Messages in this thread | | | Subject | Re: [tip:x86/asm] x86/defconfig: Turn on CONFIG_CC_OPTIMIZE_FOR_SIZE= y in the 64-bit defconfig | From | "H. Peter Anvin" <> | Date | Sat, 26 Jan 2013 07:18:26 -0800 |
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On the CPUs Ling is testing on the downsides of -Os probably matter less, in particular since rep movsb works well.
It is questionable as a generic default, though.
The whole -Ok discussion came from that.
Borislav Petkov <bp@alien8.de> wrote:
>On Sat, Jan 26, 2013 at 04:25:57AM -0800, tip-bot for Ma Ling wrote: >> During the same time (269.410275674 seconds) IPC from Os is >> 0.37, O2 is 0.36, Os improved performance 2.7%. >> >> Signed-off-by: Ma Ling <ling.ml@alipay.com> >> Cc: Linus Torvalds <torvalds@linux-foundation.org> >> Cc: Arjan van de Ven <arjan@linux.intel.com> >> Cc: Andrew Morton <akpm@linux-foundation.org> >> Cc: Jan Beulich <jbeulich@suse.com> >> Cc: Steven Rostedt <rostedt@goodmis.org> >> Link: >http://lkml.kernel.org/r/1359123061-6139-1-git-send-email-ling.ma@alipay.com >> [ So, this is a bit symbolic as most people don't use the defconfig, >> but the measurements are useful nevertheless so let's commit this >> if there are no objections. ] > >What about > >commit 3a55fb0d9fe8e2f4594329edd58c5fd6f35a99dd >Author: Kirill Smelkov <kirr@mns.spb.ru> >Date: Fri Nov 2 15:41:01 2012 +0400 > > Tell the world we gave up on pushing CC_OPTIMIZE_FOR_SIZE > >? > >Reportedly, -Os generates suboptimal code in certain cases and we >advise >against it with this patch.
-- Sent from my mobile phone. Please excuse brevity and lack of formatting.
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