Messages in this thread | | | Date | Wed, 28 Feb 2007 15:05:01 +0100 | From | "Joerg Roedel" <> | Subject | [PATCH 0/4] improve alternative instruction code and optimize get_cycles_sync |
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This series of patches extend the alternative instructions framework on i386 and x86_64 architectures to support two alternative instruction replacements. This code is used together with the introduction of the X86_FEATURE_SYNC_RDTSC flag on i386 to simplify and optimize the get_cycles_sync() function. The optimization changes this function to use RDTSCP instead of CPUID;RDTSC if this instruction is available. Don't use CPUID there is really important if the kernel runs as a KVM guest, because this instruction is intercepted and causes an expensive VMEXIT.
-- Joerg Roedel Operating System Research Center AMD Saxony LLC & Co. KG
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