Re: [XTF PATCH] xtf-runner: fix two synchronisation issues

[Wei Liu <wei.liu2@citrix.com>]

On Fri, Jul 29, 2016 at 02:06:56PM +0100, Andrew Cooper wrote:
> On 29/07/16 13:58, Wei Liu wrote:
> > On Fri, Jul 29, 2016 at 01:43:42PM +0100, Andrew Cooper wrote:
> >> On 29/07/16 13:07, Wei Liu wrote:
> >>> There were two synchronisation issues for the old code:
> >>>
> >>> 1. There was no guarantee that guest console was ready before "xl
> >>>    console" invocation.
> >>> 2. There was no guarantee that runner wouldn't not exit before all test
> > s/not//
> >
> >>>    guests were gone.
> >> Sorry, but I can't parse this.
> >>
> >> The runner existing before xl has torn down the guest is very
> >> deliberate, because some part of hvm guests is terribly slow to tear
> >> down; waiting synchronously for teardown tripled the wallclock time to
> >> run a load of tests back-to-back.
> >>
> > Then you won't know if a guest is leaked or it is being slowly destroyed
> > when a dead guest shows up in the snapshot of 'xl list'.
> >
> > Also consider that would make back-to-back tests that happen to have a
> > guest that has the same name as the one in previous test fail.
> 
> test names are globally unique, so this isn't an issue.
> 
> Also, the wait for `xl console` to complete shows that @releasedomain
> has been fired for the domain.
> 

Are you suggesting waiting for "xl console" only is good enough?

> >
> > I don't think getting blocked for a few more seconds is a big issue.
> > It's is important to eliminate such race conditions so that osstest can
> > work properly.
> 
> Amortising the teardown cost in the background is fine (which is what
> your "for child in wait_list" ends up doing), but an extra few seconds
> per test is very important to be avoided for manual use of XTF.
> 

So let's default to not wait and add an option to wait. Osstest will use
that option.

Wei.

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