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From a45cebf11522b3112fba3d682224a232ae5e2e98 Mon Sep 17 00:00:00 2001
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From: Andreas Arnez <arnez@linux.ibm.com>
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Date: Wed, 12 Dec 2018 19:44:32 +0100
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Subject: [PATCH 4/8] Read L1 data cache size from sysconf if possible
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The probing of the L1 data cache size is sometimes not reliable. This can
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cause the tuning to yield varying, sub-obtimal results. But on Linux the
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L1 data cache size can usually be retrieved with sysconf instead, which is
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faster and more reliable. Do this whenever possible.
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---
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tune/sysinfo/L1CacheSize.c | 12 +++++++++++-
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1 file changed, 11 insertions(+), 1 deletion(-)
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diff --git a/tune/sysinfo/L1CacheSize.c b/tune/sysinfo/L1CacheSize.c
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index e62a273..dffa76e 100644
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--- a/tune/sysinfo/L1CacheSize.c
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+++ b/tune/sysinfo/L1CacheSize.c
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@@ -30,6 +30,7 @@
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#include <stdio.h>
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#include <stdlib.h>
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+#include <unistd.h>
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#define REPS 4096
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@@ -276,7 +277,16 @@ int main(int nargs, char *args[])
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exit(-1);
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}
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if (nargs > 1) MaxSize = atoi(args[1]);
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- L1Size = GetL1Size(MaxSize, 1.08);
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+
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+#ifdef _SC_LEVEL1_DCACHE_SIZE
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+ {
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+ long res = sysconf(_SC_LEVEL1_DCACHE_SIZE);
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+ L1Size = res > 0 ? (int) (res / 1024) : 0;
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+ }
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+#endif
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+
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+ if (!L1Size)
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+ L1Size = GetL1Size(MaxSize, 1.08);
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if (!L1Size)
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L1Size = GetL1Size(MaxSize, 1.08);
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if (!L1Size)
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--
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2.23.0
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