port-amd64/46581: Continuous pthread_create may fail on amd64

[naruse%airemix.jp@localhost]

>Number:         46581
>Category:       port-amd64
>Synopsis:       Continuous pthread_create may fail on amd64
>Confidential:   no
>Severity:       non-critical
>Priority:       medium
>Responsible:    port-amd64-maintainer
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Mon Jun 11 03:55:00 +0000 2012
>Originator:     Yui NARUSE
>Release:        6.99.7
>Organization:
>Environment:
NetBSD kelvena.airemix.net 6.99.7 NetBSD 6.99.7 (GENERIC) #2: Thu May 17 
14:42:34 JST 2012  
naruse%kelvena.airemix.net@localhost:/usr/obj/sys/arch/amd64/compile/GENERIC 
amd64
>Description:
Below program fails on amd64 as following:

% cc -pthread thr.c&&./a.out
pthread_create: Resource temporarily unavailable
zsh: abort (core dumped)  ./a.out

On the environment, ulimit -u is 160.
But it won't fail on i386.
It won't fail if sched_yield() is not commented out.
So it seems something is wrong.

#include <pthread.h>
#include <stdlib.h>
#define THREAD_COUNT 161
void *dummy(void *p) {
    return NULL;
}
int main(void) {
    int i;
    pthread_t *threads = malloc(sizeof(pthread_t) * THREAD_COUNT);
    for (i = 0; i < THREAD_COUNT; i++) {
        if (pthread_create(&threads[i], NULL, dummy, &i)) {
            perror("pthread_create");
            abort();
        }   
        //sched_yield();
    }   
    return 0;
} 
>How-To-Repeat:

>Fix: