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/*
Copyright 2005-2017 Free Software Foundation, Inc.
Contributed by Patrick Pelissier, INRIA.
This file is part of the MPFR Library.
The MPFR Library is free software; you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 3 of the License, or (at your
option) any later version.
The MPFR Library is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
License for more details.
You should have received a copy of the GNU Lesser General Public License
along with the MPFR Library; see the file COPYING.LESSER. If not, see
http://www.gnu.org/licenses/ or write to the Free Software Foundation, Inc.,
51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA. */
#ifndef __TIMP__H__
#define __TIMP__H__
/* Usage:
* Before doing the measure, call TIMP_OVERHEAD ();
* Then unsigned long long t = TIMP_MEASURE (f(x));
* to measure the # of cycles taken by the call to f(x).
*/
#define TIMP_VERSION 1*100+1*10+0
#ifndef __GNUC__
# error CC != GCC
#endif
/* High accuracy timing */
#if defined (USE_CLOCK_MONOTONIC)
/* Needs to include -lrt in the library section */
#include <time.h>
#define timp_rdtsc() \
({unsigned long long int x; \
struct timespec ts; \
clock_gettime(CLOCK_MONOTONIC, &ts); \
x = ts.tv_sec * 1000000000UL + ts.tv_nsec; \
x; })
#define timp_rdtsc_before(time) (time = timp_rdtsc())
#define timp_rdtsc_after(time) (time = timp_rdtsc())
#elif defined (__i386__) || defined(__amd64__)
#if !defined(corei7) && !defined(__core_avx2__)
/* The following implements Section 3.2.3 of the article cited below. */
#define timp_rdtsc_before(time) \
__asm__ __volatile__( \
".p2align 6\n\t" \
"xorl %%eax,%%eax\n\t" \
"cpuid\n\t" \
"rdtsc\n\t" \
"movl %%eax,(%0)\n\t" \
"movl %%edx,4(%0)\n\t" \
"xorl %%eax,%%eax\n\t" \
"cpuid\n\t" \
: /* no output */ \
: "S"(&time) \
: "eax", "ebx", "ecx", "edx", "memory")
#define timp_rdtsc_after(time) \
__asm__ __volatile__( \
"xorl %%eax,%%eax\n\t" \
"cpuid\n\t" \
"rdtsc\n\t" \
"movl %%eax,(%0)\n\t" \
"movl %%edx,4(%0)\n\t" \
"xorl %%eax,%%eax\n\t" \
"cpuid\n\t" \
: /* no output */ \
: "S"(&time) \
: "eax", "ebx", "ecx", "edx", "memory")
#else
/* corei7 and corei5 offer newer instruction rdtscp, which should be better,
see https://www.intel.com/content/dam/www/public/us/en/documents/white-papers/ia-32-ia-64-benchmark-code-execution-paper.pdf */
#define timp_rdtsc_before(time) \
__asm__ __volatile__( \
".p2align 6\n\t" \
"xorl %%eax,%%eax\n\t" \
"cpuid\n\t" \
"rdtsc\n\t" \
"movl %%eax,(%0)\n\t" \
"movl %%edx,4(%0)\n\t" \
: /* no output */ \
: "S"(&time) \
: "eax", "ebx", "ecx", "edx", "memory")
#define timp_rdtsc_after(time) \
__asm__ __volatile__( \
"rdtscp\n\t" \
"movl %%eax,(%0)\n\t" \
"movl %%edx,4(%0)\n\t" \
"xorl %%eax,%%eax\n\t" \
"cpuid\n\t" \
: /* no output */ \
: "S"(&time) \
: "eax", "ebx", "ecx", "edx", "memory")
#endif
#elif defined (__ia64)
#define timp_rdtsc() \
({ unsigned long long int x; \
__asm__ __volatile__("mov %0=ar.itc" : "=r"(x) :: "memory"); \
x; })
#define timp_rdtsc_before(time) (time = timp_rdtsc())
#define timp_rdtsc_after(time) (time = timp_rdtsc())
#elif defined (__alpha)
#define timp_rdtsc() \
({ unsigned long long int x; \
__asm__ volatile ("rpcc %0\n\t" : "=r" (x)); \
x; })
#define timp_rdtsc_before(time) (time = timp_rdtsc())
#define timp_rdtsc_after(time) (time = timp_rdtsc())
#else
# error Unsupported CPU
#endif
/* We do several measures and keep the minimum to avoid counting
* hardware interrupt cycles.
* The filling of the CPU cache is done because we do several loops,
* and get the minimum.
* Declaring num_cycle as "volatile" is to avoid optimization when it is
* possible (to properly compute overhead).
* overhead is calculated outside by a call to:
* overhead = MEASURE("overhead", ;)
* Use a lot the preprocessor.
* It is a macro to be very flexible.
*/
static unsigned long long int timp_overhead = 0;
#define TIMP_NUM_TRY 4327
#define TIMP_MAX_WAIT_FOR_MEASURE 10000000ULL
#define TIMP_MEASURE_AUX(CODE) \
({ \
volatile unsigned long long int num_cycle, num_cycle2; \
unsigned long long int min_num_cycle, start_num_cycle; \
int _i; \
timp_rdtsc_before (start_num_cycle); \
min_num_cycle = 0xFFFFFFFFFFFFFFFFLL; \
for(_i = 0 ; _i < TIMP_NUM_TRY ; _i++) { \
timp_rdtsc_before(num_cycle); \
CODE; \
timp_rdtsc_after(num_cycle2); \
num_cycle = num_cycle2 < num_cycle ? 0 /* shouldn't happen */ \
: num_cycle2 - num_cycle; \
if (num_cycle < min_num_cycle) \
min_num_cycle = num_cycle; \
if (num_cycle2 - start_num_cycle > TIMP_MAX_WAIT_FOR_MEASURE) \
break; \
} \
min_num_cycle < timp_overhead ? 0 : min_num_cycle - timp_overhead; })
/* If the return value of TIMP_MEASURE_AUX() is 0, this probably means
that timp_overhead was too large and incorrect; this can occur just
after starting the process. In this case, TIMP_OVERHEAD() is called
again to recompute timp_overhead and the timing is redone. */
#define TIMP_MEASURE(CODE) \
({ \
unsigned long long int _m; \
while ((_m = TIMP_MEASURE_AUX(CODE)) == 0) \
TIMP_OVERHEAD(); \
_m; })
#define TIMP_OVERHEAD() \
(timp_overhead = 0, timp_overhead = TIMP_MEASURE_AUX((void) 0) )
#endif /* __TIMP__H__ */
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