Messages in this thread | | | Date | Mon, 12 Mar 2007 18:08:11 +0200 | From | Avi Kivity <> | Subject | Re: [PATCH 4/4 TRY#3] optimize and simplify get_cycles_sync() |
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Joerg Roedel wrote: > On Fri, Mar 09, 2007 at 08:10:03PM +0200, Avi Kivity wrote: > >> Joerg Roedel wrote: >> >>> From: Joerg Roedel <joerg.roedel@amd.com> >>> >>> 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? >> > > Does this macro exist? I couldn't found it in the current git tree. And > the rdtscp macros in msr.h use the plain opcode too. >
-ENOCOFFEE? You defined the macro 3 lines above the .byte directive...
-- error compiling committee.c: too many arguments to function
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