Latency and HPC Workloads

Article: Intel's Near-Threshold Voltage Computing and Applications
By: forestlaughing (forestlaughing.delete@this.yahoo.com), October 15, 2012 8:57 am
Room: Moderated Discussions
> One of the things i
> really don't like in HPC since the whole "clusters take over vector processors"
> has taken place is that even the top machines on top500 are stuck with commodity
> DRAM+hardware managed caches. Everybody is complaining about the memory wall but
> something like RLDRAM-3 (AFAIK) has never been used outside networking
> equipment.
> Disregarding the physical implementation seems that a Cray T90 was a
> much better and balanced architecture for HPC.

The T90 was very balanced, given the state of technology at the time. It's not true that you could scale that architecture up to today, and get that same level of balance, even for $50million/per. T90 was very fast at compute, and had memory bandwidth enough to sustain full triadic operation. The sram memory also had very low latency FOR THAT ERA. A lot of the latency was hidden by vector loads. Scaling that design to today's technology simply doesn't work. There isn't enough space around a device, nor pins on the package to put the hundreds of memory channels on each processor. That technology was very good in an era when a processor filled up an entire board, and memory was on boards several inches away from the processor board.

Cray's successor, the X1 shows the trend away from such a design. Instead of a CPU on a board, it was able to pack a CPU on a multi-chip module, which included 4 high speed cache chips. The rest of the memory was high-bandwidth/high-latency rambus memory, and not enough to support triadic operation without the cache. The X1 was also a numa design, rather than a big flat SMP.

Even custom vector machines have converged into slight variations of what the server processors offer. The advantages of pulling functionality into a single chip are huge. The one thing that can't yet be pulled into the CPU chip, is main memory, at least not in sizes large enough to be super useful. Perhaps chip stacking + TSVs will make this possible.
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TopicPosted ByDate
New article: Intel's Near-Threshold ComputingDavid Kanter2012/09/18 12:26 PM
  Higher SRAM voltage and shared L1Paul A. Clayton2012/09/18 02:38 PM
    Higher SRAM voltage and shared L1David Kanter2012/09/18 05:20 PM
      Higher SRAM voltage and shared L1Eric2012/09/20 10:44 AM
        Higher SRAM voltage and shared L1David Kanter2012/09/20 12:24 PM
      Yes, that kind of asynchronousPaul A. Clayton2012/09/20 02:53 PM
    Higher SRAM voltage and shared L1somebody2012/09/19 09:27 AM
      So micro-turboboost is doubly impracticalPaul A. Clayton2012/09/20 02:53 PM
  Big littleDoug S2012/09/18 03:04 PM
    Big littleDavid Kanter2012/09/18 04:05 PM
    Big littleRicardo B2012/09/19 04:06 AM
  New article: Intel's Near-Threshold Computingdefderdar2012/09/18 09:39 PM
    New article: Intel's Near-Threshold Computingtarlinian2012/09/19 08:32 AM
      New article: Intel's Near-Threshold ComputingDavid Kanter2012/09/19 10:44 AM
  New article: Intel's Near-Threshold ComputingMark Christiansen2012/09/19 11:31 AM
    New article: Intel's Near-Threshold ComputingChris Brodersen2012/09/19 12:54 PM
  New article: Intel's Near-Threshold ComputingEric2012/09/20 10:47 AM
  Latency and HPC WorkloadsRobert Myers2012/10/03 10:52 AM
    Latency and HPC Workloadsanon2012/10/03 06:50 PM
      Latency and HPC WorkloadsRobert Myers2012/10/04 10:24 AM
        Latency and HPC WorkloadsSHK2012/10/08 05:42 AM
          Latency and HPC WorkloadsMichael S2012/10/08 01:59 PM
            Latency and HPC WorkloadsSHK2012/10/08 02:42 PM
              Latency and HPC WorkloadsMichael S2012/10/08 05:12 PM
                Latency and HPC Workloadsforestlaughing2012/10/15 08:41 AM
                  The original context was Micron RLDRAM (NT)Michael S2012/10/15 08:55 AM
                    The original context was Micron RLDRAMforestlaughing2012/10/15 10:21 AM
              Latency and HPC Workloads - Why not SRAM?Kevin G2012/10/09 09:48 AM
                Latency and HPC Workloads - Why not SRAM?Michael S2012/10/09 10:33 AM
                  Latency and HPC Workloads - Why not SRAM?SHK2012/10/09 12:55 PM
                    Why not SRAM? - CapacityRohit2012/10/09 09:13 PM
                  Latency and HPC Workloads - Why not SRAM?Kevin G2012/10/09 03:04 PM
                    Latency and HPC Workloads - Why not SRAM?Michael S2012/10/09 04:52 PM
                      Latency and HPC Workloads - Why not SRAM?Robert Myers2012/10/10 10:11 AM
                        Latency and HPC Workloads - Why not SRAM?forestlaughing2012/10/15 08:02 AM
                          Latency and HPC Workloads - Why not SRAM?Robert Myers2012/10/15 09:04 AM
                            Latency and HPC Workloads - Why not SRAM?forestlaughing2012/10/16 09:13 AM
                          Latency and HPC Workloads - Why not SRAM?SHK2012/10/16 08:12 AM
                    Latency and HPC Workloads - Why not SRAM?slacker2012/10/11 01:35 PM
                      SRAM leakageDavid Kanter2012/10/11 03:00 PM
          Latency and HPC Workloadsforestlaughing2012/10/15 08:57 AM
            Latency and HPC WorkloadsRobert Myers2012/10/16 07:28 AM
              Latency and HPC WorkloadsMichael S2012/10/16 07:35 AM
              Latency and HPC Workloadsanon2012/10/16 08:17 AM
                Latency and HPC WorkloadsRobert Myers2012/10/16 09:56 AM
                  Supercomputer variant of Kahan quotePaul A. Clayton2012/10/16 11:09 AM
                    Supercomputer variant of Kahan quoteanon2012/10/17 01:17 AM
                      Supercomputer variant of Kahan quoteRobert Myers2012/10/17 04:34 AM
                        Supercomputer variant of Kahan quoteanon2012/10/17 05:12 AM
                          Supercomputer variant of Kahan quoteRobert Myers2012/10/17 02:38 PM
                            Supercomputer variant of Kahan quoteanon2012/10/17 05:24 PM
                              Supercomputer variant of Kahan quoteRobert Myers2012/10/17 05:45 PM
                                Supercomputer variant of Kahan quoteanon2012/10/17 05:58 PM
                                Supercomputer variant of Kahan quoteanon2012/10/17 05:58 PM
                                  Supercomputer variant of Kahan quoteRobert Myers2012/10/17 07:14 PM
                                    Supercomputer variant of Kahan quoteanon2012/10/17 08:36 PM
                                      Supercomputer variant of Kahan quoteRobert Myers2012/10/18 09:47 AM
                                        Supercomputer variant of Kahan quoteanon2012/10/19 02:34 AM
                                          Supercomputer variant of Kahan quoteanon2012/10/19 04:47 AM
                                          Supercomputer variant of Kahan quoteRobert Myers2012/10/19 03:14 PM
                        Supercomputer variant of Kahan quoteMichael S2012/10/17 06:56 PM
                          Supercomputer variant of Kahan quoteanon2012/10/17 09:02 PM
                            Supercomputer variant of Kahan quoteRobert Myers2012/10/18 01:29 PM
                              Supercomputer variant of Kahan quoteanon2012/10/19 02:27 AM
                                Supercomputer variant of Kahan quoteRobert Myers2012/10/19 07:24 AM
                                  Supercomputer variant of Kahan quoteanon2012/10/19 08:00 AM
                                    Supercomputer variant of Kahan quoteRobert Myers2012/10/19 09:28 AM
                                      Supercomputer variant of Kahan quoteanon2012/10/19 10:27 AM
                              Supercomputer variant of Kahan quoteforestlaughing2012/10/19 10:26 AM
                                Supercomputer variant of Kahan quoteRobert Myers2012/10/19 07:04 PM
                                  Supercomputer variant of Kahan quoteEmil Briggs2012/10/20 04:52 AM
                                    Supercomputer variant of Kahan quoteRobert Myers2012/10/20 07:51 AM
                                      Supercomputer variant of Kahan quoteEmil Briggs2012/10/20 08:33 AM
                                        Supercomputer variant of Kahan quoteEmil Briggs2012/10/20 08:34 AM
                                          Supercomputer variant of Kahan quoteRobert Myers2012/10/20 09:35 AM
                                            Supercomputer variant of Kahan quoteEmil Briggs2012/10/20 10:04 AM
                                              Supercomputer variant of Kahan quoteRobert Myers2012/10/20 11:23 AM
                  Latency and HPC Workloadsanon2012/10/16 06:48 PM
                    Latency and HPC Workloadsforestlaughing2012/10/19 11:43 AM
              Latency and HPC Workloadsforestlaughing2012/10/19 09:38 AM
                Latency and HPC WorkloadsRobert Myers2012/10/19 11:40 AM
                Potential false economics in researchPaul A. Clayton2012/10/19 12:54 PM
                  Potential false economics in researchVincent Diepeveen2012/10/20 08:59 AM
                  Potential false economics in researchforestlaughing2012/10/23 10:56 AM
                    Potential false economics in researchRobert Myers2012/10/23 07:16 PM
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