[Lldb-commits] [lldb] 680082a - [lldb/Reproducers] Add a small artificial delay before exiting

[Jonas Devlieghere via lldb-commits]

On Thu, Apr 9, 2020 at 11:39 AM Davide Italiano <ditaliano at apple.com> wrote:

>
>
> > On Apr 9, 2020, at 11:05, Jonas Devlieghere via lldb-commits <
> lldb-commits at lists.llvm.org> wrote:
> >
> >
> > Author: Jonas Devlieghere
> > Date: 2020-04-09T11:03:24-07:00
> > New Revision: 680082a408dd2df7410d77696100eac8ce9d5530
> >
> > URL:
> https://github.com/llvm/llvm-project/commit/680082a408dd2df7410d77696100eac8ce9d5530
> > DIFF:
> https://github.com/llvm/llvm-project/commit/680082a408dd2df7410d77696100eac8ce9d5530.diff
> >
> > LOG: [lldb/Reproducers] Add a small artificial delay before exiting
> >
> > Add a small artificial delay in replay mode before exiting to ensure
> > that all asynchronous events have completed. This should reduce the
> > level of replay flakiness on some of the slower bots.
> >
> > Added:
> >
> >
> > Modified:
> >    lldb/source/Utility/ReproducerInstrumentation.cpp
> >
> > Removed:
> >
> >
> >
> >
> ################################################################################
> > diff  --git a/lldb/source/Utility/ReproducerInstrumentation.cpp
> b/lldb/source/Utility/ReproducerInstrumentation.cpp
> > index 4c32d9407830..3bf81286bbe9 100644
> > --- a/lldb/source/Utility/ReproducerInstrumentation.cpp
> > +++ b/lldb/source/Utility/ReproducerInstrumentation.cpp
> > @@ -8,6 +8,7 @@
> >
> > #include "lldb/Utility/ReproducerInstrumentation.h"
> > #include "lldb/Utility/Reproducer.h"
> > +#include <thread>
> > #include <stdio.h>
> > #include <stdlib.h>
> >
> > @@ -94,6 +95,10 @@ bool Registry::Replay(llvm::StringRef buffer) {
> >     GetReplayer(id)->operator()(deserializer);
> >   }
> >
> > +  // Add a small artificial delay to ensure that all asynchronous
> events have
> > +  // completed before we exit.
> > +  std::this_thread::sleep_for (std::chrono::milliseconds(100));
> > +
> >   return true;
> > }
> >
>
> I understand this is (unfortunately) sorely needed, but I’m somehow
> skeptical of random delays.
> You probably thought about this and dropped the idea on the floor — but,
> is there a way to make the sync more explicit?
> If you can’t, at least you can detect not everything is in order and
> sleep, for, e.g. another 100 milliseconds in a retry-loop?
>

Yeah, it's a hack, and I'm not really happy with it. The last replayed API
call can be literaly anything, so you don't know what you might have to
wait for. I can't think of a good way to do the synchronization without
breaking layering/abstractions. The issue on GreenDragon was that we exited
before the stop event came in, and while we could probably synchronize
that, it would be even more ad-hoc than this...


>
> —
> Davide
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