Patches to glretrace to add support for looping arbitrary frames
Jon Ashburn
jon at lunarg.com
Tue Apr 22 11:53:08 PDT 2014
glretrace has ability to loop the last frame of a trace continuosly. These
two patches improve upon this feature in several ways. For analysis of
the driver/GPU performance from a captured trace the existing looping can be
improved. Firstly, statistics of the looping performance should be logged,
in addition to the total retrace statistics which include non looping frames.
Secondly, the looping should be generalized for N iterations and any arbitrary
range of frames or API call numbers. Thirdly, time spent in apitrace parsing
and executing calls should be minimized so any driver or GPU bottlenecks are
not masked by glretrace looping replay time.
To achieve these improvements, these features are added to glretrace by these
patches:
Add a numeric parameter to the --loop option which is the number of times to
loop. Zero is continuous looping, default is 1.
Add --framerange option that allows an arbitray range of frames to be looped
and log the time spent in the framerange looping.
Add --callrange option that allows an arbitrary range of call numbers to be
looped and log the time spent in the callrange looping. Framerange and callrange
are mutually exclusive options. --loop=N specifies the number of times to loop
the range. The replay ends after the looping is finished.
When executing a looping replay (non-continuos and iterations != 1) first
save the parsed API calls. Thus, no need to reparse the calls on every
iteration of a loop. This vastly improves the execution time of glretrace.
The looping replay performance, in many cases now matches the performance for
the frames of interest from the original app/benchmark prior to capture. This
makes glretrace a very useful performance analysis tool and also performance
regression tool.
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