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74 lines
2 KiB
C
74 lines
2 KiB
C
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/*
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* =====================================================================================
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*
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* Filename: rdtsc.c
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*
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* Description:
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*
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* Version: 1.0
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* Created: 24.01.2011 13:41:30
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* Revision: none
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* Compiler: gcc
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*
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* Author: Georg Wassen (gw) (),
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* Company:
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*
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* =====================================================================================
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*/
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#ifndef RDTSC_H
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#define RDTSC_H
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#include <stdint.h>
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/*
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* rdtsc_ticks_per_sec(): measure frequency. Takes below a second.
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*/
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uint64_t rdtsc_ticks_per_sec(void) __attribute__((optimize(3)));
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typedef union __attribute__((__transparent_union__))
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{
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uint64_t *__u64;
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struct {uint32_t __low; uint32_t __high;} *__u32;
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} tsc_t;
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/*
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* rdtsc(): Register-save version (compiler may insert additional push/pop)
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* (clobbered-registers not given b/c compiler deduces from output-registers)
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*/
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static inline void __attribute__((__always_inline__, gnu_inline, optimize(3))) rdtsc(tsc_t tsc)
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{
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__asm__ volatile ("rdtsc" : "=a"(tsc.__u32->__low), "=d"(tsc.__u32->__high) );
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}
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/*
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* rdtsc_serial(): get RDTSC with leading and rear serializing LFENCE instruction
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*/
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static inline void __attribute__((__always_inline__, gnu_inline, optimize(3))) rdtsc_serialized(tsc_t tsc)
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{
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#if ! __MIC__
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__asm__ volatile (
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"lfence\n\t" // serialize (needs SSE2, available since AMD Athlon64, Intel Core)
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"rdtsc\n\t"
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"lfence\n\t"
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: "=a"(tsc.__u32->__low), "=d"(tsc.__u32->__high) );
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#else
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__asm__ volatile (
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"lock; add $0, 0(%%rsp)\n\t" // serialize
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"rdtsc\n\t"
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"lock; add $0, 0(%%rsp)\n\t" // serialize
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: "=a"(tsc.__u32->__low), "=d"(tsc.__u32->__high) :: "memory" );
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#endif
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}
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void rdtsc_loop(uint64_t ticks);
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void rdtsc_loop_sec(unsigned seconds);
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uint64_t rdtsc_max_freq(int id);
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int rdtsc_is_invariant(void);
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uint64_t rdtsc_get_overhead(uint64_t iterations);
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uint64_t rdtsc_get_overhead_serialized(uint64_t iterations);
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#endif
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