GPU raw H/W only has about a 10x advantage over a CPU

Article: Parallelism at HotPar 2010
By: Richard (no.delete@this.email.com), August 25, 2010 12:03 pm
Room: Moderated Discussions
>Look it's rather trivial, if you want to program some problem onto the GPU that
>you previously did do at the cpu's, then also in my calculations the speedup is
>roughly 5x to 10x, pure theoretic spoken; not practical yet, over a quadcore.

How can you make such a claim, this totally depends on the algorithm at hand. When porting algorithms to the GPU you have to take into account issues such as SIMD width, number of concurrent kernels which can be run, not using too many registers so you run enough 'threads' to hide the latency to main memory, finding an algorithm which can make effective use of local store, having enough IPC (Ati's VLIW) and much more. Ah wait, it is theoretical, are we counting ALUs?

>Yet that advantage
>
>a) is only for AMD, not for nvidia
>
>Nvidia is SLOWER in most gpgpu related tasks.

No, it is not.

>Amazingly all postings i see everywhere are regarding nvidia, ...

There is no conspiracy, Nvidia's development environment is just miles ahead of Ati's.

>... but realize nvidia
>has 240 cores and AMD has 3200 streamcores. That's more like factor 10 more or something.

That makes no sense whatsoever. The number of ALUs says nothing about total performance, those 'number of cores' numbers are just for the marketing guys which try to market ALUs as cores.

GPUs don't really have cores, but rather SIMDs. Fermi has 16 of them, ATI's Evergreen has 20. You can run 16 concurrent kernels on Fermi, but just one on ATi at the moment (the hardware probably supports 4). To make things more complex in Ati's architecture there are 16 wide SIMDs which have 5 wide VLIW per lane, NVIDIA's SIMDs are now also 16 wide (but are exposed as 32 wide) and scalar. Nvidia's SIMDS clock much higher than Ati's do. There is an excellent article by David Kanter on this very site about Fermi, which describes Fermi's architecture in great detail.

>Now of course with many games that run on gpu's, it is the case that this opengl
>and directx simply doesn't parallellize THAT WELL, that it can use the full potential
>of 3200 streamcores; otherwise in every benchmark of course nvidia would lose it bigtime to AMD.

Actually, games can use those 'cores' really well. That is why ATI's architecture does so well.

>Yet in gpgpu, you CAN use all those streamcores very nice, if you do big effort.

No, effort will not help you if your algorithm is not portable to a SIMD architecture. Furthermore, on ATI the DirectX driver can use the concurrent kernel functions supported by the hardware, while the OpenCL programmers cannot.

>reports are right now 25%-30% IPC at nvidia and 50% at AMD that the gpu programmers achieve for the same application.

Uhm, compared to CPUs? Where did you find such numbers?

Look, in my view, the GPU is not in direct competition with the CPU, it is just that some problems, not most, map really well to the SIMD paradigm and this makes the GPU interesting to use for that subset of problems. Eventually, we'll have CPUs with better SIMDs like Larrabee's SIMD extensions. If OpenCL is supported better at that time that would mean you can run your parallel algorithm on the GPU, CPU or both. CUDA is a nice stop-gap solution in the meantime.
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TopicPosted ByDate
Tarek's Hotpar 2010 article onlineDavid Kanter2010/07/27 07:29 AM
  Tarek's Hotpar 2010 article onlineAnon2010/07/27 01:57 PM
    Tarek's Hotpar 2010 article onlineDavid Kanter2010/07/27 10:48 PM
      Tarek's Hotpar 2010 article onlineAnon2010/07/28 02:44 PM
        Tarek's Hotpar 2010 article onlineanon2010/07/28 04:10 PM
        CPU+GPUDavid Kanter2010/07/29 11:38 AM
          CPU+GPUMark Christiansen2010/07/30 06:36 AM
            CPU+GPUhobold2010/07/30 06:54 AM
              CPU+GPUGabriele Svelto2010/07/30 07:18 AM
                CPU+GPUhobold2010/07/30 02:46 PM
              CPU+GPUAaron Spink2010/08/02 05:32 PM
                CPU+GPUhobold2010/08/03 03:33 AM
                  CPU+GPURicardo B2010/08/03 04:19 AM
            CPU+GPU - the software problemVincent Diepeveen2010/07/31 04:50 PM
              CPU+GPU - the software problemmpx2010/08/02 11:19 AM
                CPU+GPU - the software problemRichard Cownie2010/08/02 12:48 PM
                  CPU+GPU - the software problemGabriele Svelto2010/08/02 11:10 PM
                    CPU+GPU - the software problemhobold2010/08/03 03:41 AM
                      CPU+GPU - the software problemRichard Cownie2010/08/03 05:17 AM
                        CPU+GPU - the software problemhobold2010/08/04 06:45 AM
                          NVidia in a holeRichard Cownie2010/08/04 07:23 AM
                            NVidia in a holeRohit2010/08/04 07:33 AM
                              NVidia in a holeRichard Cownie2010/08/04 07:50 AM
                                NVidia in a holeRohit2010/08/05 06:31 AM
                                  NVidia in a holeGroo2010/08/05 01:08 PM
                                NVidia in a holeGroo2010/08/05 01:07 PM
                              NVidia in a holeMark Roulo2010/08/04 08:26 AM
                                NVidia in a holeLaughabee2010/08/18 07:28 AM
                            Can nVidia survive without a sub-$100 GPU market?Mark Roulo2010/08/04 08:29 AM
                              Can nVidia survive without a sub-$100 GPU market?Richard Cownie2010/08/04 08:42 AM
                                Can nVidia survive without a sub-$100 GPU market?Mark Roulo2010/08/04 08:55 AM
                                  Can nVidia survive without a sub-$100 GPU market?Linus Torvalds2010/08/04 10:35 AM
                                    "profit" is subjectiveRichard Cownie2010/08/04 10:49 AM
                                      "profit" is subjectivea reader2010/08/06 03:54 AM
                                        no price warRichard Cownie2010/08/06 06:18 AM
                                  Can nVidia survive without a sub-$100 GPU market?Aaron Spink2010/08/04 11:19 AM
                                  Can nVidia survive without a sub-$100 GPU market?Konrad Schwarz2010/08/06 07:13 AM
                                CPU lineup != GPU lineupRohit2010/08/05 06:43 AM
                                  CPU lineup != GPU lineupRichard Cownie2010/08/05 07:12 AM
                                    CPU lineup != GPU lineupRohit2010/08/05 07:37 AM
                                      CPU lineup != GPU lineupRichard Cownie2010/08/05 07:56 AM
                                        CPU lineup != GPU lineupRohit2010/08/05 10:19 AM
                                          CPU lineup != GPU lineuphobold2010/08/06 03:08 AM
                                            CPU lineup != GPU lineupRohit2010/08/06 06:24 AM
                                              CPU lineup != GPU lineuphobold2010/08/06 06:41 AM
                              Can nVidia survive without a sub-$100 GPU market?David Hess2010/08/04 10:31 AM
                              Can nVidia survive without a sub-$100 GPU market?Ricardo B2010/08/04 12:16 PM
                              Semiconductor economicsDavid Kanter2010/08/05 08:13 AM
                                Semiconductor economicsRichard Cownie2010/08/05 08:51 AM
                                  NV buying ViA could shake up thingsRohit2010/08/05 10:09 AM
                                    NV buying ViA could shake up thingsRichard Cownie2010/08/05 10:25 AM
                                      Not likelyDavid Kanter2010/08/05 01:39 PM
                                        Not likelyrandom2010/08/05 01:49 PM
                                          Not likelyAaron Spink2010/08/05 02:18 PM
                                        Not likelyGroo2010/08/05 09:05 PM
                                        Not likelyRohit2010/08/06 06:25 AM
                                    NV buying ViA could shake up thingsGroo2010/08/05 09:02 PM
                                    NV buying ViA could shake up thingsehud2010/08/06 12:53 AM
                                      NV buying ViA could shake up thingsRohit2010/08/06 06:30 AM
                                        NV buying ViA could shake up thingsKevin G2010/08/06 04:54 PM
                                          ViA buying NV could shake up thingsBrendan2010/08/19 05:23 AM
                                        NV buying ViA could shake up thingsGroo2010/08/06 07:24 PM
                            NVidia in a holempx2010/08/04 11:01 AM
                              NVidia in a holeRichard Cownie2010/08/04 11:31 AM
                                NVidia in a holercf2010/08/04 02:40 PM
                              NVidia in a holeRohit2010/08/05 06:51 AM
                              NVidia in a holeGroo2010/08/05 08:50 PM
                              NVidia in a holeAaron Spink2010/08/05 10:52 PM
                          Anyone else wish Intel would buy Nvidia ? (NT)Silent2010/08/07 12:30 AM
                            Hell noa2010/08/07 07:37 PM
                        CPU+GPU - the software problemno thanks2010/08/04 06:54 PM
                          CPU+GPU - the software problemJouni Osmala2010/08/05 12:41 AM
                            CPU+GPU - the software problemIntelUser20002010/08/05 06:54 PM
                              CPU+GPU - the software problemJouni Osmala2010/08/05 08:36 PM
                            CPU+GPU - the software problemLinus Torvalds2010/08/06 07:08 AM
                              CPU+GPU - the software problemanonymous2010/08/06 08:39 AM
                                CPU+GPU - the software problemLinus Torvalds2010/08/06 09:56 AM
                                  non-existent Via+NV vs real OntarioRichard Cownie2010/08/06 11:12 AM
                              CPU+GPU - the software problemkoby m.2010/08/07 01:06 AM
                  CPU+GPU - the software problemhobold2010/08/03 03:48 AM
                CPU+GPU - the software problemhobold2010/08/03 03:45 AM
                  CPU+GPU - the software problemRichard Cownie2010/08/03 05:22 AM
          CPU+GPUAnon2010/07/30 08:11 PM
            CPU+GPUanon2010/07/31 02:19 AM
            CPU+GPUAaron Spink2010/08/02 05:45 PM
          100x speedups -- here we go againAM2010/08/02 12:37 AM
            100x speedups -- here we go againanon2010/08/02 02:32 AM
              100x speedups -- here we go againanon2010/08/02 10:14 PM
            GPU raw H/W only has about a 10x advantage over a CPUMark Roulo2010/08/02 08:41 AM
              GPU raw H/W only has about a 10x advantage over a CPUMichael S2010/08/02 02:31 PM
                GPU raw H/W only has about a 10x advantage over a CPUanon2010/08/02 08:36 PM
                  GPU raw H/W only has about a 10x advantage over a CPUMichael S2010/08/02 11:41 PM
                    GPU raw H/W only has about a 10x advantage over a CPUMark Roulo2010/08/03 07:22 AM
                      GPU raw H/W only has about a 10x advantage over a CPURohit2010/08/04 06:08 AM
                      There is reasonable explanation...Jouni Osmala2010/08/04 09:10 PM
                  GPU raw H/W only has about a 10x advantage over a CPUMark Roulo2010/08/03 07:19 AM
              simple reality check for youAM2010/08/03 12:45 AM
                simple reality check for younone2010/08/03 06:27 AM
                  simple reality check for youAM2010/08/03 10:50 PM
                    simple reality check for youanon2010/08/03 11:06 PM
                      simple reality check for youAM2010/08/05 02:51 AM
                        catch the same boat as everyone else next time (NT)anon2010/08/05 03:44 AM
                Simple reality checkDavid Kanter2010/08/03 07:24 AM
                  Simple reality checkGabriele Svelto2010/08/03 09:51 PM
                  Simple reality checkAM2010/08/03 10:57 PM
                    Simple reality checkanon2010/08/03 11:12 PM
                      Simple reality checkAM2010/08/05 02:59 AM
                        Simple reality checkanon2010/08/05 03:47 AM
                          Study the papers, troll (NT)AM2010/08/05 11:01 PM
                    Simple reality checkhobold2010/08/04 04:05 AM
                    Simple reality checkDean Kent2010/08/04 08:30 AM
                      Simple reality checkMark Roulo2010/08/04 08:59 AM
                      Suggestion for David Kanter and Mark RouloAM2010/08/05 02:57 AM
                        Suggestion for David Kanter and Mark Roulonone2010/08/05 03:22 AM
                          Suggestion for David Kanter and Mark RouloAM2010/08/05 11:04 PM
                        Suggestion for David Kanter and Mark Roulonone2010/08/05 03:38 AM
                          Suggestion for David Kanter and Mark Rouloanon2010/08/05 03:43 AM
                            Suggestion for David Kanter and Mark RouloAM2010/08/05 11:11 PM
                              Suggestion for David Kanter and Mark Rouloanon2010/08/06 06:52 AM
                          Suggestion for David Kanter and Mark RouloAM2010/08/05 11:10 PM
                            Suggestion for David Kanter and Mark Roulonone2010/08/06 12:35 AM
                              price doesn't matter only in theories (NT)AM2010/08/09 01:13 AM
                            Not apple4appleMichael S2010/08/06 04:13 AM
                              Not apple4appleAM2010/08/09 01:09 AM
                                Not apple4appleMichael S2010/08/09 03:35 AM
                                  Not apple4appleAM2010/08/10 12:05 AM
                                    Not apple4applenone2010/08/10 12:38 AM
                                      Back to topicAM2010/08/10 11:03 PM
                                      Final note (and some remarks on Intel's paper)AM2010/08/13 03:28 AM
                                        Final note (and some remarks on Intel's paper)none2010/08/13 08:10 AM
                                          Final note (and some remarks on Intel's paper)AM2010/08/16 12:14 AM
                                            Final note (and some remarks on Intel's paper)none2010/08/16 05:29 AM
                                              One example of 1000X shown to be wrong.sea2010/08/16 06:55 PM
                                                You're short of some factsAM2010/08/17 12:13 AM
                                                  Maybe you need to read beyond the PR statementSteve Underwood2010/08/17 01:39 AM
                                                    Maybe you need to read beyond the PR statementGroo2010/08/17 07:18 PM
                                                    check the hw they usedAM2010/08/18 02:33 AM
                                                Please realize what Monte Carlo meansVincent Diepeveen2010/08/18 02:28 AM
                                              Final note (and some remarks on Intel's paper)AM2010/08/17 12:18 AM
                                        Final note (and some remarks on Intel's paper)anon2010/08/14 12:22 AM
                                          Final note (and some remarks on Intel's paper)AM2010/08/16 12:15 AM
                                            Final note (and some remarks on Intel's paper)anon2010/08/16 01:10 PM
                                              Final note (and some remarks on Intel's paper)AM2010/08/17 12:15 AM
                                                Final note (and some remarks on Intel's paper)Michael S2010/08/17 01:58 AM
                                                  Final note (and some remarks on Intel's paper)AM2010/08/18 02:17 AM
                                                    Final note (and some remarks on Intel's paper)gallier22010/08/18 03:52 AM
                                                    Final note (and some remarks on Intel's paper)Michael S2010/08/18 04:33 AM
                                                      Final note (and some remarks on Intel's paper)Gabriele Svelto2010/08/18 05:11 AM
                                                      Final note (and some remarks on Intel's paper)Steve Underwood2010/08/18 03:03 PM
                                                        Intel might be moving from ISA to platformhobold2010/08/19 02:58 AM
                                                          Intel might be moving from ISA to platformSteve Underwood2010/08/22 06:00 PM
                                                            Intel might be moving from ISA to platformAnon2010/08/22 09:43 PM
                                                              Intel might be moving from ISA to platformajensen2010/08/22 11:37 PM
                                                                Intel might be moving from ISA to platformMichael S2010/08/23 01:13 AM
                                                                  Intel might be moving from ISA to platformSteve Underwood2010/08/23 01:35 AM
                                                                  Intel might be moving from ISA to platformhobold2010/08/26 03:37 AM
                                                                Intel might be moving from ISA to platformAnon2010/08/23 02:47 PM
                                                              Intel might be moving from ISA to platformSteve Underwood2010/08/23 01:25 AM
                                                                Intel might be moving from ISA to platformhobold2010/08/23 02:03 AM
                                                                  Intel might be moving from ISA to platformSteve Underwood2010/08/23 03:26 AM
                                                                Intel might be moving from ISA to platformAnon2010/08/23 02:55 PM
                                                                Intel might be moving from ISA to platformrwessel2010/08/23 05:41 PM
                                                                  Intel might be moving from ISA to platformSteve Underwood2010/08/23 06:30 PM
                                                                    Intel might be moving from ISA to platformrwessel2010/08/23 08:50 PM
                                                                      Intel might be moving from ISA to platformSteve Underwood2010/08/23 09:34 PM
                                                                        Intel might be moving from ISA to platformrwessel2010/08/24 12:03 AM
                                                              Intel might be moving from ISA to platformIan Ollmann2010/08/23 08:21 PM
                                                          Intel might be moving from ISA to platformajensen2010/08/22 09:36 PM
                                                            Intel might be moving from ISA to platformIan Ollmann2010/08/23 08:45 PM
                                                      Final note (and some remarks on Intel's paper)AM2010/08/19 12:29 AM
                                                        Final note (and some remarks on Intel's paper)Richard2010/08/19 03:51 AM
                                                          I stand corrected.Michael S2010/08/19 04:30 AM
                simple reality check for youanonymous2010/08/03 09:25 AM
                  simple reality check for youAM2010/08/03 10:47 PM
                    simple reality check for youanonymous2010/08/04 09:17 AM
                      simple reality check for youanon2010/08/04 07:33 PM
                      SPECint/FPAM2010/08/05 02:49 AM
                  simple reality check for youRohit2010/08/13 07:31 PM
                    simple reality check for youhobold2010/08/16 05:29 AM
              maybe texture caches ?Richard Cownie2010/08/03 08:27 AM
                maybe texture caches ?none2010/08/03 08:59 AM
                  maybe texture caches ?Richard Cownie2010/08/03 09:15 AM
                    maybe texture caches ?Mark Roulo2010/08/03 09:23 AM
                      maybe texture caches ?Richard Cownie2010/08/03 09:33 AM
                        maybe texture caches ?Mark Roulo2010/08/03 09:37 AM
                          the Hess paperRichard Cownie2010/08/03 10:16 AM
                    maybe texture caches ?Aaron Spink2010/08/03 12:23 PM
                      maybe texture caches ?Mark Roulo2010/08/03 03:13 PM
                        maybe texture caches ?Michael S2010/08/04 12:47 AM
                  maybe texture caches ?Michael S2010/08/03 09:23 AM
                maybe texture caches ?Mark Roulo2010/08/03 09:19 AM
                  maybe texture caches ?Richard Cownie2010/08/03 09:42 AM
                Cache to cache comparisonDavid Kanter2010/08/03 11:28 AM
                  Cache to cache comparisonRichard Cownie2010/08/03 11:52 AM
                    Cache to cache comparisonDavid Kanter2010/08/03 12:21 PM
                      Cache to cache comparisonRichard Cownie2010/08/03 02:55 PM
                      Cache to cache comparisonGabriele Svelto2010/08/03 10:23 PM
                        Nehalem vs Core2Richard Cownie2010/08/04 03:24 PM
                          Nehalem vs Core2IntelUser20002010/08/04 06:26 PM
                          Nehalem vs Core2Gabriele Svelto2010/08/04 09:51 PM
                            Nehalem vs Core2Richard Cownie2010/08/05 02:27 AM
                              Nehalem vs Core2Gabriele Svelto2010/08/05 05:00 AM
                                Nehalem vs Core2Richard Cownie2010/08/05 06:10 AM
                                  Nehalem vs Core2Gabriele Svelto2010/08/05 06:41 AM
                                    Nehalem vs Core2Michael S2010/08/05 09:02 AM
                              Nehalem vs Core2Michael S2010/08/05 09:12 AM
                          Nehalem vs Core2Michael S2010/08/04 11:36 PM
                            Nehalem vs Core2Richard Cownie2010/08/05 07:33 AM
                              Nehalem vs Core2Michael S2010/08/05 08:44 AM
                                Nehalem vs Core2Richard Cownie2010/08/05 09:03 AM
                                  Nehalem vs Core2Michael S2010/08/05 03:21 PM
                                    Nehalem vs Core2Richard Cownie2010/08/05 06:15 PM
                                      I'm wrong, you're right - i's 2 dieRichard Cownie2010/08/05 06:21 PM
                                    Nehalem vs Core2Richard Cownie2010/08/06 07:12 AM
                                      Nehalem vs Core2Michael S2010/08/06 07:33 AM
                                      Nehalem L1 cache latency a hedge for higher clock speeds?Mark Roulo2010/08/06 07:36 AM
                                        Nehalem L1 cache latency a hedge for higher clock speeds?Kevin G2010/08/07 09:14 AM
                                          Nehalem L1 cache latency a hedge for higher clock speeds?IntelUser20002010/08/07 01:32 PM
                                        Nehalem L1 cache latency a hedge for higher clock speeds?someone2010/08/07 01:35 PM
                          difference between C2D/C2Q chipsetsMichael S2010/08/04 11:57 PM
                          Nehalem core goals ... my takeMark Roulo2010/08/06 06:53 AM
                            Bulldozer single-threadRichard Cownie2010/08/06 03:05 PM
                          Nehalem vs Core2Carlie Coats2010/08/07 07:41 AM
                            scalingMichael S2010/08/07 10:12 AM
                            why X5460?Michael S2010/08/07 10:12 AM
                              why X5460?Carlie Coats2010/08/08 03:34 AM
                                why X5460?Michael S2010/08/08 03:42 AM
                                  Polling/PIO based COMM libraries?Michael S2010/08/08 04:14 AM
                    Cache to cache comparisonAnts Aasma2010/08/04 09:00 AM
                      Cache to cache comparisonRichard Cownie2010/08/04 09:08 AM
                        Cache to cache comparisonAnts Aasma2010/08/04 10:28 AM
                      Cache to cache comparisonMichael S2010/08/04 10:33 AM
                        Cache to cache comparisonMark Roulo2010/08/04 11:29 AM
                          Cache to cache comparisonAnts Aasma2010/08/04 12:10 PM
                            Fermi and G200 instruction latencyMark Roulo2010/08/04 01:10 PM
                              Fermi and G200 instruction latencyAnts Aasma2010/08/04 02:01 PM
                        Cache to cache comparisonAnts Aasma2010/08/04 12:00 PM
                        Register read comparisonDavid Kanter2010/08/05 08:16 AM
                          Register read comparisonGabriele Svelto2010/08/05 10:42 PM
                maybe texture caches ?Aaron Spink2010/08/03 12:17 PM
              GPU raw H/W only has about a 10x advantage over a CPURichard2010/08/09 03:58 AM
                GPU raw H/W only has about a 10x advantage over a CPUnone2010/08/09 04:19 AM
                  GPU raw H/W only has about a 10x advantage over a CPUVincent Diepeveen2010/08/24 06:18 AM
                    Forget it, they won't hear itanon2010/08/24 03:37 PM
                    GPU raw H/W only has about a 10x advantage over a CPURichard2010/08/25 12:03 PM
                This forum supports pre tagMichael S2010/08/09 05:03 AM
    Tarek's Hotpar 2010 article onlineRich Vuduc2010/07/28 09:24 AM
      Tarek's Hotpar 2010 article onlineAnon2010/07/28 03:18 PM
  Low hanging fruitMoritz2011/02/03 11:20 AM
    Low hanging fruitJukka Larja2011/02/06 04:01 AM
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