Dear R-mac Users: I'm wanting to leverage an 8-core Intel Mac Pro for all of its computational glory. Looking over the mail list, it appears that the conversation on 64-bit builds of R has been about gaining access to memory beyond the 32-bit limit of 3.5 GB and not about multiple processors/cores. Does running 64-bit R only take advantage of one processor core at a time like the standard 32-bit R, or does it do symmetric multiprocessing (is this the right terminology?). If no, is there any possibility of doing this using X-grid or otherwise that someone can detail? I do have 10.5 Server if I have to go down that road. Thanks, John -- John C. Tull, Ph.D. Conservation Director Nevada Wilderness Project 8550 White Fir Street Reno, NV 89523 USA 775.746.7851 (office) 775.224.2947 (mobile) www.wildnevada.org
Does 64-bit R use multiple cores?
5 messages · Kasper Daniel Hansen, Simon Urbanek, John C. Tull
It depends on the computations you want to do. R for Mac OS X uses Altivec which is a multithreaded version of BLAS and lapack. What this means is that for any computations involving matrix algebra, you do utilize multiple cores. Depending on what you are trying to compute and how that computation is implemented, this may prove to be just what you want or it may have little to no effect. Kasper
On Nov 25, 2008, at 15:24 , John C. Tull wrote:
Dear R-mac Users: I'm wanting to leverage an 8-core Intel Mac Pro for all of its computational glory. Looking over the mail list, it appears that the conversation on 64-bit builds of R has been about gaining access to memory beyond the 32-bit limit of 3.5 GB and not about multiple processors/cores. Does running 64-bit R only take advantage of one processor core at a time like the standard 32-bit R, or does it do symmetric multiprocessing (is this the right terminology?). If no, is there any possibility of doing this using X-grid or otherwise that someone can detail? I do have 10.5 Server if I have to go down that road. Thanks, John -- John C. Tull, Ph.D. Conservation Director Nevada Wilderness Project 8550 White Fir Street Reno, NV 89523 USA 775.746.7851 (office) 775.224.2947 (mobile) www.wildnevada.org
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I thought Altivec was a ppc-only optimization. I'm pretty sure this does not apply to Intel systems, but maybe I'm wrong. John
On Nov 24, 2008, at 10:23 PM, Kasper Daniel Hansen wrote:
It depends on the computations you want to do. R for Mac OS X uses Altivec which is a multithreaded version of BLAS and lapack. What this means is that for any computations involving matrix algebra, you do utilize multiple cores. Depending on what you are trying to compute and how that computation is implemented, this may prove to be just what you want or it may have little to no effect. Kasper On Nov 25, 2008, at 15:24 , John C. Tull wrote:
Dear R-mac Users: I'm wanting to leverage an 8-core Intel Mac Pro for all of its computational glory. Looking over the mail list, it appears that the conversation on 64-bit builds of R has been about gaining access to memory beyond the 32-bit limit of 3.5 GB and not about multiple processors/cores. Does running 64-bit R only take advantage of one processor core at a time like the standard 32-bit R, or does it do symmetric multiprocessing (is this the right terminology?). If no, is there any possibility of doing this using X-grid or otherwise that someone can detail? I do have 10.5 Server if I have to go down that road. Thanks, John -- John C. Tull, Ph.D. Conservation Director Nevada Wilderness Project 8550 White Fir Street Reno, NV 89523 USA 775.746.7851 (office) 775.224.2947 (mobile) www.wildnevada.org
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On Nov 25, 2008, at 11:28 , John C. Tull wrote:
I thought Altivec was a ppc-only optimization. I'm pretty sure this does not apply to Intel systems, but maybe I'm wrong.
The Altivec part was incorrect but the multithreaded BLAS part was correct. Replace Altivec with your favorite three-letter code for Intel CPUs ;). [Not that Altivec matters in any way, since it supports spfp only which R doesn't use ...]. For more parallelization, see snow and pnmath by Luke Tierney. Cheers, S
On Nov 24, 2008, at 10:23 PM, Kasper Daniel Hansen wrote:
It depends on the computations you want to do. R for Mac OS X uses Altivec which is a multithreaded version of BLAS and lapack. What this means is that for any computations involving matrix algebra, you do utilize multiple cores. Depending on what you are trying to compute and how that computation is implemented, this may prove to be just what you want or it may have little to no effect. Kasper On Nov 25, 2008, at 15:24 , John C. Tull wrote:
Dear R-mac Users: I'm wanting to leverage an 8-core Intel Mac Pro for all of its computational glory. Looking over the mail list, it appears that the conversation on 64-bit builds of R has been about gaining access to memory beyond the 32-bit limit of 3.5 GB and not about multiple processors/cores. Does running 64-bit R only take advantage of one processor core at a time like the standard 32-bit R, or does it do symmetric multiprocessing (is this the right terminology?). If no, is there any possibility of doing this using X-grid or otherwise that someone can detail? I do have 10.5 Server if I have to go down that road. Thanks, John -- John C. Tull, Ph.D. Conservation Director Nevada Wilderness Project 8550 White Fir Street Reno, NV 89523 USA 775.746.7851 (office) 775.224.2947 (mobile) www.wildnevada.org
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Simon, Thanks for this information. Some better googling this morning revealed snow. I will also look into pnmath. Regards, John
On Nov 25, 2008, at 10:17 AM, Simon Urbanek wrote:
On Nov 25, 2008, at 11:28 , John C. Tull wrote:
I thought Altivec was a ppc-only optimization. I'm pretty sure this does not apply to Intel systems, but maybe I'm wrong.
The Altivec part was incorrect but the multithreaded BLAS part was correct. Replace Altivec with your favorite three-letter code for Intel CPUs ;). [Not that Altivec matters in any way, since it supports spfp only which R doesn't use ...]. For more parallelization, see snow and pnmath by Luke Tierney. Cheers, S
On Nov 24, 2008, at 10:23 PM, Kasper Daniel Hansen wrote:
It depends on the computations you want to do. R for Mac OS X uses Altivec which is a multithreaded version of BLAS and lapack. What this means is that for any computations involving matrix algebra, you do utilize multiple cores. Depending on what you are trying to compute and how that computation is implemented, this may prove to be just what you want or it may have little to no effect. Kasper On Nov 25, 2008, at 15:24 , John C. Tull wrote:
Dear R-mac Users: I'm wanting to leverage an 8-core Intel Mac Pro for all of its computational glory. Looking over the mail list, it appears that the conversation on 64-bit builds of R has been about gaining access to memory beyond the 32-bit limit of 3.5 GB and not about multiple processors/cores. Does running 64-bit R only take advantage of one processor core at a time like the standard 32-bit R, or does it do symmetric multiprocessing (is this the right terminology?). If no, is there any possibility of doing this using X-grid or otherwise that someone can detail? I do have 10.5 Server if I have to go down that road. Thanks, John -- John C. Tull, Ph.D. Conservation Director Nevada Wilderness Project 8550 White Fir Street Reno, NV 89523 USA 775.746.7851 (office) 775.224.2947 (mobile) www.wildnevada.org
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