Joerg Roedel wrote:
From: Joerg Roedel <[EMAIL PROTECTED]>
This patch simplifies the get_cycles_sync() function by removing
the #ifdefs from it. Further it introduces an optimization for AMD
processors. There the RDTSCP instruction is used instead of CPUID;RDTSC
which is helpfull if the kernel runs as a KVM guest. Running as a guest
makes CPUID very expensive because it causes an intercept of the guest.
+#define RDTSCP ".byte 0x0f, 0x01, 0xf9"
+ alternative_io_two("cpuid\nrdtsc",
+ "rdtsc", X86_FEATURE_SYNC_RDTSC,
+ ".byte 0x0f, 0x01, 0xf9", X86_FEATURE_RDTSCP,
why not use the RDTSCP macro here?
--
Do not meddle in the internals of kernels, for they are subtle and quick to
panic.
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