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Re: Performance question concerning chicken flonum vs "foreign flonum"
From: |
felix . winkelmann |
Subject: |
Re: Performance question concerning chicken flonum vs "foreign flonum" |
Date: |
Sat, 06 Nov 2021 17:50:46 +0100 |
> a patch would be great, if it is not too much work. Attached you find three
> assembly language files:
>
> * fma-test_original.s (unchananged csc c to assembly)
> * fma-test_modified.s (modified csc c from previous mail)
> * fma-test_modified_mfma.s (modified csc c and -mfma gcc option)
>
> all files were created with the additional gcc arguments -O3 -S
> -fverbose-asm. Are these files sufficient?
Yes, thanks a lot. the third case shows that the intrinsic is indeed used.
>
> I hoped the fma libc function would insulate one from intrinsics; the
> compiler option -mfma should activate (I think via defining a C macro) the
> use of the corresponding CPU instruction (fma3 on current x86), which my CPU
> supports, but using it does not seem to make a difference.
Suprising, but I guess, the speedup is too minor, in the presence of all the
noise regarding stack
usage, etc. In straight-line, dumb, cache-friendly C code it may make a
difference, I guess...
I will provide an experimental patch for the new operation. Stay tuned.
felix
- Performance question concerning chicken flonum vs "foreign flonum", christian.himpe, 2021/11/04
- Re: Performance question concerning chicken flonum vs "foreign flonum", Jörg F. Wittenberger, 2021/11/04
- Re: Performance question concerning chicken flonum vs "foreign flonum", felix . winkelmann, 2021/11/04
- Re: Performance question concerning chicken flonum vs "foreign flonum", Christian Himpe, 2021/11/05
- Re: Performance question concerning chicken flonum vs "foreign flonum", felix . winkelmann, 2021/11/05
- Re: Performance question concerning chicken flonum vs "foreign flonum", Christian Himpe, 2021/11/06
- Re: Performance question concerning chicken flonum vs "foreign flonum",
felix . winkelmann <=
- Re: Performance question concerning chicken flonum vs "foreign flonum", felix . winkelmann, 2021/11/07
- Re: Performance question concerning chicken flonum vs "foreign flonum", Christian Himpe, 2021/11/07
- Re: Performance question concerning chicken flonum vs "foreign flonum", felix . winkelmann, 2021/11/07
- Re: Performance question concerning chicken flonum vs "foreign flonum", Christian Himpe, 2021/11/07