On Wed, 19 Aug 2015 04:11:31 -0700
Yale Zhang <yzhang1985@xxxxxxxxx> wrote:
> SMB developers/users,
>
> I'm experiencing a strange bottleneck when my files are mounted as SMB
> 2.0. When I launch multiple processes in parallel for benchmarking,
> only the 1st one starts, and the rest won't start until the 1st one
> finishes:
>
> ---------------------------------------test
> programs--------------------------------
> #!/bin/sh
> ./a.out&
> ./a.out&
> ./a.out&
> wait
>
> a.out is just a C program like this:
>
> int main()
> {
> printf("greetings\n");
> while (true);
> return 0;
> }
>
> Apparently, this only affects SMB 2.0. I tried it with SMB 2.1, SMB
> 3.0, & SMB 3.02, and everything starts in parallel as expected.
>
> I'm assuming SMB 3 and especially SMB 2.1 would share a common
> implementation. How could 2.0 have the problem but not 3? It almost
> seems the bottleneck is a feature instead of a bug? 8(
>
> Can it still be fixed?
>
> -Yale
Probably. It'd be interesting to see what the other tasks are blocking
on. After firing up the second one can you run:
# cat /proc/<pid of second a.out>/stack
...and paste the stack trace here? That should tell us what those other
processes are doing.
--
Jeff Layton <jlayton@xxxxxxxxxxxxxxx>
--
To unsubscribe from this list: send the line "unsubscribe linux-cifs" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
