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Re: Comparison of GCC-4.9 and LLVM-3.4 performance on SPECInt2000 for x86-64 and ARM
- From: Vladimir Makarov <vmakarov at redhat dot com>
- To: Ramana Radhakrishnan <ramana dot radhakrishnan at arm dot com>, "gcc.gcc.gnu.org" <gcc at gcc dot gnu dot org>
- Date: Wed, 25 Jun 2014 10:01:46 -0400
- Subject: Re: Comparison of GCC-4.9 and LLVM-3.4 performance on SPECInt2000 for x86-64 and ARM
- Authentication-results: sourceware.org; auth=none
- References: <53A98705 dot 10909 at redhat dot com> <53A98CE2 dot 9080108 at arm dot com> <53A98F0A dot 7000802 at redhat dot com> <53A991D7 dot 6070709 at arm dot com>
On 2014-06-24, 10:57 AM, Ramana Radhakrishnan wrote:
The ball-park number you have probably won't change much.
I don't think Neon can improve score for SPECInt2000 significantly but
may be I am wrong.
It won't probably improve the overall score by a large amount but some
individual benchmarks will get some help.
Did you add any other architecture specific options to your SPEC2k
No. The only options I used are -Ofast.
Could you recommend me what best options you think I should use for this
I would personally use --with-cpu=cortex-a15 --with-fpu=neon-vfpv4
--with-float=hard on this processor as that maps with the processor
available on that particular piece of Silicon.
I've tried this options too. As I guessed it resulted in GCC
improvement of eon only by 6% which improved overall score by less 0.5%.
No change for LLVM though. Eon is more fp benchmark with my point of
view and it should be in SPECFP but it is a different story.
I've tried GCC SPECFP2000 also with and without this options and it gave
about 12% improvement (1006 vs 988). That is a *huge* improvement. I
guess using NEON for ARM is really important for fp benchmarks.