Re: [Qemu-devel] Qemu and heavily increased RSS usage

[Michael S. Tsirkin]

On Thu, Jun 23, 2016 at 11:57:45AM +0200, Peter Lieven wrote:
> Am 21.06.2016 um 15:18 schrieb Dr. David Alan Gilbert:
> > * Peter Lieven (address@hidden) wrote:
> > > Hi,
> > > 
> > > while upgrading from Qemu 2.2.0 to Qemu 2.5.1.1 I noticed that the RSS 
> > > memory usage has heavily increased.
> > > We use hugepages so the RSS memory does not include VM memory. In Qemu 
> > > 2.2.0 it used to be ~30MB per vServer
> > > and increased to up to 300 - 400MB for Qemu 2.5.1.1 (same with master). 
> > > The memory increases over time, but seems
> > > not to grow indefinetly. I tried to bisect, but had no result so far that 
> > > made sense. I also tried valgrind / massif, but
> > > valgrind does not see the allocation (at least at exit) and massif fails 
> > > to rund due to - so it pretends - heap corruption.
> > > 
> > > Any help or ideas how to debug further would be appreciated.
> > I think I'd try stripping devices off; can you get a similar difference
> > to happen with a guest with no USB, no hugepages, no VGA and a simple
> > locally stored IDE disk?
> 
> From what I have debugged so far, it seems to be related to virtio-net. With 
> that knowledge I will try to bisect again.
> 
> Peter
> 

Interesting. You can try attaching vhost  to tap so virtio net does not
process packets in qemu, for comparison.

-- 
MST