[coreboot] Patch merged into coreboot/master: b60dd4e Synchronize rdtsc instructions

gerrit at coreboot.org gerrit at coreboot.org
Thu Aug 9 00:38:40 CEST 2012

the following patch was just integrated into master:
commit b60dd4eb5bca71cb70c51b4933b04516fb372258
Author: Stefan Reinauer <reinauer at chromium.org>
Date:   Tue Aug 7 14:44:51 2012 -0700

    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 at google.com>

Build-Tested: build bot (Jenkins) at Wed Aug  8 23:26:00 2012, giving +1
See http://review.coreboot.org/1422 for details.


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