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/* See LICENSE file for copyright and license details. */
#define _GNU_SOURCE
#include <fcntl.h>
#include <limits.h>
#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#include <unistd.h>
#ifndef CAPACITY
# define CAPACITY (1 << 20)
#endif
int
main(int argc, char *argv[])
{
static char buf[1 << 16];
int rw1[2], rw2[2], n = 0, m;
ssize_t r, p, w;
size_t sum = 0, totsum = 0;
struct timespec start, end;
double rate;
if (!argc)
*argv = "limit";
if (pipe(rw1) || fcntl(*rw1, F_SETPIPE_SZ, CAPACITY) != CAPACITY)
goto fail;
if (pipe(rw2) || fcntl(*rw2, F_SETPIPE_SZ, CAPACITY) != CAPACITY)
goto fail;
for (n = CAPACITY; n; n -= (int)r)
if ((r = write(rw1[1], buf, n)) < 0)
goto fail;
if (clock_gettime(CLOCK_MONOTONIC, &start))
goto fail;
for (;;) {
r = splice(rw1[0], NULL, rw2[1], NULL, CAPACITY, 0);
if (r <= 0) {
if (r < 0)
goto fail;
goto done;
}
for (p = 0; p < r; p += w) {
w = splice(rw2[0], NULL, rw1[1], NULL, r - p, 0);
if (w <= 0) {
if (w < 0)
goto fail;
goto done;
}
}
sum += (size_t)r << 1;
if (++n == 100000) {
if (clock_gettime(CLOCK_MONOTONIC, &end))
goto fail;
n = 0;
start.tv_sec = end.tv_sec - start.tv_sec;
start.tv_nsec = end.tv_nsec - start.tv_nsec;
rate = (double)start.tv_nsec;
rate /= 1000000000.;
rate += start.tv_sec;
rate = (double)sum / rate;
rate /= 1000000000.;
totsum += sum;
sum = 0;
dprintf(STDERR_FILENO, " %lf GB/s\033[K\n\033[A", rate);
start = end;
}
}
done:
return 0;
fail:
perror(*argv);
return 1;
}
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