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/*
** GNU Pth - The GNU Portable Threads
** Copyright (c) 1999-2006 Ralf S. Engelschall <rse@engelschall.com>
**
** This file is part of GNU Pth, a non-preemptive thread scheduling
** library which can be found at http://www.gnu.org/software/pth/.
**
** 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307
** USA, or contact Ralf S. Engelschall <rse@engelschall.com>.
**
** test_uctx.c: Pth test program (user-space context switching)
*/
/* ``Engineering does not require science.
Science helps a lot, but people built
perfectly good brick walls long before
they knew why cement works.''
-- Alan Cox */
#include <stdio.h>
#include <time.h>
#include "pth.h"
volatile pth_uctx_t uctx[10];
/*
* Test 1: master and worker "threads"
*/
volatile int worker_done[10];
static void worker(void *ctx)
{
volatile int n = (int)ctx;
volatile int i = 0;
fprintf(stderr, "worker #%d: enter\n", n);
for (i = 0; i < 100; i++) {
fprintf(stderr, "worker #%d: working (step %d)\n", n, i);
pth_uctx_switch(uctx[n], uctx[0]);
}
worker_done[n] = TRUE;
fprintf(stderr, "worker #%d: exit\n", n);
return;
}
static void test_working(void)
{
volatile int i;
volatile int todo;
fprintf(stderr, "master: startup\n");
fprintf(stderr, "master: create contexts\n");
pth_uctx_create((pth_uctx_t *)&uctx[0]);
worker_done[0] = FALSE;
for (i = 1; i < 10; i++) {
worker_done[i] = FALSE;
pth_uctx_create((pth_uctx_t *)&uctx[i]);
pth_uctx_make(uctx[i], NULL, 32*1024, NULL, worker, (void *)i, uctx[0]);
}
do {
todo = 0;
for (i = 1; i < 10; i++) {
if (!worker_done[i]) {
fprintf(stderr, "master: switching to worker #%d\n", i);
pth_uctx_switch(uctx[0], uctx[i]);
fprintf(stderr, "master: came back from worker #%d\n", i);
todo = 1;
}
}
} while (todo);
fprintf(stderr, "master: destroy contexts\n");
for (i = 1; i < 10; i++)
pth_uctx_destroy(uctx[i]);
pth_uctx_destroy(uctx[0]);
fprintf(stderr, "master: exit\n");
return;
}
/*
* Test 2: raw switching performance
*/
#define DO_SWITCHES 10000000
time_t stat_start;
time_t stat_end;
volatile int stat_switched;
static void dummy(void *ctx)
{
while (1) {
stat_switched++;
pth_uctx_switch(uctx[1], uctx[0]);
}
return;
}
static void test_performance(void)
{
volatile int i;
pth_uctx_create((pth_uctx_t *)&uctx[0]);
pth_uctx_create((pth_uctx_t *)&uctx[1]);
pth_uctx_make(uctx[1], NULL, 32*1024, NULL, dummy, NULL, uctx[0]);
fprintf(stderr, "\n");
fprintf(stderr, "Performing %d user-space context switches... "
"be patient!\n", DO_SWITCHES);
stat_start = time(NULL);
stat_switched = 0;
for (i = 0; i < DO_SWITCHES; i++) {
stat_switched++;
pth_uctx_switch(uctx[0], uctx[1]);
}
stat_end = time(NULL);
pth_uctx_destroy(uctx[0]);
pth_uctx_destroy(uctx[1]);
fprintf(stderr, "We required %d seconds for performing the test, "
"so this means we can\n", (int)(stat_end-stat_start));
fprintf(stderr, "perform %d user-space context switches per second "
"on this platform.\n", DO_SWITCHES/(int)(stat_end-stat_start));
fprintf(stderr, "\n");
return;
}
int main(int argc, char *argv[])
{
test_working();
test_performance();
return 0;
}
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