[igt-dev] [PATCH i-g-t] runner/resultgen: Provide output when test output is completely empty

[Chris Wilson]

Quoting Petri Latvala (2020-02-19 13:27:58)
> On Wed, Feb 19, 2020 at 01:23:22PM +0000, Chris Wilson wrote:
> > Quoting Petri Latvala (2020-02-19 12:19:40)
> > > If a machine is hard-hanging or otherwise rebooted at the correct
> > > time, intermediary output files get created but nothing ever gets
> > > written to them. That yields results that are completely empty and
> > > hard to categorize or even sometimes detect automatically. Handle this
> > > corner case explicitly with a custom text explaining what might have
> > > happened to prod result analysis towards fixing the real issue instead
> > > of wondering if test result processing is faulty.
> > > 
> > > The race for getting empty files is easier to hit than it seems. The
> > > files get created by the runner before calling exec(), and there's
> > > plenty of time to hit a really hard crash.
> > 
> > Speaking of which, it would not be terrible if igt_runner periodically
> > called sync() everytime it decided there were new logs to preserve.
> > We should also probably remove/reduce the writeback delay.
> 
> 
> Does calling sync() sync more than fsyncdata()?

No manual entry for fsyncdata(), fdatasync()?
sync/fsync includes metadata, fdatasync is just contents, unless
metadata is required for data retrieval.

So for us, there really shouldn't be any difference between fdatasync
and fsync (with the slight exception of last access timestamps).
-Chris