Re: [Xen-devel] [PATCH] libxl: Increase device model startup timeout to 1min.

[Ian Campbell <ian.campbell@xxxxxxxxxx>]

On Mon, 2015-06-29 at 15:23 +0100, Anthony PERARD wrote:
> On Fri, Jun 26, 2015 at 05:41:07PM +0100, Ian Campbell wrote:
> > On Fri, 2015-06-26 at 12:57 +0100, Anthony PERARD wrote:
> > > On a busy host, QEMU may take more than 10s to start.
> > 
> > Please show your working here so that in 2 years when we want to know
> > why this value was chosen we don't have to go scrobbling around in the
> > ML archives looking for the data you gathered.
> 
> OK. What about:

I'm afraid none of that really explains why QEMU taking >10s is
reasonable/expected under the circumstances or why 60s is a good choice
now.

Nor does it really answer Ian's question in
<21901.33163.547929.321814@xxxxxxxxxxxxxxxxxxxxxxxx> I think.

Ian.

> 
> While running the whole stack of OpenStack (install via devstack on Ubuntu)
> on a single machine, sometime the device model fail to start on time. When
> this happen, a strace of QEMU shows that it still loading its libraries.
> 
> You can find such strace on:
> http://lists.xenproject.org/archives/html/xen-devel/2015-06/msg03549.html
> 
> What shows the strace is that between a mmap() syscall and the next
> syscall, 0.5s might have pass.
> 
> Normaly, on this same machine it takes 0.32 second on average for QEMU to
> start, while running Tempest (which is the OpenStack test suite). Those
> QEMU are runned as backend for a PV guest.
> 
> > > 
> > > Signed-off-by: Anthony PERARD <anthony.perard@xxxxxxxxxx>
> > > ---
> > >  tools/libxl/libxl_internal.h | 2 +-
> > >  1 file changed, 1 insertion(+), 1 deletion(-)
> > > 
> > > diff --git a/tools/libxl/libxl_internal.h b/tools/libxl/libxl_internal.h
> > > index e96d6b5..3a604f7 100644
> > > --- a/tools/libxl/libxl_internal.h
> > > +++ b/tools/libxl/libxl_internal.h
> > > @@ -85,7 +85,7 @@
> > >  #define LIBXL_INIT_TIMEOUT 10
> > >  #define LIBXL_DESTROY_TIMEOUT 10
> > >  #define LIBXL_HOTPLUG_TIMEOUT 10
> > > -#define LIBXL_DEVICE_MODEL_START_TIMEOUT 10
> > > +#define LIBXL_DEVICE_MODEL_START_TIMEOUT 60
> > >  #define LIBXL_STUBDOM_START_TIMEOUT 30
> > >  #define LIBXL_QEMU_BODGE_TIMEOUT 2
> > >  #define LIBXL_XENCONSOLE_LIMIT 1048576
> > 
> > 
> 



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