Gilles Chanteperdrix wrote:
> [EMAIL PROTECTED] wrote:
> > Index: xenomai/src/testsuite/irqbench/irqbench.c
> > ===================================================================
> > --- /dev/null
> > +++ xenomai/src/testsuite/irqbench/irqbench.c
> > @@ -0,0 +1,301 @@
> > +/*
> > + * Copyright (C) 2006 Jan Kiszka <[EMAIL PROTECTED]>.
> > + *
> > + * Xenomai is free software; you can redistribute it and/or modify it
> > + * under the terms of the GNU General Public License as published by
> > + * the Free Software Foundation; either version 2 of the License, or
> > + * (at your option) any later version.
> > + *
> > + * Xenomai 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
> > + * General Public License for more details.
> > + *
> > + * You should have received a copy of the GNU General Public License
> > + * along with Xenomai; if not, write to the Free Software Foundation,
> > + * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
> > + */
> > +
> > +#include <limits.h>
> > +#include <stdio.h>
> > +#include <stdlib.h>
> > +#include <string.h>
> > +#include <signal.h>
> > +#include <unistd.h>
> > +#include <sys/io.h>
> > +#include <sys/mman.h>
> > +
> > +
> > +#define SERPORT 0
> > +#define PARPORT 1
> > +
> > +/* --- Serial port --- */
> > +
> > +#define MCR_DTR 0x01
> > +#define MCR_RTS 0x02
> > +#define MCR_OUT2 0x08
> > +
> > +#define MSR_DELTA 0x0F
> > +
> > +#define LCR(base) (base + 3) /* Line Control Register */
> > +#define MCR(base) (base + 4) /* Modem Control Register */
> > +#define LSR(base) (base + 5) /* Line Status Register */
> > +#define MSR(base) (base + 6) /* Modem Status Register */
> > +
> > +/* --- Parallel port --- */
> > +
> > +#define CTRL_INIT 0x04
> > +
> > +#define STAT_STROBE 0x10
> > +
> > +#define DATA(base) (base + 0) /* Data register */
> > +#define STAT(base) (base + 1) /* Status register */
> > +#define CTRL(base) (base + 2) /* Control register */
> > +
> > +double tsc2ns_scale;
> > +long long min_lat = LLONG_MAX;
> > +long long max_lat = LLONG_MIN;
> > +long long avg_lat = 0;
> > +long outer_loops = 0;
> > +int warmup = 1;
> > +
> > +static inline long long rdtsc(void)
> > +{
> > + unsigned long long tsc;
> > +
> > + __asm__ __volatile__("rdtsc" : "=A" (tsc));
> > + return tsc;
> > +}
> > +
> > +
> > +static long tsc2ns(long long tsc)
> > +{
> > + if ((tsc > LONG_MAX) || (tsc < LONG_MIN)) {
> > + fprintf(stderr, "irqbench: overflow (%lld ns)!\n",
> > + (long long)(tsc2ns_scale * (double)tsc));
> > + exit(2);
> > + }
> > + return (long)(tsc2ns_scale * (double)tsc);
> > +}
> > +
> > +
> > +static inline long long ns2tsc(long long ns)
> > +{
> > + return (long long)(((double)ns) / tsc2ns_scale);
> > +}
> > +
> > +
> > +void calibrate_tsc(void)
> > +{
> > + FILE *proc;
> > + char *lineptr = NULL;
> > + size_t len;
> > + double cpu_mhz;
> > +
> > + proc = fopen("/proc/cpuinfo", "r");
> > + if (proc == NULL) {
> > + perror("irqbench: Unable to open /proc/cpuinfo");
> > + exit(1);
> > + }
> > +
> > + while (getline(&lineptr, &len, proc) != -1)
> > + if (strncmp(lineptr, "cpu MHz", 7) == 0) {
> > + sscanf(strchr(lineptr, ':') + 1, "%lf", &cpu_mhz);
> > + break;
> > + }
> > +
> > + if (lineptr)
> > + free(lineptr);
> > + fclose(proc);
> > +
> > + printf("CPU frequency: %.3lf MHz\n", cpu_mhz);
> > +
> > + tsc2ns_scale = 1000.0 / cpu_mhz;
> > +}
> > +
> > +
> > +void sighand(int signal)
> > +{
> > + if (!warmup) {
> > + avg_lat /= outer_loops;
> > + printf("---\n%.3f / %.3f / %.3f us\n",
> > + ((double)min_lat) / 1000.0, ((double)avg_lat) / 1000.0,
> > + ((double)max_lat) / 1000.0);
> > + }
> > + exit(0);
> > +}
> > +
> > +
> > +int main(int argc, char *argv[])
> > +{
> > + int port_type = SERPORT;
> > + unsigned long port_ioaddr = 0x3F8;
> > + long long period = 100000;
> > + long long timeout;
> > + long long start, delay;
> > + unsigned int toggle;
> > + int trigger_trace = 0;
> > + int c;
> > +
> > +
> > + signal(SIGINT, sighand);
> > + signal(SIGTERM, sighand);
> > + signal(SIGHUP, sighand);
> > + signal(SIGALRM, sighand);
> > +
> > + calibrate_tsc();
> > +
> > + while ((c = getopt(argc,argv,"p:T:o:a:f")) != EOF)
> > + switch (c) {
> > + case 'p':
> > + period = atoi(optarg) * 1000;
> > + break;
> > +
> > + case 'T':
> > + alarm(atoi(optarg));
> > + break;
> > +
> > + case 'o':
> > + port_type = atoi(optarg);
> > + break;
> > +
> > + case 'a':
> > + port_ioaddr = strtol(optarg, NULL,
> > + (strncmp(optarg, "0x", 2) == 0) ? 16 : 10);
> > + break;
> > +
> > + case 'f':
> > + trigger_trace = 1;
> > + break;
> > +
> > + default:
> > + fprintf(stderr, "usage: irqbench [options]\n"
> > + " [-p <period_us>] # signal period,
> default=100 us\n"
> > + " [-T <test_duration_seconds>] # default=0, so
> ^C to end\n"
> > + " [-o <port_type>] # 0=serial
> (default), 1=parallel\n"
> > + " [-a <port_io_address>] # default=0x3f8\n"
> > + " [-f] # freeze trace
> for each new max latency\n");
> > + exit(2);
> > + }
> > +
> > + if (iopl(3) < 0) {
> > + fprintf(stderr, "irqbench: superuser permissions required\n");
> > + exit(1);
> > + }
> > + mlockall(MCL_CURRENT | MCL_FUTURE);
> > +
> > + switch (port_type) {
> > + case SERPORT:
> > + toggle = MCR_OUT2;
> > + inb(MSR(port_ioaddr));
> > + break;
> > +
> > + case PARPORT:
> > + toggle = 0xAA;
> > + outb(0xAA, DATA(port_ioaddr));
> > + outb(CTRL_INIT, CTRL(port_ioaddr));
> > + break;
> > +
> > + default:
> > + fprintf(stderr, "irqbench: invalid port type\n");
> > + exit(1);
> > + }
> > +
> > + period = ns2tsc(period);
> > +
> > + printf("Port type: %s\n"
> > + "Port address: 0x%lx\n\n",
> > + (port_type == SERPORT) ? "serial" : "parallel", port_ioaddr);
> > +
> > + printf("Waiting on target...\n");
> > +
> > + while (1)
> > + if (port_type == SERPORT) {
> > + toggle ^= MCR_RTS;
> > + outb(toggle, MCR(port_ioaddr));
> > + usleep(100000);
> > + if ((inb(MSR(port_ioaddr)) & MSR_DELTA) != 0)
> > + break;
> > + } else {
> > + int status = inb(STAT(port_ioaddr));
> > +
> > + toggle ^= 0xFF;
> > + outb(toggle, DATA(port_ioaddr));
> > + if (inb(STAT(port_ioaddr)) != status)
> > + break;
> > + }
> > +
> > + printf("Warming up...\n");
> > +
> > + while (1) {
> > + long long loop_timeout = rdtsc() + ns2tsc(1000000000LL);
> > + long loop_avg = 0;
> > + int inner_loops;
> > +
> > + for (inner_loops = 0; rdtsc() < loop_timeout; inner_loops++) {
> > + long lat;
> > +
> > + __asm__ __volatile__("cli");
> > +
> > + if (port_type == SERPORT) {
> > + start = rdtsc();
> > +
> > + toggle ^= MCR_RTS;
> > + outb(toggle, MCR(port_ioaddr));
> > +
> > + timeout = start + period * 100;
> > + while (((inb(MSR(port_ioaddr)) & MSR_DELTA) == 0) &&
> > + (rdtsc() < timeout));
> > +
> > + delay = rdtsc() - start;
> > + } else {
> > + int status = inb(STAT(port_ioaddr));
> > +
> > + start = rdtsc();
> > +
> > + toggle ^= 0xFF;
> > + outb(toggle, DATA(port_ioaddr));
> > +
> > + timeout = start + period * 100;
> > + while ((inb(STAT(port_ioaddr)) == status) &&
> > + (rdtsc() < timeout));
> > +
> > + delay = rdtsc() - start;
> > + }
> > +
> > + if (!warmup) {
> > + lat = tsc2ns(delay);
> > +
> > + loop_avg += lat;
> > + if (lat < min_lat)
> > + min_lat = lat;
> > + if (lat > max_lat) {
> > + max_lat = lat;
> > + if (trigger_trace) {
> > + if (port_type == SERPORT) {
> > + toggle ^= MCR_DTR;
> > + outb(toggle, MCR(port_ioaddr));
> > + } else {
> > + // todo
> > + }
> > + }
> > + }
> > + }
> > +
> > + __asm__ __volatile__("sti");
> > +
> > + while (rdtsc() < start + period);
> > + }
> > + if (!warmup) {
> > + loop_avg /= inner_loops;
> > +
> > + printf("%.3f / %.3f / %.3f us\n",
> > + ((double)min_lat) / 1000.0, ((double)loop_avg) / 1000.0,
> > + ((double)max_lat) / 1000.0);
> > +
> > + avg_lat += loop_avg;
> > + outer_loops++;
> > + } else
> > + warmup = 0;
> > + }
> > +}
>
> Is there no way to make this code easier to port for example by using
> native or posix services for timings measurement and by abstracting the
> non portable part and moving them to include/asm-i386 ?This tool is intentionally left Xenomai-free. You can put it on any x86 box around (and I assume that there is almost always some...) and run the test. Thus, no need for a second RT-patched system. Anyway, suggestions or patches to add a porting layer are welcome. The following points need to be addressed: time measuring, irq protection, hardware access. I just wonder if this is worth the effort. > > Also note that calling printf from a signal handler risk deadlocking if > the signal handler get called on the return path of the write call that > take place in the middle of a printf call on the main thread. > Ok, then we also need a fix for the latency test (this is where I grabbed that pattern from). Is there a high risk that this locks up? I wonder why I never observed or heard of problems with latency. Jan
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