Hi Christoffer,

On Wed, Jan 2, 2013 at 7:17 PM, Christoffer Dall <cd...@cs.columbia.edu>wrote:

>
> The culprit seems to be when the process runs out of virtual address
> space on 32-bit systems due to some subsystem (virtio?) creating a
> large number of pthreads under heavy workloads.
>
>
One possibility - qemu uses coroutines for IO. There are various backends
for coroutines, and the qemu configure script will try to choose the best
one. Perhaps your environment is lacking system calls such as makecontext
and the configure script is falling back to a coroutine backend using
pthreads. I've found that this can cause 50000+ threads to be spawned just
during a loadvm operation, for instance.

If this fits the symptoms, try using the --with-coroutine option during
qemu configure.

Regards

Adrian

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