c818a18146
RDTSC serialization using cpuid is not needed for Intel platforms. This increases gettimeofday performance. Cc: vojtech@suse.cz Cc: rohit.seth@intel.com Signed-off-by: Andi Kleen <ak@suse.de> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
49 lines
1.1 KiB
C
49 lines
1.1 KiB
C
/*
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* linux/include/asm-x86_64/timex.h
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*
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* x86-64 architecture timex specifications
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*/
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#ifndef _ASMx8664_TIMEX_H
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#define _ASMx8664_TIMEX_H
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#include <asm/8253pit.h>
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#include <asm/msr.h>
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#include <asm/vsyscall.h>
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#include <asm/hpet.h>
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#include <asm/system.h>
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#include <asm/processor.h>
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#include <linux/compiler.h>
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#define CLOCK_TICK_RATE PIT_TICK_RATE /* Underlying HZ */
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typedef unsigned long long cycles_t;
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static inline cycles_t get_cycles (void)
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{
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unsigned long long ret;
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rdtscll(ret);
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return ret;
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}
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/* Like get_cycles, but make sure the CPU is synchronized. */
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static __always_inline cycles_t get_cycles_sync(void)
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{
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unsigned long long ret;
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unsigned eax;
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/* Don't do an additional sync on CPUs where we know
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RDTSC is already synchronous. */
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alternative_io(ASM_NOP2, "cpuid", X86_FEATURE_SYNC_RDTSC,
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"=a" (eax), "0" (1) : "ebx","ecx","edx","memory");
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rdtscll(ret);
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return ret;
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}
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extern unsigned int cpu_khz;
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extern int read_current_timer(unsigned long *timer_value);
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#define ARCH_HAS_READ_CURRENT_TIMER 1
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extern struct vxtime_data vxtime;
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#endif
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