[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [Qemu-devel] Qemu and heavily increased RSS usage
From: |
Dr. David Alan Gilbert |
Subject: |
Re: [Qemu-devel] Qemu and heavily increased RSS usage |
Date: |
Fri, 24 Jun 2016 10:57:55 +0100 |
User-agent: |
Mutt/1.6.1 (2016-04-27) |
* Peter Lieven (address@hidden) wrote:
> Am 24.06.2016 um 11:37 schrieb Stefan Hajnoczi:
> > On Wed, Jun 22, 2016 at 09:56:06PM +0100, Peter Maydell wrote:
> >> On 22 June 2016 at 20:55, Peter Lieven <address@hidden> wrote:
> >>> What makes the coroutine pool memory intensive is the stack size of 1MB
> >>> per
> >>> coroutine. Is it really necessary to have such a big stack?
> >> That reminds me that I was wondering if we should allocate
> >> our coroutine stacks with MAP_GROWSDOWN (though if we're
> >> not actually using 1MB of stack then it's only going to
> >> be eating virtual memory, not necessarily real memory.)
> > Yes, MAP_GROWSDOWN will not reduce RSS.
>
> Yes, I can confirm just tested...
>
> >
> > It's possible that we can reduce RSS usage of the coroutine pool but it
> > will require someone to profile the pool usage patterns.
>
> It would be interesting to see what stack size we really need. Is it possible
> to automatically detect this value (at compile time?)
>
> I can also confirm that the coroutine pool is the second major RSS user beside
> heap fragmentation.
But is it there stack? You said you tried marking GROWSDOWN, so can you check
/proc/../smaps and see how much of the Rss is the growsdown space?
Dave
> Lowering the mmap threshold of malloc to about 32k also gives good results.
> In this case there are very few active mappings in the running vServer, but
> the
> RSS is still at about 50MB (without coroutine pool). Maybe it would be good
> to identify which parts of Qemu malloc lets say >16kB and convert them to mmap
> if it is feasible.
>
> Peter
>
--
Dr. David Alan Gilbert / address@hidden / Manchester, UK
- [Qemu-devel] Qemu and heavily increased RSS usage, Peter Lieven, 2016/06/21
- Re: [Qemu-devel] Qemu and heavily increased RSS usage, Dr. David Alan Gilbert, 2016/06/21
- Re: [Qemu-devel] Qemu and heavily increased RSS usage, Peter Lieven, 2016/06/21
- Re: [Qemu-devel] Qemu and heavily increased RSS usage, Stefan Hajnoczi, 2016/06/22
- Re: [Qemu-devel] Qemu and heavily increased RSS usage, Peter Lieven, 2016/06/22
- Re: [Qemu-devel] Qemu and heavily increased RSS usage, Peter Maydell, 2016/06/22
- Re: [Qemu-devel] Qemu and heavily increased RSS usage, Stefan Hajnoczi, 2016/06/24
- Re: [Qemu-devel] Qemu and heavily increased RSS usage, Peter Lieven, 2016/06/24
- Re: [Qemu-devel] Qemu and heavily increased RSS usage,
Dr. David Alan Gilbert <=
- Re: [Qemu-devel] Qemu and heavily increased RSS usage, Peter Maydell, 2016/06/24
- Re: [Qemu-devel] Qemu and heavily increased RSS usage, Peter Lieven, 2016/06/24
- Re: [Qemu-devel] Qemu and heavily increased RSS usage, Stefan Hajnoczi, 2016/06/27
- Re: [Qemu-devel] Qemu and heavily increased RSS usage, Peter Lieven, 2016/06/27
Re: [Qemu-devel] Qemu and heavily increased RSS usage, Peter Lieven, 2016/06/23
Re: [Qemu-devel] Qemu and heavily increased RSS usage, Peter Lieven, 2016/06/23
Re: [Qemu-devel] Qemu and heavily increased RSS usage, Paolo Bonzini, 2016/06/23