Re: Massive performance loss from OS::sleep hack

On Saturday 15 September 2007 10:50:50 pm Kurt Miller wrote:
The following are programs I wrote when I isolated the problem.
If the c program runs ok on 7.0 for both single cpu and mp then
remove the os_sleep() and try the java program. If that works too
then you're clear to make the os_sleep() hack only apply to <
7.0 and still be able to pass the certification tests.

Sorry copy/paste glitch. He is the c program again:

#include <pthread.h>
#include <unistd.h>
#include <signal.h>
#include <inttypes.h>
#include <time.h>
#include <stdio.h>
#include <stdlib.h>
#include <errno.h>

volatile int init=0;
volatile int interrupt=0;

static void *
yielder(void *arg)
{
init = 1;
while (1) {
pthread_yield();
}
}

static void
sighandler(int sig)
{
interrupt = 1;
printf("sighandler\n");
}

static void
waitForInit() {
struct timespec t, rt;

while (init == 0) {
t.tv_sec = 0;
t.tv_nsec = 100000;
nanosleep(&t, &rt);
}
}

static void
waitForInterrupt() {
struct timespec t, rt;

while (interrupt == 0) {
t.tv_sec = 0;
t.tv_nsec = 100000;
nanosleep(&t, &rt);
}
}

int
main(int argc, char *argv[])
{
pthread_t yldr;
pthread_attr_t attr;
struct sigaction act;

/* Install a signal handler for SIGUSR1 */
sigemptyset (&act.sa_mask);
sigaddset (&act.sa_mask, SIGUSR1);
act.sa_handler = sighandler;
act.sa_flags = 0;
sigaction (SIGUSR1, &act, NULL);

pthread_attr_init(&attr);
pthread_attr_setschedpolicy(&attr, SCHED_FIFO);

pthread_create(&yldr, &attr, yielder, NULL);
pthread_setprio(yldr, 16);
waitForInit();
if(pthread_kill(yldr, SIGUSR1) != 0)
printf("pthread_kill failed with errno = %d\n", errno);
waitForInterrupt();
}
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