Re: disappointing CUDA speed
- To: mathgroup at smc.vnet.net
- Subject: [mg114180] Re: disappointing CUDA speed
- From: Crni Gorac <cgorac at gmail.com>
- Date: Fri, 26 Nov 2010 05:28:49 -0500 (EST)
- References: <iclfde$l9u$1@smc.vnet.net>
On Nov 25, 11:56 am, Gianluca Gorni <gianluca.go... at fastwebnet.it>
wrote:
> Hi,
>
> I have a 1 year old Apple MacBookPro. I installed
> the cudadriver_3.1.17_macos and then tried the first
> examples in the documentation:
>
> Needs["CUDALink`"]
> CUDAQ[]
> True
> randM = RandomReal[1, {3000, 3000}];
> AbsoluteTiming[randM.randM;]
> {2.688389,Null}
>
> AbsoluteTiming[CUDADot[randM, randM];]
> {7.328353,Null}
>
> Quite a letdown.
> Did I do something wrong?
You may wish to re-run CUDADot[] command - there is kind of "warm-up"
needed for CUDA. Also, you may wish to try the next example from
CUDALink user guide, with copying matrix to GPU memory and running
CUDADot[] on it separated - this way, you'll be able to check the
timing for the kernel execution only, which should be better
indication of actual CUDA speed. But overall: I tried the same
examples on alike kind of hardware (CUDA Capability 1.1 generation),
and indeed seems that timings are inconsistent, and also less than
impressive when compared to CUBLAS results. So it'll probably take
some time until eventual bugs of this initial CUDALink release
fixed...