From 95cec6a5ecfdc2a75ba041a6e9f9cd568d53a6fc Mon Sep 17 00:00:00 2001
From: Mattias Andrée <maandree@kth.se>
Date: Wed, 27 Apr 2016 21:39:19 +0200
Subject: More accurate benchmarking
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Signed-off-by: Mattias Andrée <maandree@kth.se>
---
 bench/benchmark.h | 134 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 134 insertions(+)
 create mode 100644 bench/benchmark.h

(limited to 'bench/benchmark.h')

diff --git a/bench/benchmark.h b/bench/benchmark.h
new file mode 100644
index 0000000..6d6aa87
--- /dev/null
+++ b/bench/benchmark.h
@@ -0,0 +1,134 @@
+#if defined(__linux__)
+# define _GNU_SOURCE
+# include <sched.h>
+#endif
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <time.h>
+#include <unistd.h>
+
+
+#ifdef BENCHMARK_LIB
+# include BENCHMARK_LIB
+#else
+# include "../zahl.h"
+# define BIGINT_LIBRARY "libzahl"
+#endif
+
+
+#ifndef CLOCK_MONOTONIC_RAW
+# define CLOCK_MONOTONIC_RAW CLOCK_MONOTONIC
+#endif
+
+
+#ifdef __x86_64__
+# define RDTSC_MAYBE_SUPPORTED
+#endif
+
+
+#if !defined(USE_RDTSC) && !defined(USE_CLOCK) && !defined(USE_GETTIME)
+# if 1 && defined(RDTSC_MAYBE_SUPPORTED) && defined(__linux__)
+#  define USE_RDTSC
+# elif 1
+#  define USE_CLOCK
+# else
+#  define USE_GETTIME
+# endif
+#endif
+
+
+static struct timespec dur;
+static char timebuf[512];
+#if defined(USE_RDTSC)
+typedef unsigned long long int rdtsc_t;
+static unsigned int start_high, start_low, end_high, end_low;
+static unsigned long long int freq;
+#elif defined(USE_CLOCK)
+static clock_t start, end;
+#else
+static struct timespec start;
+#endif
+
+
+static void
+benchmark_init(void)
+{
+#if defined(__linux__)
+	cpu_set_t cpuset;
+# if defined(USE_RDTSC)
+	FILE *f;
+	char *line = 0;
+	size_t size = 0;
+# endif
+	CPU_ZERO(&cpuset);
+	CPU_SET(0, &cpuset);
+	sched_setaffinity(getpid(), sizeof(cpuset), &cpuset);
+# if defined(USE_RDTSC)
+	f = fopen("/sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_max_freq", "r");
+	if (getline(&line, &size, f) < 0)
+		abort();
+	fclose(f);
+	freq = strtoull(line, 0, 10);
+	free(line);
+# endif
+#endif
+	(void) timebuf;
+}
+
+
+#if defined(USE_RDTSC) && defined(__x86_64__)
+static inline void
+rdtsc(unsigned int *low, unsigned int *high)
+{
+	__asm__ __volatile__ ("rdtsc" : "=a"(*low), "=d"(*high));
+}
+static inline rdtsc_t
+rdtsc_join(unsigned int low, unsigned int high)
+{
+	return (rdtsc_t)low | (((rdtsc_t)high) << 32);
+}
+#endif
+
+
+#if defined(USE_RDTSC)
+# define TIC  (rdtsc(&start_low, &start_high))
+# define TOC\
+	do {\
+		rdtsc_t dur_cycles;\
+		double dur_seconds;\
+		rdtsc(&end_low, &end_high);\
+		dur_cycles = rdtsc_join(end_low, end_high);\
+		dur_cycles -= rdtsc_join(start_low, start_high);\
+		dur_seconds = dur_cycles;\
+		dur_seconds /= freq;\
+		dur_seconds /= 1000;\
+		dur_seconds -= dur.tv_sec = (int)dur_seconds;\
+		dur.tv_nsec = dur_seconds * 1000000000L;\
+	} while (0)
+#elif defined(USE_CLOCK)
+# define TIC  (start = clock())
+# define TOC\
+	do {\
+		end = clock();\
+		dur.tv_sec = (end - start) / 1000000ULL;\
+		dur.tv_nsec = ((end - start) % 1000000ULL) * 1000;\
+	} while (0)
+#elif defined(USE_GETTIME)
+# define TIC  clock_gettime(CLOCK_MONOTONIC_RAW, &start)
+# define TOC\
+	do {\
+		clock_gettime(CLOCK_MONOTONIC_RAW, &dur);\
+		dur.tv_sec -= start.tv_sec;\
+		dur.tv_nsec -= start.tv_nsec;\
+		if (dur.tv_nsec < 0) {\
+			dur.tv_nsec += 1000000000L;\
+			dur.tv_sec -= 1;\
+		}\
+	} while (0)
+#endif
+
+
+#define TICKS  (dur.tv_sec * 1000000000ULL + dur.tv_nsec)
+#define STIME  (sprintf(timebuf, "%lli.%09li", (long long)(dur.tv_sec), dur.tv_nsec), timebuf)
-- 
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