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| author | Noah Goldstein <goldstein.w.n@gmail.com> | 2022-06-15 10:41:29 -0700 |
|---|---|---|
| committer | Noah Goldstein <goldstein.w.n@gmail.com> | 2022-06-15 14:25:55 -0700 |
| commit | b446822b6ae4e8149902a78cdd4a886634ad6321 (patch) | |
| tree | 417d3ee01f93bd92db817203660b6f8591f625f8 /manual | |
| parent | 686216945a7873237bf892bbe38a2eef23aadeba (diff) | |
| download | glibc-b446822b6ae4e8149902a78cdd4a886634ad6321.zip glibc-b446822b6ae4e8149902a78cdd4a886634ad6321.tar.gz glibc-b446822b6ae4e8149902a78cdd4a886634ad6321.tar.bz2 | |
x86: Add bounds `x86_non_temporal_threshold`
The lower-bound (16448) and upper-bound (SIZE_MAX / 16) are assumed
by memmove-vec-unaligned-erms.
The lower-bound is needed because memmove-vec-unaligned-erms unrolls
the loop aggressively in the L(large_memset_4x) case.
The upper-bound is needed because memmove-vec-unaligned-erms
right-shifts the value of `x86_non_temporal_threshold` by
LOG_4X_MEMCPY_THRESH (4) which without a bound may overflow.
The lack of lower-bound can be a correctness issue. The lack of
upper-bound cannot.
Diffstat (limited to 'manual')
| -rw-r--r-- | manual/tunables.texi | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/manual/tunables.texi b/manual/tunables.texi index 1482412..2c07601 100644 --- a/manual/tunables.texi +++ b/manual/tunables.texi @@ -47,7 +47,7 @@ glibc.malloc.mxfast: 0x0 (min: 0x0, max: 0xffffffffffffffff) glibc.elision.skip_lock_busy: 3 (min: -2147483648, max: 2147483647) glibc.malloc.top_pad: 0x0 (min: 0x0, max: 0xffffffffffffffff) glibc.cpu.x86_rep_stosb_threshold: 0x800 (min: 0x1, max: 0xffffffffffffffff) -glibc.cpu.x86_non_temporal_threshold: 0xc0000 (min: 0x0, max: 0xffffffffffffffff) +glibc.cpu.x86_non_temporal_threshold: 0xc0000 (min: 0x4040, max: 0x0fffffffffffffff) glibc.cpu.x86_shstk: glibc.cpu.hwcap_mask: 0x6 (min: 0x0, max: 0xffffffffffffffff) glibc.malloc.mmap_max: 0 (min: -2147483648, max: 2147483647) |