Re: Lots of connections led oxenstored stuck

[Joe Jin <joe.jin@oracle.com>]

On 08/08/14 17:37, Dave Scott wrote:
> 
> On 8 Aug 2014, at 09:35, Liuqiming (John) <john.liuqiming@huawei.com> wrote:
> 
>> In oxenstored it use "select" for incoming socket, so I don't think it can handle more than 1024 socket connections. 
> 
> That’s true.

The problem is when oxenstored does not respond any request anymore even all
thread exited, with my reproducer, when you executed it and all threads exited,
"xm list -l" will stuck.

Thanks,
Joe
> 
> In the long term I’d like to use Lwt which internally uses libev and has a more scalable event loop.
> 
> In the short term I think Zheng Li (cc:d) may have a prototype patch to work around this issue. Is this right, Zheng?
> 
> Cheers,
> Dave
> 
>>
>>> -----Original Message-----
>>> From: xen-devel-bounces@lists.xen.org
>>> [mailto:xen-devel-bounces@lists.xen.org] On Behalf Of Joe Jin
>>> Sent: Friday, August 08, 2014 3:01 PM
>>> To: David Scott; Luis R. Rodriguez; Ian Jackson
>>> Cc: xen-devel
>>> Subject: [Xen-devel] Lots of connections led oxenstored stuck
>>>
>>> Hi,
>>>
>>> During internal test on Xen-4.3-stable we found sometime when restarted
>>> Xen, it stuck and does not response any request, xenstored.log filled
>>> out below stuff:
>>> [20140702T21:00:41.564Z|error|xenstored] caught exception
>>> Unix.Unix_error(15, "accept", "")
>>>
>>> I created reproducer which will create 2000 connections to oxenstored,
>>> after
>>> ran the reproducer, "xm list --long" will stuck, oxenstored does not
>>> response anymore, same test case passed when use xenstored, any input
>>> will appreciate!
>>>
>>> /*
>>> * This program used to test oxenstored connections stuck issue.
>>> * please compile by below command:
>>> *	gcc -o client client.c -lpthread
>>> */
>>> #include <stdio.h>
>>> #include <sys/socket.h>
>>> #include <sys/un.h>
>>> #include <unistd.h>
>>> #include <string.h>
>>> #include <pthread.h>
>>> #include <stdlib.h>
>>> #include <errno.h>
>>>
>>>
>>> void *main_thread(void *arg)
>>> {
>>> 	struct sockaddr_un address;
>>> 	int socket_fd, nbytes;
>>> 	char buffer[256];
>>> 	int i;
>>> 	extern int errno;
>>>
>>> 	memcpy(&i, arg, sizeof(i));
>>> 	socket_fd = socket(PF_UNIX, SOCK_STREAM, 0);
>>> 	if (socket_fd < 0) {
>>> 		fprintf(stderr, "socket() %dth failed, errno=%d\n", i, errno);
>>> 		return;
>>> 	}
>>> 	fprintf(stderr, "socket() %dth ok!\n", i);
>>>
>>> 	/* start with a clean address structure */
>>> 	memset(&address, 0, sizeof(struct sockaddr_un));
>>>
>>> 	address.sun_family = AF_UNIX;
>>> 	snprintf(address.sun_path, 1024, "/var/run/xenstored/socket");
>>>
>>> 	if (connect(socket_fd,
>>> 		    (struct sockaddr *) &address,
>>> 		    sizeof(struct sockaddr_un)) != 0) {
>>> 		fprintf(stderr, "connect() %d failed, error=%d", i, errno);
>>> 		return;
>>> 	}
>>> 	fprintf(stderr, "connec() %dth ok!\n", i);
>>>
>>> 	while (1)
>>> 		sleep(1);
>>> 	if (arg) {
>>> 		free(arg);
>>> 		arg = NULL;
>>> 	}
>>>
>>> 	return;
>>> }
>>>
>>> int main(void)
>>> {
>>> 	int i;
>>> 	for (i = 0; i < 2000; i++) {
>>> 		void *arg = malloc(sizeof(i));
>>> 		memset(arg, 0, sizeof(i));
>>> 		memcpy(arg, &i, sizeof(i));
>>> 		pthread_t thread;
>>> 		if (pthread_create(&thread, NULL, main_thread, arg) != 0) {
>>> 			perror("pthread_create:");
>>> 			break;
>>> 		}
>>> 	}
>>> 	/* Wait all children exit */
>>> 	sleep(3);
>>> 	return 0;
>>> }
>>> /* end */
>>>
>>> Thanks,
>>> Joe
>>>
>>> _______________________________________________
>>> Xen-devel mailing list
>>> Xen-devel@lists.xen.org
>>> http://lists.xen.org/xen-devel
> 
> 
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@lists.xen.org
> http://lists.xen.org/xen-devel
>