[<prev] [next>] [<thread-prev] [day] [month] [year] [list]
Message-ID: <20070524224147.GF4470@stusta.de>
Date: Fri, 25 May 2007 00:41:47 +0200
From: Adrian Bunk <bunk@...sta.de>
To: Roland Dreier <rdreier@...co.com>
Cc: Rob Landley <rob@...dley.net>,
Arjan van de Ven <arjan@...ux.intel.com>,
linux-kernel@...r.kernel.org
Subject: Re: Status of CONFIG_FORCED_INLINING?
On Thu, May 24, 2007 at 11:32:07AM -0700, Roland Dreier wrote:
> > The problem is that inline functions in headers are intended to be
> > called from different C files.
> >
> > gcc might not inline it in the C files where it is called more than
> > once.
> >
> > But it will always inline it if it's called only once.
> >
> > One of both will be suboptimal, but from gcc's perspective it was
> > optimal.
>
> Yes, we could probably get huge benefits from --combine and/or
> -fwhole-program to let gcc see more than one file at a time.
>
> But I still don't see the issue with having gcc do the best it can on
> each file it compiles. If you force the inlining, then that means
> that on files where not inlining was better, you've forced gcc to
> generate worse code. (I don't see how not inlining could be locally
> better on a single file but globally worse, even though it generated
> better code on each compiled file)
Can you give examples where for one function it differs between
different C files whether it should be inlined or not?
cu
Adrian
--
"Is there not promise of rain?" Ling Tan asked suddenly out
of the darkness. There had been need of rain for many days.
"Only a promise," Lao Er said.
Pearl S. Buck - Dragon Seed
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
Powered by blists - more mailing lists