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