/*
* libusb example program to measure Atmel SAM3U isochronous performance
* Copyright (C) 2012 Harald Welte <laforge@gnumonks.org>
*
* Copied with the author's permission under LGPL-2.1 from
* http://git.gnumonks.org/cgi-bin/gitweb.cgi?p=sam3u-tests.git;a=blob;f=usb-benchmark-project/host/benchmark.c;h=74959f7ee88f1597286cd435f312a8ff52c56b7e
*
* An Atmel SAM3U test firmware is also available in the above repository.
*
* This 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 2.1 of the License, or (at your option) any later version.
*
* This 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 this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include <unistd.h>
#include <stdlib.h>
#include <stdio.h>
#include <errno.h>
#include <signal.h>
#include <libusb.h>
#define EP_DATA_IN 0x82
#define EP_ISO_IN 0x86
static int do_exit = 0;
static struct libusb_device_handle *devh = NULL;
static unsigned long num_bytes = 0, num_xfer = 0;
static struct timeval tv_start;
static void cb_xfr(struct libusb_transfer *xfr)
{
unsigned int i;
if (xfr->status != LIBUSB_TRANSFER_COMPLETED) {
fprintf(stderr, "transfer status %d\n", xfr->status);
libusb_free_transfer(xfr);
exit(3);
}
if (xfr->type == LIBUSB_TRANSFER_TYPE_ISOCHRONOUS) {
for (i = 0; i < xfr->num_iso_packets; i++) {
struct libusb_iso_packet_descriptor *pack = &xfr->iso_packet_desc[i];
if (pack->status != LIBUSB_TRANSFER_COMPLETED) {
fprintf(stderr, "Error: pack %u status %d\n", i, pack->status);
exit(5);
}
printf("pack%u length:%u, actual_length:%u\n", i, pack->length, pack->actual_length);
}
}
printf("length:%u, actual_length:%u\n", xfr->length, xfr->actual_length);
for (i = 0; i < xfr->actual_length; i++) {
printf("%02x", xfr->buffer[i]);
if (i % 16)
printf("\n");
else if (i % 8)
printf(" ");
else
printf(" ");
}
num_bytes += xfr->actual_length;
num_xfer++;
if (libusb_submit_transfer(xfr) < 0) {
fprintf(stderr, "error re-submitting URB\n");
exit(1);
}
}
static int benchmark_in(uint8_t ep)
{
static uint8_t buf[2048];
static struct libusb_transfer *xfr;
int num_iso_pack = 0;
if (ep == EP_ISO_IN)
num_iso_pack = 16;
xfr = libusb_alloc_transfer(num_iso_pack);
if (!xfr)
return -ENOMEM;
if (ep == EP_ISO_IN) {
libusb_fill_iso_transfer(xfr, devh, ep, buf,
sizeof(buf), num_iso_pack, cb_xfr, NULL, 0);
libusb_set_iso_packet_lengths(xfr, sizeof(buf)/num_iso_pack);
} else
libusb_fill_bulk_transfer(xfr, devh, ep, buf,
sizeof(buf), cb_xfr, NULL, 0);
gettimeofday(&tv_start, NULL);
/* NOTE: To reach maximum possible performance the program must
* submit *multiple* transfers here, not just one.
*
* When only one transfer is submitted there is a gap in the bus
* schedule from when the transfer completes until a new transfer
* is submitted by the callback. This causes some jitter for
* isochronous transfers and loss of throughput for bulk transfers.
*
* This is avoided by queueing multiple transfers in advance, so
* that the host controller is always kept busy, and will schedule
* more transfers on the bus while the callback is running for
* transfers which have completed on the bus.
*/
return libusb_submit_transfer(xfr);
}
static void measure(void)
{
struct timeval tv_stop;
unsigned int diff_msec;
gettimeofday(&tv_stop, NULL);
diff_msec = (tv_stop.tv_sec - tv_start.tv_sec)*1000;
diff_msec += (tv_stop.tv_usec - tv_start.tv_usec)/1000;
printf("%lu transfers (total %lu bytes) in %u miliseconds => %lu bytes/sec\n",
num_xfer, num_bytes, diff_msec, (num_bytes*1000)/diff_msec);
}
static void sig_hdlr(int signum)
{
switch (signum) {
case SIGINT:
measure();
do_exit = 1;
break;
}
}
int main(int argc, char **argv)
{
int rc;
struct sigaction sigact;
sigact.sa_handler = sig_hdlr;
sigemptyset(&sigact.sa_mask);
sigact.sa_flags = 0;
sigaction(SIGINT, &sigact, NULL);
rc = libusb_init(NULL);
if (rc < 0) {
fprintf(stderr, "Error initializing libusb: %s\n", libusb_error_name(rc));
exit(1);
}
devh = libusb_open_device_with_vid_pid(NULL, 0x16c0, 0x0763);
if (!devh) {
fprintf(stderr, "Error finding USB device\n");
goto out;
}
rc = libusb_claim_interface(devh, 2);
if (rc < 0) {
fprintf(stderr, "Error claiming interface: %s\n", libusb_error_name(rc));
goto out;
}
benchmark_in(EP_ISO_IN);
while (!do_exit) {
rc = libusb_handle_events(NULL);
if (rc != LIBUSB_SUCCESS)
break;
}
/* Measurement has already been done by the signal handler. */
libusb_release_interface(devh, 0);
out:
if (devh)
libusb_close(devh);
libusb_exit(NULL);
return rc;
}
