[zeromq-dev] HWM default

Martin Sustrik sustrik at 250bpm.com
Thu May 12 08:56:47 CEST 2011

On 05/09/2011 02:41 PM, Paul Colomiets wrote:

> Well, I have no practical experience, but a lot of alloc_assert's in the
> code says that it will be aborted. BTW, it will be so not only if
> overcommit_memory is set right, but also if ulimit is set for the
> application's memory. Which is awfully bad IMO.

What else would you do if you run out of memory? Any recovery mechanism 
in user space is likely to fail because there's no memory available :) 
Killing (and possibly restarting) the app seems like a reasonable option 
to me.

>     We should distinguish deadlocks inside 0MQ (such as one introduced
>     by the shutdown functionality) which should be considered 0MQ bugs
>     and deadlocks in applications on top of 0MQ (the ones we are
>     discussing now) which should be considered application bugs.
> Don't see why shutdown would introduce deadlocks inside 0mq

I referred to our old discussion.

> But thinking of it a bit more about default HWM, it seems that issues
> are same using TCP or unix domain sockets. And for future in-kernel
> implementation HWM should probably always be set. So it's probably ok to
> have reasonable default.

Yes. With kernel implementation the buffers *are* TCP buffers and HWM 
*is* the TCP buffer size. So there's no way to have it unlimited.


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