Latency and HPC Workloads

Article: Intel's Near-Threshold Voltage Computing and Applications
By: SHK (nomail.delete@this.mail.com), October 8, 2012 2:42 pm
Room: Moderated Discussions
[snip]

First, you will have to convince Intel/AMD to include
support for RLDRAM into their IMCs. According to my understanding, RLDRAM access
protocol is substantially different from SDRAM DDR2/DDR3, or any SDRAM for that
matter, so the required effort is not trivial.


Sure, but i was talking about the higher end of the performance scale, not commodity systems. Something like the big POWER systems, BlueGene or a vector system like the NEC's SX-series. IIRC the SX-6 was available either in a "high capacity" DRAM version or "low latency" FCRAM main memory. Dunno if SX-9 or future NEC systems will have the same config option.


Second, RLDRAM would be pretty
bad for capacity, except if your opt for some form of fully buffered, which by
itself adds more latency than RLDRAM saves.
If I am not mistaken, with RLDRAM you can't currently get more than 512 MB per 64bit "channel". That's like going almost full decade back. With standard unbuffered DDR3 you can easily get 8 GB per channel, with registered DDR3 - up to 96 GB/channel.


On micron.com RLDRAM3 is marked as 576Mbit density vs 8Gbit of commodity DDR3 which is kinda disappointing.
Is the tradeoff capacity vs latency inevitabile like in caches?
Maybe switching to a FLASH+RLDRAM (o similar) would be a better compromise?

I'm asking because i remember papers from more than 10 years ago on the "memory and power wall" but,
while there have been a lot of power efficency improvements, the memory wall keeps getting worse,
and larger caches, prefetch and all that (IMHO!) seems only a palliative solution to the fundamental
problem of redesigning a more balanced memory-ALU interconnection.
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TopicPosted ByDate
New article: Intel's Near-Threshold ComputingDavid Kanter09/18/12 12:26 PM
  Higher SRAM voltage and shared L1Paul A. Clayton09/18/12 02:38 PM
    Higher SRAM voltage and shared L1David Kanter09/18/12 05:20 PM
      Higher SRAM voltage and shared L1Eric09/20/12 10:44 AM
        Higher SRAM voltage and shared L1David Kanter09/20/12 12:24 PM
      Yes, that kind of asynchronousPaul A. Clayton09/20/12 02:53 PM
    Higher SRAM voltage and shared L1somebody09/19/12 09:27 AM
      So micro-turboboost is doubly impracticalPaul A. Clayton09/20/12 02:53 PM
  Big littleDoug S09/18/12 03:04 PM
    Big littleDavid Kanter09/18/12 04:05 PM
    Big littleRicardo B09/19/12 04:06 AM
  New article: Intel's Near-Threshold Computingdefderdar09/18/12 09:39 PM
    New article: Intel's Near-Threshold Computingtarlinian09/19/12 08:32 AM
      New article: Intel's Near-Threshold ComputingDavid Kanter09/19/12 10:44 AM
  New article: Intel's Near-Threshold ComputingMark Christiansen09/19/12 11:31 AM
    New article: Intel's Near-Threshold ComputingChris Brodersen09/19/12 12:54 PM
  New article: Intel's Near-Threshold ComputingEric09/20/12 10:47 AM
  Latency and HPC WorkloadsRobert Myers10/03/12 10:52 AM
    Latency and HPC Workloadsanon10/03/12 06:50 PM
      Latency and HPC WorkloadsRobert Myers10/04/12 10:24 AM
        Latency and HPC WorkloadsSHK10/08/12 05:42 AM
          Latency and HPC WorkloadsMichael S10/08/12 01:59 PM
            Latency and HPC WorkloadsSHK10/08/12 02:42 PM
              Latency and HPC WorkloadsMichael S10/08/12 05:12 PM
                Latency and HPC Workloadsforestlaughing10/15/12 08:41 AM
                  The original context was Micron RLDRAM (NT)Michael S10/15/12 08:55 AM
                    The original context was Micron RLDRAMforestlaughing10/15/12 10:21 AM
              Latency and HPC Workloads - Why not SRAM?Kevin G10/09/12 09:48 AM
                Latency and HPC Workloads - Why not SRAM?Michael S10/09/12 10:33 AM
                  Latency and HPC Workloads - Why not SRAM?SHK10/09/12 12:55 PM
                    Why not SRAM? - CapacityRohit10/09/12 09:13 PM
                  Latency and HPC Workloads - Why not SRAM?Kevin G10/09/12 03:04 PM
                    Latency and HPC Workloads - Why not SRAM?Michael S10/09/12 04:52 PM
                      Latency and HPC Workloads - Why not SRAM?Robert Myers10/10/12 10:11 AM
                        Latency and HPC Workloads - Why not SRAM?forestlaughing10/15/12 08:02 AM
                          Latency and HPC Workloads - Why not SRAM?Robert Myers10/15/12 09:04 AM
                            Latency and HPC Workloads - Why not SRAM?forestlaughing10/16/12 09:13 AM
                          Latency and HPC Workloads - Why not SRAM?SHK10/16/12 08:12 AM
                    Latency and HPC Workloads - Why not SRAM?slacker10/11/12 01:35 PM
                      SRAM leakageDavid Kanter10/11/12 03:00 PM
          Latency and HPC Workloadsforestlaughing10/15/12 08:57 AM
            Latency and HPC WorkloadsRobert Myers10/16/12 07:28 AM
              Latency and HPC WorkloadsMichael S10/16/12 07:35 AM
              Latency and HPC Workloadsanon10/16/12 08:17 AM
                Latency and HPC WorkloadsRobert Myers10/16/12 09:56 AM
                  Supercomputer variant of Kahan quotePaul A. Clayton10/16/12 11:09 AM
                    Supercomputer variant of Kahan quoteanon10/17/12 01:17 AM
                      Supercomputer variant of Kahan quoteRobert Myers10/17/12 04:34 AM
                        Supercomputer variant of Kahan quoteanon10/17/12 05:12 AM
                          Supercomputer variant of Kahan quoteRobert Myers10/17/12 02:38 PM
                            Supercomputer variant of Kahan quoteanon10/17/12 05:24 PM
                              Supercomputer variant of Kahan quoteRobert Myers10/17/12 05:45 PM
                                Supercomputer variant of Kahan quoteanon10/17/12 05:58 PM
                                Supercomputer variant of Kahan quoteanon10/17/12 05:58 PM
                                  Supercomputer variant of Kahan quoteRobert Myers10/17/12 07:14 PM
                                    Supercomputer variant of Kahan quoteanon10/17/12 08:36 PM
                                      Supercomputer variant of Kahan quoteRobert Myers10/18/12 09:47 AM
                                        Supercomputer variant of Kahan quoteanon10/19/12 02:34 AM
                                          Supercomputer variant of Kahan quoteanon10/19/12 04:47 AM
                                          Supercomputer variant of Kahan quoteRobert Myers10/19/12 03:14 PM
                        Supercomputer variant of Kahan quoteMichael S10/17/12 06:56 PM
                          Supercomputer variant of Kahan quoteanon10/17/12 09:02 PM
                            Supercomputer variant of Kahan quoteRobert Myers10/18/12 01:29 PM
                              Supercomputer variant of Kahan quoteanon10/19/12 02:27 AM
                                Supercomputer variant of Kahan quoteRobert Myers10/19/12 07:24 AM
                                  Supercomputer variant of Kahan quoteanon10/19/12 08:00 AM
                                    Supercomputer variant of Kahan quoteRobert Myers10/19/12 09:28 AM
                                      Supercomputer variant of Kahan quoteanon10/19/12 10:27 AM
                              Supercomputer variant of Kahan quoteforestlaughing10/19/12 10:26 AM
                                Supercomputer variant of Kahan quoteRobert Myers10/19/12 07:04 PM
                                  Supercomputer variant of Kahan quoteEmil Briggs10/20/12 04:52 AM
                                    Supercomputer variant of Kahan quoteRobert Myers10/20/12 07:51 AM
                                      Supercomputer variant of Kahan quoteEmil Briggs10/20/12 08:33 AM
                                        Supercomputer variant of Kahan quoteEmil Briggs10/20/12 08:34 AM
                                          Supercomputer variant of Kahan quoteRobert Myers10/20/12 09:35 AM
                                            Supercomputer variant of Kahan quoteEmil Briggs10/20/12 10:04 AM
                                              Supercomputer variant of Kahan quoteRobert Myers10/20/12 11:23 AM
                  Latency and HPC Workloadsanon10/16/12 06:48 PM
                    Latency and HPC Workloadsforestlaughing10/19/12 11:43 AM
              Latency and HPC Workloadsforestlaughing10/19/12 09:38 AM
                Latency and HPC WorkloadsRobert Myers10/19/12 11:40 AM
                Potential false economics in researchPaul A. Clayton10/19/12 12:54 PM
                  Potential false economics in researchVincent Diepeveen10/20/12 08:59 AM
                  Potential false economics in researchforestlaughing10/23/12 10:56 AM
                    Potential false economics in researchRobert Myers10/23/12 07:16 PM
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