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| author | Stefan Reinauer <reinauer@chromium.org> | 2012-08-07 14:44:51 -0700 |
|---|---|---|
| committer | Stefan Reinauer <stefan.reinauer@coreboot.org> | 2012-08-09 00:38:39 +0200 |
| commit | 0db6820b10c3452764ab62173c3b75cefbf6c215 (patch) | |
| tree | 95abc6378ed60c37e14de842a7baf014dc60111b /src/cpu/intel/model_1067x | |
| parent | 4c29d7f27d315ab93c811fb86ba246151dc84da3 (diff) | |
Synchronize rdtsc instructions
The CPU can arbitrarily reorder calls to rdtsc, significantly
reducing the precision of timing using the CPUs time stamp counter.
Unfortunately the method of synchronizing rdtsc is different
on AMD and Intel CPUs. There is a generic method, using the cpuid
instruction, but that uses up a lot of registers, and is very slow.
Hence, use the correct lfence/mfence instructions (for CPUs that
we know support it)
Change-Id: I17ecb48d283f38f23148c13159aceda704c64ea5
Signed-off-by: Stefan Reinauer <reinauer@google.com>
Reviewed-on: http://review.coreboot.org/1422
Reviewed-by: Alexandru Gagniuc <mr.nuke.me@gmail.com>
Tested-by: build bot (Jenkins)
Diffstat (limited to 'src/cpu/intel/model_1067x')
| -rw-r--r-- | src/cpu/intel/model_1067x/Kconfig | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/src/cpu/intel/model_1067x/Kconfig b/src/cpu/intel/model_1067x/Kconfig index b079922275..852c9cdf0c 100644 --- a/src/cpu/intel/model_1067x/Kconfig +++ b/src/cpu/intel/model_1067x/Kconfig @@ -2,3 +2,4 @@ config CPU_INTEL_MODEL_1067X bool select SMP select SSE2 + select TSC_SYNC_MFENCE |