void perfmon_init(void)
{
size_t i;
long nr;
if (cpu_type == CPU_TIMER_INT)
return;
if (!no_xen) {
xen_ctx = xmalloc(sizeof(struct child));
xen_ctx->pid = getpid();
xen_ctx->up_pipe[0] = -1;
xen_ctx->up_pipe[1] = -1;
xen_ctx->sigusr1 = 0;
xen_ctx->sigusr2 = 0;
xen_ctx->sigterm = 0;
create_context(xen_ctx);
write_pmu(xen_ctx);
load_context(xen_ctx);
return;
}
nr = sysconf(_SC_NPROCESSORS_ONLN);
if (nr == -1) {
fprintf(stderr, "Couldn't determine number of CPUs.\n");
exit(EXIT_FAILURE);
}
nr_cpus = nr;
children = xmalloc(sizeof(struct child) * nr_cpus);
bzero(children, sizeof(struct child) * nr_cpus);
for (i = 0; i < nr_cpus; ++i) {
int ret;
if (pipe(children[i].up_pipe)) {
perror("Couldn't create child pipe");
exit(EXIT_FAILURE);
}
ret = fork();
if (ret == -1) {
perror("Couldn't fork perfmon child");
exit(EXIT_FAILURE);
} else if (ret == 0) {
close(children[i].up_pipe[0]);
run_child(i);
} else {
children[i].pid = ret;
close(children[i].up_pipe[1]);
printf("Waiting on CPU%d\n", (int)i);
wait_for_child(&children[i]);
}
}
}
static void run_child(size_t cpu)
{
struct child * self = &children[cpu];
self->pid = getpid();
self->sigusr1 = 0;
self->sigusr2 = 0;
self->sigterm = 0;
inner_child = self;
if (atexit(close_pipe)){
close_pipe();
exit(EXIT_FAILURE);
}
umask(0);
/* Change directory to allow directory to be removed */
if (chdir("/") < 0) {
perror("Unable to chdir to \"/\"");
exit(EXIT_FAILURE);
}
setup_signals();
set_affinity(cpu);
create_context(self);
write_pmu(self);
load_context(self);
notify_parent(self, cpu);
/* Redirect standard files to /dev/null */
freopen( "/dev/null", "r", stdin);
freopen( "/dev/null", "w", stdout);
freopen( "/dev/null", "w", stderr);
for (;;) {
sigset_t sigmask;
sigfillset(&sigmask);
sigdelset(&sigmask, SIGUSR1);
sigdelset(&sigmask, SIGUSR2);
sigdelset(&sigmask, SIGTERM);
if (self->sigusr1) {
perfmon_start_child(self->ctx_fd);
self->sigusr1 = 0;
}
if (self->sigusr2) {
perfmon_stop_child(self->ctx_fd);
self->sigusr2 = 0;
}
sigsuspend(&sigmask);
}
}
static void run_child(size_t cpu)
{
struct child * self = &children[cpu];
self->pid = getpid();
self->sigusr1 = 0;
self->sigusr2 = 0;
self->sigterm = 0;
setup_signals();
set_affinity(cpu);
create_context(self);
write_pmu(self);
load_context(self);
notify_parent(self, cpu);
for (;;) {
sigset_t sigmask;
sigfillset(&sigmask);
sigdelset(&sigmask, SIGUSR1);
sigdelset(&sigmask, SIGUSR2);
sigdelset(&sigmask, SIGTERM);
if (self->sigusr1) {
printf("PFM_START on CPU%d\n", (int)cpu);
fflush(stdout);
perfmon_start_child(self->ctx_fd);
self->sigusr1 = 0;
}
if (self->sigusr2) {
printf("PFM_STOP on CPU%d\n", (int)cpu);
fflush(stdout);
perfmon_stop_child(self->ctx_fd);
self->sigusr2 = 0;
}
sigsuspend(&sigmask);
}
}
