Re: [PATCH] add likely around access_ok for uaccess
From: Pavel Machek
Date: Tue Sep 16 2003 - 16:00:48 EST
> > > while trying to figure out why sysv msg is around 30% slower than pipes
> > > for data transfers I noticed that gcc's autodetection (3.2.2) guesses
> > > the "if(access_ok())" tests in uaccess.h wrong and puts the error memset
> > > into the direct path and the copy out of line.
> > >
> > > The attached patch adds likely to the tests - any objections? What about
> > > the archs except i386?
> > How much speedup did you gain?
> How much can it hurt?
The change is obviously okay, I just wanted to know... If it gains 30%
on sysv messages.. that would be pretty big surprise.
When do you have a heart between your knees?
[Johanka's followup: and *two* hearts?]
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/