From: Steinar H. Gunderson <sesse@debian.org>
Date: Sun, 11 Jan 2009 18:33:32 +0000 (+0100)
Subject: Measure CPU seconds instead of wall time, and move the timing functions into a
X-Git-Url: https://git.sesse.net/?p=fjl;a=commitdiff_plain;h=4b87e80c1ee4dd6a5d5c13e7b4321a956f53378f

Measure CPU seconds instead of wall time, and move the timing functions into a
separate module.
---

diff --git a/Makefile b/Makefile
index 926fa57..c3e6ff7 100644
--- a/Makefile
+++ b/Makefile
@@ -1,10 +1,10 @@
 CC=gcc
 CFLAGS=-std=gnu99 -O2 -msse4.1 -g -Wall -Wextra
-LDFLAGS=-lm
+LDFLAGS=-lm -lrt
 
 all: tests
 
-UNSTUFF_TEST_OBJS=unstuff.o unstuff_test.o
+UNSTUFF_TEST_OBJS=unstuff.o unstuff_test.o benchmark.o
 unstuff_test: $(UNSTUFF_TEST_OBJS)
 	$(CC) $(LDFLAGS) -o $@ $(UNSTUFF_TEST_OBJS)
 
@@ -20,7 +20,7 @@ BYTESOURCE_TEST_OBJS=bytesource.o choice.o unstuff.o bytesource_test.o
 bytesource_test: $(BYTESOURCE_TEST_OBJS)
 	$(CC) $(LDFLAGS) -o $@ $(BYTESOURCE_TEST_OBJS)
 
-IDCT_TEST_OBJS=idct.o idct_test.o
+IDCT_TEST_OBJS=idct.o idct_test.o benchmark.o
 idct_test: $(IDCT_TEST_OBJS)
 	$(CC) $(LDFLAGS) -o $@ $(IDCT_TEST_OBJS)
 
diff --git a/idct_test.c b/idct_test.c
index e35a17b..cf2556b 100644
--- a/idct_test.c
+++ b/idct_test.c
@@ -3,9 +3,8 @@
 #include <stdlib.h>
 #include <math.h>
 #include <assert.h>
-#include <time.h>
-#include <sys/time.h>
 
+#include "benchmark.h"
 #include "idct.h"
 
 // Generate random coefficients in the range [-15..15].
@@ -99,17 +98,14 @@ void test_performance(idct_func_t* idct)
 		quant[i] = 1;
 	}
 
-	struct timeval start, now;
-	gettimeofday(&start, NULL);
+	start_benchmark_timer();
 
 	for (unsigned i = 0; i < num_runs; ++i) {
 		(*idct)(coeff, quant, output);
 	}
 	
-	gettimeofday(&now, NULL);
-
-	double diff = timediff(&start, &now);
-	printf("%u runs in %.2f seconds = %.2f IDCTs/sec\n",
+	double diff = stop_benchmark_timer();
+	printf("%u runs in %.2f CPU seconds = %.2f IDCTs/sec\n",
 		num_runs, diff, num_runs / diff);
 }
 
diff --git a/unstuff_test.c b/unstuff_test.c
index 863aef5..a5bf92d 100644
--- a/unstuff_test.c
+++ b/unstuff_test.c
@@ -1,9 +1,8 @@
 #include <stdio.h>
 #include <string.h>
 #include <assert.h>
-#include <time.h>
-#include <sys/time.h>
 
+#include "benchmark.h"
 #include "unstuff.h"
 
 void test_basic_unstuff(unstuff_func_t* unstuff)
@@ -67,12 +66,6 @@ void gen_random_stuffed_data(uint8_t* dst, size_t len)
 	}
 }
 
-double timediff(const struct timeval* a, const struct timeval* b)
-{
-	return (double)(b->tv_sec - a->tv_sec) +
-		(double)(b->tv_usec - a->tv_usec) * 1e-6;
-}
-
 void test_performance(unstuff_func_t* unstuff)
 {
 	const size_t len = 4096;
@@ -81,19 +74,16 @@ void test_performance(unstuff_func_t* unstuff)
 	uint8_t src[len], dst[len];
 	gen_random_stuffed_data(src, len);
 
-	struct timeval start, now;
-	gettimeofday(&start, NULL);
+	start_benchmark_timer();
 
 	for (unsigned i = 0; i < num_runs; ++i) {
 		int ret = unstuff(dst, src, len);
 		assert(ret != -1);
 	}
 	
-	gettimeofday(&now, NULL);
-
-	double diff = timediff(&start, &now);
+	double diff = stop_benchmark_timer();
 	double mb_sec = (len * num_runs) / (1048576.0 * diff);
-	printf("%u runs with %zu bytes in %.2f seconds = %.2f MB/sec\n",
+	printf("%u runs with %zu bytes in %.2f CPU seconds = %.2f MB/sec\n",
 		num_runs, len, diff, mb_sec);
 }