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| author | Sajan Karumanchi <sajan.karumanchi@amd.com> | 2020-10-28 13:05:33 +0530 |
|---|---|---|
| committer | Florian Weimer <fweimer@redhat.com> | 2020-10-28 09:57:14 +0100 |
| commit | 59803e81f96b479c17f583b31eac44b57591a1bf (patch) | |
| tree | a580e2fd555e4d83fb095b2f2523cb180e5df4c1 | |
| parent | 641a12484562b3a740b940620ac2c47a626c9861 (diff) | |
| download | glibc-59803e81f96b479c17f583b31eac44b57591a1bf.zip glibc-59803e81f96b479c17f583b31eac44b57591a1bf.tar.gz glibc-59803e81f96b479c17f583b31eac44b57591a1bf.tar.bz2 | |
x86: Optimizing memcpy for AMD Zen architecture.
Modifying the shareable cache '__x86_shared_cache_size', which is a
factor in computing the non-temporal threshold parameter
'__x86_shared_non_temporal_threshold' to optimize memcpy for AMD Zen
architectures.
In the existing implementation, the shareable cache is computed as 'L3
per thread, L2 per core'. Recomputing this shareable cache as 'L3 per
CCX(Core-Complex)' has brought in performance gains.
As per the large bench variant results, this patch also addresses the
regression problem on AMD Zen architectures.
Reviewed-by: Premachandra Mallappa <premachandra.mallappa@amd.com>
| -rw-r--r-- | sysdeps/x86/cacheinfo.h | 32 |
1 files changed, 26 insertions, 6 deletions
diff --git a/sysdeps/x86/cacheinfo.h b/sysdeps/x86/cacheinfo.h index 7f342fd..1296c93 100644 --- a/sysdeps/x86/cacheinfo.h +++ b/sysdeps/x86/cacheinfo.h @@ -320,7 +320,7 @@ init_cacheinfo (void) threads = 1 << ((ecx >> 12) & 0x0f); } - if (threads == 0) + if (threads == 0 || cpu_features->basic.family >= 0x17) { /* If APIC ID width is not available, use logical processor count. */ @@ -335,13 +335,30 @@ init_cacheinfo (void) if (threads > 0) shared /= threads; - /* Account for exclusive L2 and L3 caches. */ - shared += core; - } + /* Get shared cache per ccx for Zen architectures. */ + if (cpu_features->basic.family >= 0x17) + { + unsigned int eax; + + /* Get number of threads share the L3 cache in CCX. */ + __cpuid_count (0x8000001D, 0x3, eax, ebx, ecx, edx); + + unsigned int threads_per_ccx = ((eax >> 14) & 0xfff) + 1; + shared *= threads_per_ccx; + } + else + { + /* Account for exclusive L2 and L3 caches. */ + shared += core; + } + } } if (cpu_features->data_cache_size != 0) - data = cpu_features->data_cache_size; + { + if (data == 0 || cpu_features->basic.kind != arch_kind_amd) + data = cpu_features->data_cache_size; + } if (data > 0) { @@ -354,7 +371,10 @@ init_cacheinfo (void) } if (cpu_features->shared_cache_size != 0) - shared = cpu_features->shared_cache_size; + { + if (shared == 0 || cpu_features->basic.kind != arch_kind_amd) + shared = cpu_features->shared_cache_size; + } if (shared > 0) { |