Forum > GPU crunching
[Split] PowerSpectrum Unit Test
Jason G:
Extra drives on order here ... hopefully will be able to find a floppy disk for XP raid driver install before they arrive ::).
If you're able to verify (increased XPDM advantage with the heavily optimised kernels, over stock ~10% advantage between driver models) prior to me getting setup, I'll report the increased XPDM<->WDDM speed discrepancy with highly optimised kernels ... Since they may not have factored as much as 30% performance difference into decisions (related to TCC mode).
Ghost0210:
I've managed to scavenge an old drive from an old machine for this test, so have now got a dual-boot machine for a short time ;)
Just downloading and installing the standard drivers to get a baseline for the test -
Stock results on XP Pro x32 260.99 drivers:
Device: GeForce GTX 465, 1215 MHz clock, 1024 MB memory.
Compute capability 2.0
Compiled with CUDA 3020.
PowerSpectrum+summax Unit test #5
Stock:
PwrSpec< 64> 16.0 GFlops 63.8 GB/s 0.0ulps
SumMax ( 64) 1.4 GFlops 5.8 GB/s
Every ifft average & peak OK
PS+SuMx( 64) 4.4 GFlops 17.7 GB/s
GetPowerSpectrum() choice for Opt1: 256 thrds/block
256 threads: 23.0 GFlops 91.9 GB/s 121.7ulps
Opt1 (PSmod3+SM): 256 thrds/block
256 threads, fftlen 64: (worst case: full summax copy)
6.7 GFlops 27.2 GB/s 121.7ulps
Every ifft average & peak OK
256 threads, fftlen 64: (best case, nothing to update)
8.7 GFlops 35.3 GB/s 121.7ulps
_heinz:
PowerSpectrumxe2011Test5.exe -device 0
Device: GeForce GTX 470, 810 MHz clock, 1248 MB memory.
Compute capability 2.0
Compiled with CUDA 3020.
PowerSpectrum+summax Unit test #5)
Stock:
PwrSpec< 64> 11.9 GFlops 47.6 GB/s 0.0ulps
SumMax ( 64) 0.4 GFlops 1.7 GB/s
Every ifft average & peak OK
PS+SuMx( 64) 1.4 GFlops 5.8 GB/s
GetPowerSpectrum() choice for Opt1: 256 thrds/block
256 threads: 18.5 GFlops 73.8 GB/s 121.7ulps
Opt1 (PSmod3+SM): 256 thrds/block
256 threads, fftlen 64: (worst case: full summax copy)
2.1 GFlops 8.3 GB/s 121.7ulps
Every ifft average & peak OK
256 threads, fftlen 64: (best case, nothing to update)
2.4 GFlops 9.6 GB/s 121.7ulps
PowerSpectrumxe2011Test5.exe -device 1
Device: GeForce GTX 470, 810 MHz clock, 1249 MB memory.
Compute capability 2.0
Compiled with CUDA 3020.
PowerSpectrum+summax Unit test #5)
Stock:
PwrSpec< 64> 11.9 GFlops 47.6 GB/s 0.0ulps
SumMax ( 64) 0.4 GFlops 1.7 GB/s
Every ifft average & peak OK
PS+SuMx( 64) 1.4 GFlops 5.8 GB/s
GetPowerSpectrum() choice for Opt1: 256 thrds/block
256 threads: 18.3 GFlops 73.3 GB/s 121.7ulps
Opt1 (PSmod3+SM): 256 thrds/block
256 threads, fftlen 64: (worst case: full summax copy)
2.1 GFlops 8.4 GB/s 121.7ulps
Every ifft average & peak OK
256 threads, fftlen 64: (best case, nothing to update)
2.4 GFlops 9.6 GB/s 121.7ulps
.
Done
Remark:compiled with XE2011
modify:
something must be changed, last Test5 above shows
11.2 GFlops 45.3 GB/s 121.7ulps
in last line
Jason G:
--- Quote from: _heinz on 04 Dec 2010, 02:18:56 pm ---
something must be changed, last Test5 above shows
11.2 GFlops 45.3 GB/s 121.7ulps
--- End quote ---
Yeah, 11.2 is more like what that card should be doing heinz.
Jason G:
--- Quote from: Ghost on 04 Dec 2010, 02:09:09 pm ---Stock results on XP Pro x32 260.99 drivers:
...
PS+SuMx( 64) 4.4 GFlops 17.7 GB/s
...
256 threads, fftlen 64: (worst case: full summax copy)
6.7 GFlops 27.2 GB/s 121.7ulps
...
256 threads, fftlen 64: (best case, nothing to update)
8.7 GFlops 35.3 GB/s 121.7ulps
--- End quote ---
OK, so far against your previous results (assuming all else equal), we're back to our roughly ~10% performance advantage to XP:
(XP32-Win7x64)/Win7x64
Stock case: (4.4-4.1)/4.1 = ~7.3 % advantage to XP (expected, not too annoying)
Worst case: (6.7-6.0)/6.0 = ~11.7% advantage to XP ( I can *almost* live with that)
Best case: (8.7-8.7)/8.7 = ~0.0% advantage to XP (fine)
So there appears to be a greater advantage to XP with the worst case (lot's of memory transfers), though not as great as feared... Phew! ;D
Since the Memory numbers have more significant digits, and the worst case advantage indicates a memory issue of some sort, I'll compare the throughput figures also:
Stock case: (17.7-16.5)/16.5 = ~7.27% advantage to XP
Worst case: (27.2-24.2)/24.2 = ~12.4% advantage to XP
Best case: (35.3-35.4)/35.4 = ~0.3% advantage to Win7
Tentative analysis based on above: Raw compute speed between the two OS/Driver models is roughly the same ('Best Case has no memory transfer of results), however WDDM's memory paging schemes increase overheads for the worst case by up to ~14.2% on that system ( 1/(1-0.124) ).
So memory transfers will have to be minimised in critical kernels. I can enable a pinned memory optimisation I implemented for integrated GPUs, which might just help the situation. At least we're not looking at the ~30% difference that had me petrified.
Jason
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