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nodejs/benchmark/io.c
Ben Noordhuis 78ca555845 bench: optimize io.c benchmark
Use static buffers. Most clock ticks were spent in malloc() and free() instead
of read() and write().

Fix measurements. Really fast runs would result in bogus results like:

  Wrote 1048576000 bytes in -0.731630s using 8192 byte buffers: -1366.811093mB/s
2011-11-10 21:13:37 +01:00

122 lines
2.1 KiB
C

/**
* gcc -o iotest io.c
*/
#include <assert.h>
#include <unistd.h>
#include <string.h>
#include <fcntl.h>
#include <sys/time.h>
#include <assert.h>
#include <stdlib.h>
#include <stdint.h>
#include <stdio.h>
static int c = 0;
static int tsize = 1000 * 1048576;
static const char path[] = "/tmp/wt.dat";
static char buf[65536];
static uint64_t now(void) {
struct timeval tv;
if (gettimeofday(&tv, NULL))
abort();
return tv.tv_sec * 1000000ULL + tv.tv_usec;
}
static void writetest(int size, size_t bsize)
{
int i;
uint64_t start, end;
double elapsed;
double mbps;
assert(bsize <= sizeof buf);
int fd = open(path, O_CREAT|O_WRONLY, 0644);
if (fd < 0) {
perror("open failed");
exit(254);
}
start = now();
for (i = 0; i < size; i += bsize) {
int rv = write(fd, buf, bsize);
if (c++ % 2000 == 0) fprintf(stderr, ".");
if (rv < 0) {
perror("write failed");
exit(254);
}
}
close(fd);
#ifndef NSYNC
# ifdef __linux__
fdatasync(fd);
# else
fsync(fd);
# endif
#endif /* SYNC */
end = now();
elapsed = (end - start) / 1e6;
mbps = ((tsize/elapsed)) / 1048576;
fprintf(stderr, "\nWrote %d bytes in %03fs using %ld byte buffers: %03fmB/s\n", size, elapsed, bsize, mbps);
}
void readtest(int size, size_t bsize)
{
int i;
uint64_t start, end;
double elapsed;
double mbps;
assert(bsize <= sizeof buf);
int fd = open(path, O_RDONLY, 0644);
if (fd < 0) {
perror("open failed");
exit(254);
}
start = now();
for (i = 0; i < size; i += bsize) {
int rv = read(fd, buf, bsize);
if (rv < 0) {
perror("write failed");
exit(254);
}
}
close(fd);
end = now();
elapsed = (end - start) / 1e6;
mbps = ((tsize/elapsed)) / 1048576;
fprintf(stderr, "Read %d bytes in %03fs using %ld byte buffers: %03fmB/s\n", size, elapsed, bsize, mbps);
}
void cleanup() {
unlink(path);
}
int main()
{
int i;
int bsizes[] = {1024, 4096, 8192, 16384, 32768, 65536, 0};
for (i = 0; bsizes[i] != 0; i++) {
writetest(tsize, bsizes[i]);
}
for (i = 0; bsizes[i] != 0; i++) {
readtest(tsize, bsizes[i]);
}
atexit(cleanup);
return 0;
}