By: aaron spink (aaronspink.delete@this.notearthlink.net), July 28, 2012 7:05 am
Room: Moderated Discussions
Emil Briggs (me.delete@this.nowherespam.com) on July 28, 2012 6:40 am wrote:
> By ORNL do you mean Oak Ridge National Laboratory? I ask
> since I am a large user at ORNL. Currently only some of the Jaguar/Titan nodes
> are equipped with GPU's but there are enough of them installed to do realistic
> evaluations. For certain workloads (and when properly programmed) they beat
> CPU's pretty handily performance wise. And that data comes from a real world
> application not LINPACK. The section of the code that I adapted for GPU's runs 3
> to 4 times faster than it does on CPU's. It's also possible with this particular
> application to overlap some operations on the CPU and GPU and hide the latency
> of PCI-E data transfers. Obviously not all applications can benefit in the same
> way and it's not easy to do so even when possible but GPU's can offer some very
> nice performance gains in some cases.
>
I'm not denying that there are some workloads and some kernels that have an advantage, I am however saying that it is generally the exception based on data published from both PRACE and ORNL, et al.
BTW, what % of peak are you seeing on the GPUs with your code?
> That being said I do think that the
> cost of moving data across the PCI-E bus and the difficulty of the programming
> model are some real downsides to GPU's. How all that plays out will be
> interesting and I'm looking forward to getting my hands on some Intel MIC
> hardware to see what we can do with it.
>
MIC still has the disadvantage of PCI-E being a limiter but it should have a better programming model overall than GPUs. Hopefully we'll eventually see x32/x40 PCI-E interfaces or dual QPI interfaces. Certainly would be nice if the GPUs/MICs had simple coherent access to memory.
> By ORNL do you mean Oak Ridge National Laboratory? I ask
> since I am a large user at ORNL. Currently only some of the Jaguar/Titan nodes
> are equipped with GPU's but there are enough of them installed to do realistic
> evaluations. For certain workloads (and when properly programmed) they beat
> CPU's pretty handily performance wise. And that data comes from a real world
> application not LINPACK. The section of the code that I adapted for GPU's runs 3
> to 4 times faster than it does on CPU's. It's also possible with this particular
> application to overlap some operations on the CPU and GPU and hide the latency
> of PCI-E data transfers. Obviously not all applications can benefit in the same
> way and it's not easy to do so even when possible but GPU's can offer some very
> nice performance gains in some cases.
>
I'm not denying that there are some workloads and some kernels that have an advantage, I am however saying that it is generally the exception based on data published from both PRACE and ORNL, et al.
BTW, what % of peak are you seeing on the GPUs with your code?
> That being said I do think that the
> cost of moving data across the PCI-E bus and the difficulty of the programming
> model are some real downsides to GPU's. How all that plays out will be
> interesting and I'm looking forward to getting my hands on some Intel MIC
> hardware to see what we can do with it.
>
MIC still has the disadvantage of PCI-E being a limiter but it should have a better programming model overall than GPUs. Hopefully we'll eventually see x32/x40 PCI-E interfaces or dual QPI interfaces. Certainly would be nice if the GPUs/MICs had simple coherent access to memory.
Topic | Posted By | Date |
---|---|---|
New Article: Compute Efficiency 2012 | David Kanter | 2012/07/25 01:37 AM |
New Article: Compute Efficiency 2012 | SHK | 2012/07/25 02:31 AM |
New Article: Compute Efficiency 2012 | David Kanter | 2012/07/25 02:42 AM |
New Article: Compute Efficiency 2012 | none | 2012/07/25 03:18 AM |
New Article: Compute Efficiency 2012 | David Kanter | 2012/07/25 11:25 AM |
GCN (NT) | EBFE | 2012/07/25 03:25 AM |
GCN - TFLOP DP | jp | 2012/08/09 01:58 PM |
GCN - TFLOP DP | David Kanter | 2012/08/09 03:32 PM |
GCN - TFLOP DP | Kevin G | 2012/08/11 05:22 PM |
GCN - TFLOP DP | Eric | 2012/08/09 05:12 PM |
GCN - TFLOP DP | jp | 2012/08/10 01:23 AM |
GCN - TFLOP DP | EBFE | 2012/08/12 08:27 PM |
GCN - TFLOP DP | jp | 2012/08/13 02:02 AM |
GCN - TFLOP DP | EBFE | 2012/08/13 07:45 PM |
GCN - TFLOP DP | jp | 2012/08/14 01:21 AM |
New Article: Compute Efficiency 2012 | Adrian | 2012/07/25 04:39 AM |
New Article: Compute Efficiency 2012 | EBFE | 2012/07/25 09:33 AM |
New Article: Compute Efficiency 2012 | David Kanter | 2012/07/25 11:11 AM |
New Article: Compute Efficiency 2012 | sf | 2012/07/25 06:46 AM |
New Article: Compute Efficiency 2012 | aaron spink | 2012/07/25 09:08 AM |
New Article: Compute Efficiency 2012 | someone | 2012/07/25 10:06 AM |
New Article: Compute Efficiency 2012 | David Kanter | 2012/07/25 11:14 AM |
New Article: Compute Efficiency 2012 | EBFE | 2012/07/26 02:27 AM |
BG/Q | David Kanter | 2012/07/26 09:31 AM |
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VR-ZONE KNC B0 leak, poor number? | Eric | 2012/08/03 07:59 AM |
VR-ZONE KNC B0 leak, poor number? | EBFE | 2012/08/04 06:37 AM |
VR-ZONE KNC B0 leak, poor number? | aaron spink | 2012/08/04 06:51 PM |
Leaks != products | David Kanter | 2012/08/05 03:19 AM |
Leaks != products | EBFE | 2012/08/06 02:49 AM |
VR-ZONE KNC B0 leak, poor number? | Eric | 2012/08/05 10:37 AM |
VR-ZONE KNC B0 leak, poor number? | EBFE | 2012/08/06 03:09 AM |
VR-ZONE KNC B0 leak, poor number? | aaron spink | 2012/08/06 04:33 AM |
VR-ZONE KNC B0 leak, poor number? | jp | 2012/08/07 03:08 AM |
VR-ZONE KNC B0 leak, poor number? | Eric | 2012/08/07 04:58 AM |
VR-ZONE KNC B0 leak, poor number? | jp | 2012/08/07 05:17 AM |
VR-ZONE KNC B0 leak, poor number? | Eric | 2012/08/07 05:22 AM |
VR-ZONE KNC B0 leak, poor number? | anonymou5 | 2012/08/07 09:43 AM |
VR-ZONE KNC B0 leak, poor number? | jp | 2012/08/07 05:23 AM |
VR-ZONE KNC B0 leak, poor number? | aaron spink | 2012/08/07 07:24 AM |
VR-ZONE KNC B0 leak, poor number? | aaron spink | 2012/08/07 07:20 AM |
VR-ZONE KNC B0 leak, poor number? | jp | 2012/08/07 11:22 AM |
VR-ZONE KNC B0 leak, poor number? | EduardoS | 2012/08/07 03:15 PM |
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New Article: Compute Efficiency 2012 | forestlaughing | 2012/07/25 08:51 AM |
New Article: Compute Efficiency 2012 | Eric | 2012/07/27 05:12 AM |
New Article: Compute Efficiency 2012 | hobold | 2012/07/27 11:53 AM |
New Article: Compute Efficiency 2012 | Eric | 2012/07/27 12:51 PM |
New Article: Compute Efficiency 2012 | hobold | 2012/07/27 02:48 PM |
New Article: Compute Efficiency 2012 | Eric | 2012/07/27 03:29 PM |
New Article: Compute Efficiency 2012 | anon | 2012/07/29 02:25 AM |
New Article: Compute Efficiency 2012 | hobold | 2012/07/29 11:53 AM |
Efficiency? No, lack of highly useful features | someone | 2012/07/25 09:58 AM |
Best case for GPUs | David Kanter | 2012/07/25 11:28 AM |
Best case for GPUs | franzliszt | 2012/07/25 01:39 PM |
Best case for GPUs | Chuck | 2012/07/25 08:13 PM |
Best case for GPUs | David Kanter | 2012/07/25 09:45 PM |
Best case for GPUs | Eric | 2012/07/27 05:51 AM |
Silverthorn data point | Michael S | 2012/07/25 02:45 PM |
Silverthorn data point | David Kanter | 2012/07/25 04:06 PM |
New Article: Compute Efficiency 2012 | Unununium | 2012/07/25 05:55 PM |
New Article: Compute Efficiency 2012 | EduardoS | 2012/07/25 08:12 PM |
Ops... I'm wrong... | EduardoS | 2012/07/25 08:14 PM |
New Article: Compute Efficiency 2012 | TacoBell | 2012/07/25 08:36 PM |
New Article: Compute Efficiency 2012 | David Kanter | 2012/07/25 09:49 PM |
New Article: Compute Efficiency 2012 | Michael S | 2012/07/26 02:33 AM |
Line and factor | Moritz | 2012/07/26 01:34 AM |
Line and factor | Peter Boyle | 2012/07/27 07:57 AM |
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Line and factor | EduardoS | 2012/07/27 05:24 PM |
Line and factor | Moritz | 2012/07/28 12:52 PM |
tables | Michael S | 2012/07/26 02:39 AM |
Interlagos L2+L3 | Rana | 2012/07/26 03:13 AM |
Interlagos L2+L3 | Rana | 2012/07/26 03:13 AM |
Interlagos L2+L3 | David Kanter | 2012/07/26 09:21 AM |
SP vs DP & performance metrics | jp | 2012/07/27 07:08 AM |
SP vs DP & performance metrics | Eric | 2012/07/27 07:57 AM |
SP vs DP & performance metrics | jp | 2012/07/27 09:18 AM |
SP vs DP & performance metrics | aaron spink | 2012/07/27 09:36 AM |
SP vs DP & performance metrics | jp | 2012/07/27 09:47 AM |
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"Global" --> system | jp | 2012/07/27 03:55 PM |
"Global" --> system | aaron spink | 2012/07/27 07:33 PM |
"Global" --> system | jp | 2012/07/28 02:00 AM |
"Global" --> system | aaron spink | 2012/07/28 06:54 AM |
"Global" --> system | jp | 2012/07/29 02:12 AM |
"Global" --> system | aaron spink | 2012/07/29 05:03 AM |
"Global" --> system | none | 2012/07/29 09:05 AM |
"Global" --> system | EduardoS | 2012/07/29 10:26 AM |
"Global" --> system | jp | 2012/07/30 02:24 AM |
"Global" --> system | aaron spink | 2012/07/30 03:05 AM |
"Global" --> system | aaron spink | 2012/07/30 03:03 AM |
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SP vs DP & performance metrics | aaron spink | 2012/07/27 07:25 PM |
SP vs DP & performance metrics | Emil Briggs | 2012/07/28 06:40 AM |
SP vs DP & performance metrics | aaron spink | 2012/07/28 07:05 AM |
SP vs DP & performance metrics | jp | 2012/07/28 11:04 AM |
SP vs DP & performance metrics | Brett | 2012/07/28 03:32 PM |
SP vs DP & performance metrics | Emil Briggs | 2012/07/28 06:11 PM |
SP vs DP & performance metrics | anon | 2012/07/29 02:53 AM |
SP vs DP & performance metrics | aaron spink | 2012/07/29 05:39 AM |
Coherency for discretes | Rohit | 2012/07/29 09:24 AM |
SP vs DP & performance metrics | anon | 2012/07/29 11:09 AM |
SP vs DP & performance metrics | Eric | 2012/07/29 01:08 PM |
SP vs DP & performance metrics | aaron spink | 2012/07/27 09:25 AM |
Regular updates? | Joe | 2012/07/27 09:35 AM |
New Article: Compute Efficiency 2012 | 309 | 2012/07/27 10:34 PM |
New Article: Compute Efficiency 2012 | Ingeneer | 2012/07/30 09:01 AM |
New Article: Compute Efficiency 2012 | David Kanter | 2012/07/30 01:11 PM |
New Article: Compute Efficiency 2012 | Ingeneer | 2012/07/30 08:04 PM |
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Memory power and bandwidth? | Michael S | 2012/08/04 02:36 PM |
Memory power and bandwidth? | Iain McClatchie | 2012/08/06 02:09 PM |
Memory power and bandwidth? | Eric | 2012/08/07 06:28 PM |
Workloads | David Kanter | 2012/08/08 10:49 AM |
Workloads | Eric | 2012/08/09 05:21 PM |
Latency and bandwidth bottlenecks | Paul A. Clayton | 2012/08/08 04:02 PM |
Latency and bandwidth bottlenecks | Eric | 2012/08/09 05:32 PM |
Latency and bandwidth bottlenecks | none | 2012/08/10 06:06 AM |
Latency and bandwidth bottlenecks -> BDP | ajensen | 2012/08/11 03:21 PM |
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NV aims for 1.8+ TFLOPS DP ? | jp | 2012/08/11 01:21 PM |
NV aims for 1.8+ TFLOPS DP ? | David Kanter | 2012/08/11 09:25 PM |
NV aims for 1.8+ TFLOPS DP ? | jp | 2012/08/12 02:45 AM |
NV aims for 1.8+ TFLOPS DP ? | EBFE | 2012/08/12 10:02 PM |
NV aims for 1.8+ TFLOPS DP ? | jp | 2012/08/13 01:54 AM |
NV aims for 1.8+ TFLOPS DP ? | Gabriele Svelto | 2012/08/13 09:16 AM |
NV aims for 1.8+ TFLOPS DP ? | Vincent Diepeveen | 2012/08/14 03:04 AM |
NV aims for 1.8+ TFLOPS DP ? | David Kanter | 2012/08/13 09:50 AM |
NV aims for 1.8+ TFLOPS DP ? | jp | 2012/08/13 11:17 AM |
NV aims for 1.8+ TFLOPS DP ? | EduardoS | 2012/08/13 06:45 AM |