From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <001601c28a92$e4a0d8c0$0200a8c0@telia.com> From: "Joakim Tjernlund" To: "Tom Rini" Cc: "LinuxPPC" , References: <20021112162504.GI658@opus.bloom.county> <20021112184025.GA9033@opus.bloom.county> Subject: Re: ppc_8xx-gcc 2.95.3 Monta Vista does not do ANY loop unrolling Date: Tue, 12 Nov 2002 22:30:12 +0100 MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Sender: owner-linuxppc-embedded@lists.linuxppc.org List-Id: > On Tue, Nov 12, 2002 at 05:46:49PM +0100, Joakim Tjernlund wrote: > > > > > Now to the trick question(s): > > > > Where might it be suitable to add -funroll-loops or, better yet, can it be done > > > > with a pragma or attribute attached to the function in question? It's pretty > > > > hard to unroll inline functions otherwise (and only the inline function). > > > > > > Well, to lib/Makefile: > > > ifeq ($(CONFIG_PPC32),y) > > > CFLAGS_crc32.o += -funroll-loops > > > endif > > > > > > Should work. And it's not unheard of. > > > > Yes, that much I already figured, but are there OTHER places in > > the kernel that also might benefit from unrolling. I don't know the > > kernel as well as you do and was hoping for a lead or two. > > Not really. Unfortunatly what might be better is to figure out how it > works on i386, and then figure out how to duplicate that logic on PPC, > maybe making it another flag and then turned on for different sizes > based on -mtune. well, according to Mark Hatle it's only gcc 3.3-pre that does this kind of unrolling automatically so that will take a very long time before it's figured out and usable. So maybe it's worth the effort to figure out a few hot spots and apply -funroll-loops there. -mtune is new to me, need to look that one up. > > > > > Any progress on the i2c-algo-8xx.c and/or 8xx_io/enet.c patches I sent earlier? > > > > > > As I said privatly, Dan Malek is handling the enet patch, and I'm > > > looking for time to do the i2c one. Right now I'm working on making the > > > kernel easier to tweak (in some ways) for 2.5. > > > > I know Dan is handling the enet stuff, but since you both work > > for MV(don't you?) I figured you might know, being an insider and all :-) > > I don't follow you. Dan doesn't work for MVista now. Sorry, I didn't know that. > > > Maybe your tweak stuff could make use of forced unrolling? > > Eventually, it could be used for turning it on or off for the whole > kernel, or for a specific area even, once I get Makefile tweaks working. > First I'm trying to get dependancies right. makes sense. Jocke ** Sent via the linuxppc-embedded mail list. See http://lists.linuxppc.org/