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[Emacs-diffs] master 81a1088: Tweak builtin symbol order for speed
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From: |
Paul Eggert |
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Subject: |
[Emacs-diffs] master 81a1088: Tweak builtin symbol order for speed |
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Date: |
Sat, 13 Jul 2019 17:54:06 -0700 |
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User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.7.2 |
On 7/12/19 12:12 AM, Pip Cet wrote:
I don't understand why this would improve performance this
significantly (maybe because it allows 8-bit offsets to be used rather
than 32-bit ones?).
Yes, that's my guess too. For the record, my benchmark platform was my old work
desktop (AMD Phenom II X4 910e, circa 2010) running Fedora 30 x86-64, with plain
'make compile-always' (no -j). I really should get that upgraded.
Maybe it would be a good idea to make Vdead a symbol (or a tagged NULL
pointer) and treat it similarly, if this actually improves
performance.
It does speed up GC a bit. I installed the attached. Thanks for the suggestion.
+ static char const commonsym[][8]
I'm curious, why isn't this simply "static char *commonsym[]"?
Old performance habits that don't matter here. Besides, that alternative should
be 'static char const *const commonsym[]" which is not obviously simpler....
0001-Replace-Vdead-with-tagged-pointer.patch
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