.36                       2.45
Simple write   2.06                       2.08
Without SELinux, O2 is a little better.

Regards,
-- 
Yuichi Nakamura
Hitachi Software Engineering Co., Ltd.
Japan SELinux Users Group(JSELUG): http://www.selinux.gr.jp/
SELinux Policy Editor: http://seedit.sourceforge.net/