| commit | 4abd9b1396a17ff654c642feaf02af4e0f3b60e4 | |
| author | Mark Williams <mwilliams@fb.com> | |
| Fri, 2 Mar 2018 13:58:25 +0000 (2 05:58 -0800) | ||
| committer | Hhvm Bot <hhvm-bot@users.noreply.github.com> | |
| Fri, 2 Mar 2018 14:11:24 +0000 (2 06:11 -0800) | ||
| tree | 396fef8cebda6a7a957b08929cbac4682240ff27 | treesnapshot (tar.gz zip) |
| parent | d7a5dc86ebb735e5c184578d1df6e9af5fcad9a6 | commitdiff |
Use hash_int64 in the Fixup TreadHashMap
Summary:
We originally argued that since x64 instruction lengths are arbitrary,
the identity hash would be fine. And thats probably true(ish) for
x64. For PPC and Arm, instructions are all 4 bytes, so when the table
is 75% full, the average chain length will be 3.
Use hash_int64 instead (which is implemented by the hardware crc32
instruction when available). This will probably be an improvement on
x64, and will definitely be an improvement on Arm and PPC.
Reviewed By: ricklavoie
Differential Revision: D7115026
fbshipit-source-id: 2d3b3641386076f7af0dbf9a1ef0d7d2e7bf8e3b
Summary:
We originally argued that since x64 instruction lengths are arbitrary,
the identity hash would be fine. And thats probably true(ish) for
x64. For PPC and Arm, instructions are all 4 bytes, so when the table
is 75% full, the average chain length will be 3.
Use hash_int64 instead (which is implemented by the hardware crc32
instruction when available). This will probably be an improvement on
x64, and will definitely be an improvement on Arm and PPC.
Reviewed By: ricklavoie
Differential Revision: D7115026
fbshipit-source-id: 2d3b3641386076f7af0dbf9a1ef0d7d2e7bf8e3b
| hphp/runtime/vm/jit/fixup.cpp | diffblobblamehistory |