On Tue, Aug 26, 2014 at 8:44 PM, Dylan Baker <[email protected]> wrote: > Sorry it's taken me so long to get back to this (again), work has > dictated slightly different priorities lately. > > On Tuesday, August 19, 2014 05:45:43 PM Ilia Mirkin wrote: > [snip] >> >> No problem. Locking is probably one of the most complicated subjects >> out there :) I'm again looking at the final output in your >> log-refactor branch, not this patch specifically, although it should >> be ~the same. >> >> def _print(self, out): >> """ Shared print method that ensures any bad lines are overwritten >> """ >> # If the new line is shorter than the old one add trailing >> # whitespace >> pad = self._state['lastlength'] - len(out) >> >> with self._LOCK: >> ... use pad ... >> >> So let's say you have (hopefully the ascii art works out... my >> make-fonts-not-retarded-in-gmail plugin appears to have stopped >> working for email composition) >> >> thread 1 thread 2 >> _print >> _print >> pad = ... >> acquire lock >> pad = ... >> use pad >> self._state['lastlength'] = ... >> release lock >> acquire lock >> use pad >> >> Then that would be unfortunate, right? I think that the retrieval of >> self._state['lastlength'] needs to move inside of the lock. That said, >> it appears that _print is only ever called with the lock already >> taken, in which case it shouldn't bother with the lock at all. In >> general, having recursive locks is a sign of laziness, but I think it >> can be forgiven here. But for _print, perhaps you can just assert that >> the lock has already been taken. > > Right, that makes sense. I'll change that. > >> >> Otherwise this (series) LGTM. Perhaps a little over-locked, but... not >> unreasonably so. >> >> Out of curiousity, what is the dry-run time with this patch on >> tests/gpu.py (for example)? That should give a good idea as to the >> overhead of the locking... perhaps compare it to using >> dummy_threading.RLock. > > When I run 'piglit run quick -c -d foo > /dev/null' (I don't want to > measure the difference in console spewing after all), I see about .3 > seconds difference (~4.6 seconds vs ~4.3 seconds) between > threading.RLock and dummy_threading.RLock. > > Does that seem reasonable to you?
That seems very reasonable to me. I just wanted to make sure it wasn't like... a minute :) -ilia _______________________________________________ Piglit mailing list [email protected] http://lists.freedesktop.org/mailman/listinfo/piglit
