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Peter Stuge
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examples: Add sam3u_benchmark isochronous example by Harald Welte
Copied with the author's permission under LGPL-2.1 from usb-benchmark-project/host/benchmark.c in git://git.gnumonks.org/sam3u-tests.git commit 74959f7ee88f1597286cd435f312a8ff52c56b7e 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.
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‎.gitignore

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@@ -27,6 +27,7 @@ doxygen.cfg
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examples/listdevs
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examples/dpfp
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examples/dpfp_threaded
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examples/sam3u_benchmark
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*.exe
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*.pc
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ChangeLog

‎examples/Makefile.am

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@@ -13,4 +13,7 @@ dpfp_threaded_SOURCES = dpfp_threaded.c
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dpfp_threaded_CFLAGS = $(THREAD_CFLAGS) $(AM_CFLAGS)
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noinst_PROGRAMS += dpfp_threaded
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endif
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sam3u_benchmark_SOURCES = sam3u_benchmark.c
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noinst_PROGRAMS += sam3u_benchmark
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endif

‎examples/sam3u_benchmark.c

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

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