[FFmpeg-devel] [PATCH] Fix threaded mpeg*video encoding

[Måns Rullgård]

M?ns Rullg?rd <mans at mansr.com> writes:

> Michael Niedermayer <michaelni at gmx.at> writes:
>
>> On Thu, Jul 01, 2010 at 12:26:25PM +0100, M?ns Rullg?rd wrote:
>>> Michael Niedermayer <michaelni at gmx.at> writes:
>>> 
>>> > On Thu, Jul 01, 2010 at 04:01:24AM +0100, M?ns Rullg?rd wrote:
>>> >> Michael Niedermayer <michaelni at gmx.at> writes:
>>> >> 
>>> >> > On Wed, Jun 30, 2010 at 03:49:34PM +0100, Mans Rullgard wrote:
>>> >> >> This allocates per-thread copies of some buffers which are updated
>>> >> >> concurrently from the encoding threads.
>>> >> >
>>> >> > is this fixing a bug?
>>> >> > if so please elaborate what and where. My guess would be toward
>>> >> > ac_val being the one causing the issues.
>>> >> 
>>> >> The threaded regression tests are failing randomly with pthreads enabled:
>>> >> 
>>> >> http://fate.multimedia.cx/index.php?test_result=66882641
>>> >> http://fate.multimedia.cx/index.php?test_result=66852547
>>> >> http://fate.multimedia.cx/index.php?test_result=66876769
>>> >> 
>>> >> Those are just a few examples.  Valgrind complained about most of
>>> >> those buffers, particularly ac_val and dc_val, and I add a couple
>>> >> since they were written close to the places valgrind identified.  Race
>>> >> detection is never exact.
>>> >
>>> > could you try to just change ac_val and see if this makes the issue
>>> > go away?
>>> > for ac_val i found ff_mpeg4_clean_buffers() as possible reason for the
>>> > race, for the others i am not aware of code that can lead to a race
>>> 
>>> So OK to commit just the ac_val parts and see what happens?
>>
>> ok
>
> Done.  Let's keep an eye on FATE.

We still have some failures:

http://fate.multimedia.cx/index.php?build_record=251859
http://fate.multimedia.cx/index.php?build_record=251951
http://fate.multimedia.cx/index.php?build_record=251969

-- 
M?ns Rullg?rd
mans at mansr.com