[isabelle-dev] sporadic failures of AFP tests

[Gerwin Klein]

On 13/12/2010, at 9:03 PM, Florian Haftmann wrote:

> Am 13.12.2010 10:38, schrieb Tobias Nipkow:
>> Are you referring to
>> 
>> *** Failed to prepare dependency graph
> 
> I remember this also occured, but I am more concerned about the infamous
> error 137 and similar.  Btw. we sometimes have the situation that during
> testing somehow things on NFS seem to disappear, and this might explain
> the error above.  Maybe its best to await the next AFP isatest report
> and then classify the errors systematically.

The logs in ~isatest/afp-log should provide history. 

I think we have a variety of problems:

- NFS flukes
- polyml concurrency heisenbugs
- this very strange "failed to prepare dependency graph"

The last one seemed to be because epstopdf was missing/not found. Whenever I tried to test manually, everything worked, though, and then the error disappeared altogether. Now it seems back again.

We've always had NFS flukes. Not sure why and I gave up trying to track them down with the sysadmins about 6 years ago. Might be time for another try (might be related to above), but not me..

The concurrency heisenbugs are even harder. They are rare and I have never been able to reproduce things reliably. The bigger the session and the more threads used the more likely they seem to occur, but the less useful any kind of bug report will be.

Cheers,
Gerwin