Automated Windows x64 builds?

[solarmystic]

It seems like it could be beneficial to have it for a certain subset of users like myself.

Background:-

I was having a discussion with daxtsu about potential performance differences between 32bit builds and 64bit builds. We came to a preliminary understanding that it shouldn't make that much of a difference in real world performance, i.e. performance should be within 0-5% for the same build whether compiled in 32 bit or 64 bit when ran in a 64bit environment.

I was curious anyway to see if that understanding would hold up when applied in testing.

The Test:-

Procedure:-

The main procedure adhered to is the one outlined in daxtsu's benchmarking PPSSPP with cube.iso thread:-

http://forums.ppsspp.org/showthread.php?...4#pid26564

All PPSSPP settings are adjusted according to that post.

The candidates:-

I had daxtsu provide me with two of his own compiled builds based on the latest master, (1140), with no additional modifications. One 32 bit build and one 64 bit build was used for this test.

The rig used for testing is as follows:-

Intel Core 2 Duo T9550 @ 2.8 GHz
ATI Mobility Radeon 4670 1 GB GDDR3 @ 843/882 MHz
8 GB DDR3 RAM
Windows 7 Professional SP1 x64

The result:-

Using the provided 32 bit build, the rig averaged 918 VPS in the cube.iso benchmark, as compared to the 1449 VPS obtained using the 64 bit build.

32bit build



64bit build



The findings were well beyond the expected deviation in performance between the 2 builds (0-5%), so the tests were repeated 5 more times to ensure that the figures were not in doubt.

Additional related findings/Possible explanation:-

It seems like using the 64bit build yielded an increased VPS due the fact that the GPU was being completely utilized (leading to 1440 VPS) as compared to the 65-66% GPU utilization (which results in 9xx VPS) when the 32 bit build was used, as observed using GPUz's GPU utilization counter.

I speculate that the use of the 32 bit build brings along with it increased CPU overhead as observed from the Task Manager for this particular set of hardware, which prevents the GPU from working at 100% capacity for the same cube.iso benchmark.

PPSSPP showed 100% utilization of a single core (50% out of two, effectively) for the 32 bit build, meaning it was CPU limited even before the GPU could be fully pushed. The opposite is true for the 64 bit build.

32bit CPU utilization with Unlimited VPS:-



64bit CPU utilization with Unlimited VPS:-




Conclusion:-

It seems that for this one particular user scenario, the use of a 64 bit build brings along with it a tangible increase in performance that could possibly benefit others with similar hardware configurations.