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| author | H.J. Lu <hjl.tools@gmail.com> | 2017-06-02 17:32:21 -0700 |
|---|---|---|
| committer | H.J. Lu <hjl.tools@gmail.com> | 2017-06-02 17:32:37 -0700 |
| commit | 808fd9e6fe23f96078d4e297de1131117d3898bb (patch) | |
| tree | 76336f1f7937cfd45db787e7b659a77da655ba26 /sysdeps | |
| parent | 3e6def237a5681387b27ac55298b3ab25a054dbf (diff) | |
| download | glibc-808fd9e6fe23f96078d4e297de1131117d3898bb.zip glibc-808fd9e6fe23f96078d4e297de1131117d3898bb.tar.gz glibc-808fd9e6fe23f96078d4e297de1131117d3898bb.tar.bz2 | |
x86: Update __x86_shared_non_temporal_threshold
__x86_shared_non_temporal_threshold was set to 6 times of per-core
shared cache size, based on the large memcpy micro benchmark in glibc
on a 8-core processor. For a processor with more than 8 cores, the
threshold is too low. Set __x86_shared_non_temporal_threshold to the
3/4 of the total shared cache size so that it is unchanged on 8-core
processors. On processors with less than 8 cores, the threshold is
lower.
* sysdeps/x86/cacheinfo.c (__x86_shared_non_temporal_threshold):
Set to the 3/4 of the total shared cache size.
Diffstat (limited to 'sysdeps')
| -rw-r--r-- | sysdeps/x86/cacheinfo.c | 6 |
1 files changed, 4 insertions, 2 deletions
diff --git a/sysdeps/x86/cacheinfo.c b/sysdeps/x86/cacheinfo.c index 12ffeef..f66f2b8 100644 --- a/sysdeps/x86/cacheinfo.c +++ b/sysdeps/x86/cacheinfo.c @@ -767,8 +767,10 @@ intel_bug_no_cache_info: /* The large memcpy micro benchmark in glibc shows that 6 times of shared cache size is the approximate value above which non-temporal - store becomes faster. */ - __x86_shared_non_temporal_threshold = __x86_shared_cache_size * 6; + store becomes faster on a 8-core processor. This is the 3/4 of the + total shared cache size. */ + __x86_shared_non_temporal_threshold + = __x86_shared_cache_size * threads * 3 / 4; } #endif |