Occam's razor

Article: Knights Landing Details
By: Nicolas Capens (nicolas.capens.delete@this.gmail.com), January 9, 2014 3:07 am
Room: Moderated Discussions
David Kanter (dkanter.delete@this.realworldtech.com) on January 8, 2014 4:53 pm wrote:
> Gabriele Svelto (gabriele.svelto.delete@this.gmail.com) on January 8, 2014 2:51 pm wrote:
> > Nicolas Capens (nicolas.capens.delete@this.gmail.com) on January 8, 2014 2:33 pm wrote:
> > > Occam's razor is about making the fewest assumptions. You're making two assumptions:
> > > 1) The L0 cache is very complex.
> > > 2) The Intel compiler is stupid.
> > >
> > > Firstly an L0 cache isn't complex. Only a few entries are needed and there's only ~20 bits worth of address
> > > encoding to test for a match (http://www.realworldtech.com/forum/?threadid=138897&curpostid=139072).
> >
> > An extra cache layer which must be coherent with another with 72 cores isn't complex and requires
> > only ~20 bits worth of address? Seriously? With no other processor ever implementing anything
> > even remotely similar? It's existence sounds like a HUGE assumption to make considering there's
> > not even the slightest hint of it anywhere (Care to point to some patent? A diagram? Another processor
> > doing something similar? Anything at all that's not pulled out of thin air?).
> >
> > > Secondly it is one of the easiest optimizations to avoid reading memory operands multiple times. It has
> > > to be a deliberate choice (http://www.realworldtech.com/forum/?threadid=138897&curpostid=138966).
> >
> > Right, because compilers never have bugs and never emit
> > sub-optimal code for unreleased architectures. Never.
>
> It's clear that this L0 cache is a half baked idea predicated on some particularly terrible assumptions.
>
> First, register files are lower power than caches...

That is not universally true. Caches have fewer transistors per bit can operate at a longer latency, so a sufficiently small cache is more power efficient than a register file. Also, an L1 access requires additional power for the address generation/translation, but the L0 could use symbolic indexing.

KNC consumes only 40% more power for an instruction which acceses L1, versus an instruction which only uses registers: http://www.eecs.harvard.edu/~shao/papers/shao2013-islped.pdf Thus it's easy to see that an L0 cache with only a few entries would be more power efficient than both the L1 cache and the register file. Keeping a single L1 load port for KNL and even reducing the power consumption over register accesses with an L0 cache would be a very significant win Intel is not likely to overlook.

> somebody already pointed out that tagged vs.
> directly addressed structures suck. Nicolas is assuming otherwise, so that's a bad sign.

KNC's L1 is 8-way set associative, which consumes at least as much power as an 8-entry fully associative cache, just for the tag matching. The L0 cache I'm suggesting would need 2 entries per thread, maybe 4.

> Second, virtually addressed caches are a stupid idea. This should be evident from the fact that almost
> all high performance CPU caches are VIPT or PIPT. Also, how will this interact with threads?

The L0 cache I'm proposing would not be virtually addressed. It would use the instruction's encoding for the memory operand (i.e. the SIB byte, its EVEX extension bits, and part of the displacement bits). So you're 'symbolically' matching a memory operand that has been loaded before (e.g. [rax+r14*4] in Eric's example code). The entry would be invalidated if rax or r14 is written to, or when the entry's corresponding L1 cache line is modified/invalidated.

> Third, as Michael S pointed out - this is insanely brittle.

No more brittle than anything else happening in the L1 cache and LSU. It's basically a symbolically indexed line buffer with multiple entries and two read ports (http://caps.cs.binghamton.edu/papers/ghose_islped_1999.pdf). Shouldn't be too much of a challenge for Intel to design something like this.

> Fourth, the coherency implications are not considered.

That's because there are no coherency implications worth mentioning. It can be kept coherent with L1 at all time. Everything the LSU already does to keep L1 coherent, it can apply to L0 as well.

> Fifth, why would you want to create ANOTHER structure that stores must check?

The L0 cache would be read-only.

> I 100% agree with Gabriele here - the most logical explanation is that KNL
> isn't going to be released for a whole year, so the compiler is immature.

It's the same compiler since Larrabee. It's an utterly trivial optimization to use a register that already contains the data you need, instead of loading it from memory again. So this is a deliberate change for KNL and an indication that Intel *wants* to use memory operands instead of registers and thus it is highly likely that they are more power efficient. Which requires something like this L0 cache.

> I'll further add that I'm willing to wager that I'm correct about the 2 load
> pipelines, and that Nicolas is wrong about a virtually addressed L0 cache.

What exactly do you mean by 2 load pipelines? If you mean that both vector units would be able to use a memory operand in the same cycle, then yes, based on Eric's code that seems to be a necessity. However due to the duplicate loading of the same memory this can be provided by a dual-ported L0 cache, while the L1 cache itself only requires a single load port.
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TopicPosted ByDate
Knights Landing details (new article)David Kanter2014/01/03 12:58 AM
  eDRAM as cacheiz2014/01/03 04:39 AM
    eDRAM optionsEric Bron2014/01/09 03:45 AM
  Knights Landing details (new article)Emil Briggs2014/01/03 06:06 AM
  Knights Landing details (new article)Michael S2014/01/03 07:05 AM
    PCI-E and QPIDavid Kanter2014/01/03 12:11 PM
  eDRAM still seems too expensive ...Mark Roulo2014/01/03 10:48 AM
    Nevermind ... I see that you addressed this :-)Mark Roulo2014/01/03 10:51 AM
    eDRAM still seems too expensive ...Eric Bron2014/01/03 01:42 PM
  eDRAM or stacked DRAM?Patrick Chase2014/01/03 11:21 AM
    eDRAM or stacked DRAM?Wes Felter2014/01/03 03:00 PM
      eDRAM or stacked DRAM?Patrick Chase2014/01/03 07:26 PM
        eDRAM or stacked DRAM?tarlinian2014/06/23 09:59 PM
          eDRAM or stacked DRAM?Maynard Handley2014/06/24 01:47 AM
            eDRAM or stacked DRAM?Michael S2014/06/24 03:13 AM
            eDRAM or stacked DRAM?David Kanter2014/06/24 12:09 PM
              eDRAM or stacked DRAM?anon2014/06/24 07:50 PM
                eDRAM or stacked DRAM?Eric Bron2014/06/24 10:02 PM
                  eDRAM or stacked DRAM?anon2014/06/24 10:39 PM
                eDRAM or stacked DRAM?Michael S2014/06/25 01:46 AM
              eDRAM or stacked DRAM?Michael S2014/06/25 01:29 AM
          eDRAM or stacked DRAM?Eric Bron2014/06/24 05:37 AM
            eDRAM or stacked DRAM?tarlinian2014/06/24 08:53 AM
              eDRAM or stacked DRAM?Eric Bron2014/06/24 09:09 AM
                eDRAM or stacked DRAM?tarlinian2014/06/24 09:40 AM
                  eDRAM or stacked DRAM?Eric Bron2014/06/24 10:10 AM
                    eDRAM or stacked DRAM?Eric Bron2014/06/24 10:12 AM
          eDRAM or stacked DRAM?Wes Felter2014/06/24 10:09 PM
            eDRAM or stacked DRAM?Michael S2014/06/25 02:02 AM
  Why not tag-inclusive L3?Paul A. Clayton2014/01/03 04:28 PM
    Why not tag-inclusive L3?Eric Bron2014/01/04 03:22 AM
  Knights Landing L/S bandwidthNicolas Capens2014/01/04 05:43 AM
    Knights Landing L/S bandwidthEric Bron2014/01/04 06:20 AM
      Knights Landing L/S bandwidthNicolas Capens2014/01/04 02:55 PM
        Knights Landing L/S bandwidthEric Bron2014/01/04 03:27 PM
          Knights Landing L/S bandwidthhobold2014/01/04 04:23 PM
            Knights Landing L/S bandwidthEric Bron2014/01/04 05:20 PM
              Knights Landing L/S bandwidthMichael S2014/01/05 03:42 AM
                Knights Landing L/S bandwidthEric Bron2014/01/05 03:49 AM
                  Knights Landing L/S bandwidthPatrick Chase2014/01/11 08:13 PM
                    Knights Landing L/S bandwidthNicolas Capens2014/01/13 08:39 PM
                Knights Landing L/S bandwidthNicolas Capens2014/01/05 03:18 PM
                  Knights Landing L/S bandwidthMichael S2014/01/06 04:09 AM
                    Knights Landing L/S bandwidthEric Bron2014/01/06 05:11 AM
                      Knights Landing L/S bandwidthMichael S2014/01/06 05:40 AM
                        Knights Landing L/S bandwidthEric Bron2014/01/06 05:54 AM
                        Knights Landing L/S bandwidthEric Bron2014/01/08 09:00 AM
                    Knights Landing L/S bandwidthNicolas Capens2014/01/07 03:31 PM
                      Knights Landing L/S bandwidthMichael S2014/01/07 04:17 PM
                        Knights Landing L/S bandwidthNicolas Capens2014/01/07 09:55 PM
                          Knights Landing L/S bandwidthMichael S2014/01/08 01:42 AM
                            Knights Landing L/S bandwidthGabriele Svelto2014/01/08 08:30 AM
                              Occam's razorNicolas Capens2014/01/08 02:33 PM
                                Occam's razorGabriele Svelto2014/01/08 02:51 PM
                                  Occam's razorEric Bron2014/01/08 03:28 PM
                                    Occam's razorbakaneko2014/01/09 04:45 AM
                                      Occam's razoranon2014/01/09 05:02 AM
                                        Occam's razorbakaneko2014/01/09 06:24 AM
                                          Occam's razorbakaneko2014/01/09 06:51 AM
                                            Occam's razoranon2014/01/09 07:18 AM
                                          Occam's razoranon2014/01/09 07:16 AM
                                            Occam's razorbakaneko2014/01/09 08:43 AM
                                              Occam's razoranon2014/01/09 09:17 AM
                                                Occam's razorbakaneko2014/01/09 11:12 AM
                                                  Occam's razorEric Bron2014/01/09 11:18 AM
                                                    Occam's razorbakaneko2014/01/09 11:58 AM
                                                  Occam's razoranon2014/01/09 12:35 PM
                                                    Occam's razorbakaneko2014/01/12 10:48 AM
                                                  99.9% not a new extensionNicolas Capens2014/01/10 11:39 AM
                                                    Compiler complexityGabriele Svelto2014/01/11 03:58 AM
                                                      Compiler complexityNicolas Capens2014/01/11 01:20 PM
                                                        Compiler complexityGabriele Svelto2014/01/11 03:17 PM
                                                          Patent pendingNicolas Capens2014/01/14 07:21 PM
                                                    99.9% not a new extensionbakaneko2014/01/12 11:08 AM
                                  L0 data cacheEric Bron2014/01/08 04:52 PM
                                  Occam's razorDavid Kanter2014/01/08 04:53 PM
                                    Occam's razorNicolas Capens2014/01/09 03:07 AM
                                      Occam's razorRicardo B2014/01/09 05:21 AM
                                        Virtually indexed, untaggedNicolas Capens2014/01/10 11:27 AM
                                          Virtually indexed, untaggedGabriele Svelto2014/01/11 04:08 AM
                                            Virtually indexed, untaggedNicolas Capens2014/01/11 09:45 PM
                                              Virtually indexed, untaggedDavid Kanter2014/01/12 02:13 AM
                                                Virtually indexed, untaggedanon2014/01/12 04:02 AM
                                                Virtually indexed, untaggedNicolas Capens2014/01/16 09:55 AM
                                              Virtually indexed, untaggedMichael S2014/01/12 04:09 AM
                                                Virtually indexed, untaggedNicolas Capens2014/01/16 10:47 AM
                                      Occam's razorDavid Kanter2014/01/09 06:42 PM
                                        Occam's razorNicolas Capens2014/01/10 02:22 PM
                                          Occam's razorDavid Kanter2014/01/10 04:06 PM
                                            MEM : ALU ratioNicolas Capens2014/01/11 12:24 AM
                                              MEM : ALU ratioGabriele Svelto2014/01/11 03:47 AM
                                                MEM : ALU ratioEric Bron2014/01/11 04:41 AM
                                                  MEM : ALU ratioEric Bron2014/01/11 05:06 AM
                                                    MEM : ALU ratioDavid Kanter2014/01/11 08:28 PM
                                                      MEM : ALU ratioEric Bron nli2014/01/12 02:54 AM
                                                  MEM : ALU ratioGabriele Svelto2014/01/11 10:15 AM
                                                MEM : ALU ratioNicolas Capens2014/01/14 06:56 PM
                                                  Etiquette in linking to papersPaul A. Clayton2014/01/14 07:44 PM
                                                  MEM : ALU ratioanon2014/01/14 08:32 PM
                                                    L0 power costNicolas Capens2014/01/16 02:05 PM
                                                      L0 power costanon2014/01/16 10:01 PM
                                                        L0 power costNicolas Capens2014/01/19 12:30 AM
                                                          Links revealedPaul A. Clayton2014/01/19 04:47 PM
                                                          L0 power costanon2014/01/20 01:19 AM
                                                            L0 power costNicolas Capens2014/01/20 02:49 PM
                                                              L0 power costanon2014/01/21 01:18 AM
                                                                Q.E.D.Nicolas Capens2014/01/21 08:44 PM
                                                                  Q.E.D.anon2014/01/21 09:24 PM
                                                                    Straw manNicolas Capens2014/01/23 11:56 PM
                                                                      Straw mananon2014/01/25 06:46 AM
                                                                        Still waiting for an explanationNicolas Capens2014/01/26 12:19 AM
                                                                          Still waiting for an explanationExophase2014/01/26 01:13 PM
                                                                            Still waiting for an explanationbakaneko2014/01/26 11:52 PM
                                                                  Q.E.D.Ricardo B2014/01/22 06:58 PM
                                                                    Q.E.D.Michael S2014/01/23 04:59 AM
                                                                      L0 entry countNicolas Capens2014/01/24 01:11 AM
                                                                        L0 entry countEric Bron2014/01/24 02:08 AM
                                                                          L0 entry countMichael S2014/01/24 06:18 AM
                                                                            L0 entry countEric Bron2014/01/24 07:15 AM
                                                                              L0 entry countMichael S2014/01/24 08:10 AM
                                                                                L0 entry countEric Bron2014/01/24 08:20 AM
                                                                          L0 entry countNicolas Capens2014/01/24 02:33 PM
                                                                            L0 entry countEric Bron2014/01/24 03:20 PM
                                                                              L0 entry count and L1 read port orthogonalityNicolas Capens2014/01/26 01:14 AM
                                                                                L0 entry count and L1 read port orthogonalityEric Bron2014/01/26 03:49 AM
                                                                    L0 hit rateNicolas Capens2014/01/24 12:49 AM
                                                                      L0 hit rateRicardo B2014/01/24 06:42 AM
                                                                        L0 hit rateExophase2014/01/24 01:37 PM
                                                                          L0 hit rateEric Bron2014/01/24 02:12 PM
                                                                        L0 vs RF powerNicolas Capens2014/01/24 02:43 PM
                                              MEM : ALU ratioDavid Kanter2014/01/11 01:47 PM
                                                MEM : ALU ratioNicolas Capens2014/01/16 09:23 AM
                                                  MEM : ALU ratioStubabe2014/01/17 12:58 PM
                                                    MEM : ALU ratioStubabe2014/01/17 01:42 PM
                                                      MEM : ALU ratioMichael S2014/01/18 04:57 PM
                                                        MEM : ALU ratiobakaneko2014/01/19 12:47 AM
                                                    MEM : ALU ratioNicolas Capens2014/01/20 03:48 PM
                                                      It's called "tunnel vision" (NT)iz2014/01/20 04:36 PM
                                                      MEM : ALU ratioMichael S2014/01/20 04:37 PM
                                                        MEM : ALU ratioStubabe2014/01/21 04:54 PM
                                                        MEM : ALU ratioNicolas Capens2014/01/21 10:07 PM
                                                          MEM : ALU ratioMichael S2014/01/22 08:17 AM
                                                            MEM : ALU ratioNicolas Capens2014/01/24 03:33 PM
                                                      MEM : ALU ratioStubabe2014/01/21 04:32 PM
                                                        MEM : ALU ratioMichael S2014/01/22 08:56 AM
                                                          MEM : ALU ratioStubabe2014/01/23 09:06 AM
                                                            MEM : ALU ratioEric Bron2014/01/23 09:45 AM
                                                              editEric Bron2014/01/23 09:49 AM
                                                            MEM : ALU ratioMichael S2014/01/23 09:58 AM
                                                              MEM : ALU ratioEric Bron2014/01/23 10:29 AM
                                                                MEM : ALU ratioMichael S2014/01/23 10:33 AM
                                                              MEM : ALU ratioStubabe2014/01/24 04:50 AM
                                                MEM : ALU ratiobakaneko2014/01/23 10:36 AM
                                              MEM : ALU ratioNoSpammer2014/01/11 03:39 PM
                                                L1 vs L0 access costNicolas Capens2014/01/16 03:17 PM
                                                  L1 vs L0 access costNoSpammer2014/01/19 01:48 PM
                                                    L1 vs L0 access costdmcq2014/01/22 05:45 AM
                                                      L1 vs L0 access costGabriele Svelto2014/01/22 07:29 AM
                                                        L1 vs L0 access costdmcq2014/01/22 01:33 PM
                                                          L1 vs L0 access costGabriele Svelto2014/01/22 04:33 PM
                                                            L1 vs L0 access costdmcq2014/01/24 04:19 AM
                                                    L1 vs L0 access costNicolas Capens2014/01/24 02:16 AM
                                      Occam's razorPatrick Chase2014/01/13 11:19 AM
                                  Occam's razorNicolas Capens2014/01/09 12:40 AM
                                    Occam's razorGabriele Svelto2014/01/09 02:41 AM
                                      Occam's razorEric Bron2014/01/09 02:54 AM
                                        Occam's razorGabriele Svelto2014/01/09 06:35 AM
                                          Occam's razorEric Bron2014/01/09 07:14 AM
                                            avoiding redundant loadsEric Bron2014/01/09 07:18 AM
                                            AVX2 versionEric Bron2014/01/09 07:32 AM
                                      Occam's razorAmiba Gelos2014/01/09 03:01 AM
                                        Occam's razorEric Bron2014/01/09 03:06 AM
                                          Occam's razorAmiba Gelos2014/01/09 03:43 AM
                                            Occam's razorEric Bron2014/01/09 04:02 AM
                                        L0 access latencyNicolas Capens2014/01/09 04:27 AM
                                          L0 access latencyAmiba Gelos2014/01/09 05:16 AM
                                            compared to L0$ i would say banking is far more likely (NT)Amiba Gelos2014/01/09 05:20 AM
                                            L0 access latencyNicolas Capens2014/01/10 03:20 PM
                                      Occam's razorNicolas Capens2014/01/09 04:19 AM
                                    Occam's razorNoSpammer2014/01/09 12:55 PM
                                      Occam's razorNicolas Capens2014/01/10 03:40 PM
                                        Occam's razorMichael S2014/01/11 10:21 AM
                                        Occam's razorMichael S2014/01/12 03:21 PM
                                          KNC compiler outputNicolas Capens2014/01/16 06:39 PM
                                            KNC compiler outputMichael S2014/01/18 05:13 PM
                                    L0 cache coherencyDavid Kanter2014/01/11 08:39 PM
                                Occam's razoranon2014/01/09 05:12 AM
                            Knights Landing L/S bandwidthEric Bron2014/01/08 10:46 AM
                              Knights Landing L/S bandwidthMichael S2014/01/08 11:23 AM
                            Knights Landing L/S bandwidthNicolas Capens2014/01/08 02:02 PM
                              Knights Landing L/S bandwidthMichael S2014/01/08 02:29 PM
                                Knights Landing L/S bandwidthEric Bron2014/01/08 02:54 PM
                                  Knights Landing L/S bandwidthMichael S2014/01/08 03:00 PM
                                    Knights Landing L/S bandwidthEric Bron2014/01/08 03:13 PM
                                      Knights Landing L/S bandwidthMichael S2014/01/08 03:28 PM
                                        Knights Landing L/S bandwidthEric Bron2014/01/08 03:32 PM
                                          Knights Landing L/S bandwidthMichael S2014/01/08 03:40 PM
                                            Knights Landing L/S bandwidthEric Bron2014/01/08 03:51 PM
                                              Knights Landing L/S bandwidthMichael S2014/01/09 12:18 PM
                          Knights Landing L/S bandwidthPatrick Chase2014/01/12 10:03 PM
                            Also page/line splits?David Kanter2014/01/12 10:50 PM
                              Also page/line splits?anon2014/01/13 01:44 AM
                                Also page/line splits?none2014/01/13 03:09 AM
                                  Also page/line splits?anon2014/01/13 04:19 AM
                            Knights Landing L/S bandwidthExophase2014/01/13 12:15 AM
                            Knights Landing L/S bandwidthanon2014/01/13 01:41 AM
                              Knights Landing L/S bandwidthPatrick Chase2014/01/13 11:14 AM
                            Aliased writesNicolas Capens2014/01/14 09:46 PM
                      Knights Landing L/S bandwidthRicardo B2014/01/07 04:27 PM
                        Knights Landing L/S bandwidthNicolas Capens2014/01/07 10:28 PM
                          Knights Landing L/S bandwidthRicardo B2014/01/08 02:13 AM
                            Knights Landing L/S bandwidthEric Bron2014/01/08 11:10 AM
                            Knights Landing L/S bandwidthNicolas Capens2014/01/08 03:31 PM
                              Knights Landing L/S bandwidthRicardo B2014/01/08 03:58 PM
                                Knights Landing L/S bandwidthG. Gouvine2014/01/09 09:10 AM
                                  Knights Landing L/S bandwidthRicardo B2014/01/09 11:19 AM
                                    Efficient load queue vs. efficient L0 cacheNicolas Capens2014/01/11 12:28 PM
                                      Efficient load queue vs. efficient L0 cacheG. Gouvine2014/01/13 02:11 AM
                                        Efficient load queue vs. efficient L0 cacheMichael S2014/01/13 03:43 AM
                                Register file read port requirementsNicolas Capens2014/01/11 12:55 AM
                                  Register file read port requirementsRicardo B2014/01/11 05:24 AM
                                    Register file read port requirementsEric Bron2014/01/11 05:32 AM
                                      Register file read port requirementsMichael S2014/01/11 09:57 AM
                                        Register file read port requirementsEric Bron2014/01/11 11:16 AM
                                          Register file read port requirementsMichael S2014/01/11 11:46 AM
                                            Register file read port requirementsEric Bron2014/01/11 12:12 PM
                                              Register file read port requirementsMichael S2014/01/11 12:36 PM
                                                Register file read port requirementsEric Bron2014/01/11 12:51 PM
                                              Register file read port requirementsPatrick Chase2014/01/13 02:27 PM
                                                Register file read port requirementsEric Bron2014/01/13 04:24 PM
                                                  Register file read port requirementsPatrick Chase2014/01/13 06:02 PM
                                                    Register file read port requirementsEric Bron2014/01/14 04:50 AM
                                                      Register file read port requirementsMichael S2014/01/14 11:36 AM
                                                        Register file read port requirementsEric Bron nli2014/01/14 01:04 PM
                                            Register file read port requirementsPatrick Chase2014/01/13 02:17 PM
                                              Register file read port requirementsMichael S2014/01/15 04:27 AM
                                        Register file read port requirementsEric Bron2014/01/11 11:28 AM
                                          Register file read port requirementsMichael S2014/01/11 12:07 PM
                                            Register file read port requirementsPatrick Chase2014/01/13 02:40 PM
                                          Register file read port requirementsPatrick Chase2014/01/13 02:34 PM
                                      Register file read port requirementsRicardo B2014/01/11 12:55 PM
                                        Register file read port requirementsEric Bron2014/01/11 01:17 PM
                                          Register file read port requirementsRicardo B2014/01/11 02:36 PM
                                            Register file read port requirementsEric Bron2014/01/11 02:42 PM
                                              Register file read port requirementsRicardo B2014/01/11 03:20 PM
                                                Register file read port requirementsEric Bron2014/01/11 03:26 PM
                                                  Register file read port requirementsMichael S2014/01/11 04:07 PM
                                                    Register file read port requirementsRicardo B2014/01/11 04:38 PM
                                                      Register file read port requirementsMichael S2014/01/11 04:49 PM
                                                Register file read port requirementsEric Bron2014/01/11 03:39 PM
                                                  Register file read port requirementsEric Bron2014/01/11 03:41 PM
                                                  Register file read port requirementsRicardo B2014/01/11 04:30 PM
                                    Register file read port requirementsNicolas Capens2014/01/11 12:09 PM
              Knights Landing L/S bandwidthanon2014/01/05 06:55 AM
                Knights Landing L/S bandwidthEric Bron2014/01/05 07:30 AM
                  Knights Landing L/S bandwidthanon2014/01/06 01:07 AM
                    Knights Landing L/S bandwidthEric Bron2014/01/06 02:38 AM
                      Knights Landing L/S bandwidthanon2014/01/06 04:01 AM
                        Knights Landing L/S bandwidthEric Bron2014/01/06 04:44 AM
                          Knights Landing L/S bandwidthanon2014/01/06 05:39 AM
                            Knights Landing L/S bandwidthEric Bron2014/01/06 06:00 AM
                              Knights Landing L/S bandwidthanon2014/01/06 06:44 AM
                                Knights Landing L/S bandwidthMichael S2014/01/06 08:54 AM
                                  Knights Landing L/S bandwidthEric Bron2014/01/06 10:11 AM
                                    Knights Landing L/S bandwidthMichael S2014/01/06 10:14 AM
                                      Knights Landing L/S bandwidthEric Bron2014/01/06 11:37 AM
                                        Knights Landing L/S bandwidthRicardo B2014/01/08 06:25 AM
                                          Knights Landing L/S bandwidthEric Bron2014/01/08 08:36 AM
                                            Knights Landing L/S bandwidthEric Bron2014/01/08 08:41 AM
                                            KNC code generator with EVEX back-end?Michael S2014/01/08 09:43 AM
                                              KNC code generator with EVEX back-end?Exophase2014/01/08 10:00 AM
                                                KNC code generator with EVEX back-end?Ricardo B2014/01/08 11:39 AM
                                                  KNC code generator with EVEX back-end?Eric Bron2014/01/08 12:15 PM
                                                    KNC code generator with EVEX back-end?Exophase2014/01/08 01:17 PM
                                                      KNC code generator with EVEX back-end?Ricardo B2014/01/08 02:06 PM
                                                        KNC code generator with EVEX back-end?Exophase2014/01/08 02:24 PM
                                                        KNC code generator with EVEX back-end?Eric Bron2014/01/08 02:38 PM
                                                    KNC code generator with EVEX back-end?Michael S2014/01/08 01:54 PM
                                              KNC code generator with EVEX back-end?Eric Bron2014/01/08 10:25 AM
                                              KNC code generator with EVEX back-end?Eric Bron2014/01/08 10:35 AM
                                                KNC code generator with EVEX back-end?Michael S2014/01/08 11:07 AM
                                                  KNC code generator with EVEX back-end?Eric Bron2014/01/08 11:24 AM
                                                    KNC code generator with EVEX back-end?Michael S2014/01/08 11:43 AM
                                                      KNC code generator with EVEX back-end?Eric Bron2014/01/08 01:23 PM
                                              KNC code generator with EVEX back-end?Eric Bron2014/01/08 10:43 AM
                                          AVX2 code much different than AVX-512Eric Bron2014/01/08 08:52 AM
                                            evil questionhobold2014/01/08 10:22 AM
                                              evil questionEric Bron2014/01/08 10:27 AM
                                                evil questionhobold2014/01/08 02:33 PM
                                                  evil questionMichael S2014/01/08 02:37 PM
                                                    stupid question (was: evil question)hobold2014/01/09 05:41 AM
                                                      stupid question (was: evil question)Eric Bron2014/01/09 05:52 AM
                                                        stupid question (was: evil question)Michael S2014/01/09 08:00 AM
                                                          stupid question (was: evil question)Michael S2014/01/09 08:12 AM
                                                            stupid question (was: evil question)Eric Bron2014/01/09 10:47 AM
                                                              stupid question (was: evil question)Michael S2014/01/09 11:48 AM
                                                                more decisive (hopefully) test caseMichael S2014/01/09 12:01 PM
                                                                  more decisive (hopefully) test caseEric Bron2014/01/09 12:08 PM
                                                                    more decisive (hopefully) test caseMichael S2014/01/09 12:24 PM
                                                                      more decisive (hopefully) test caseEric Bron2014/01/09 12:27 PM
                                                                        more decisive (hopefully) test caseMichael S2014/01/09 12:33 PM
                                                                  AVX2Eric Bron2014/01/09 12:14 PM
                                                                    AVX2Michael S2014/01/09 12:30 PM
                                                                      AVX2Eric Bron2014/01/09 12:40 PM
                                                                  another tryMichael S2014/01/09 03:02 PM
                                                                    another tryEric Bron2014/01/09 03:33 PM
                                                                      another tryMichael S2014/01/09 04:20 PM
                                                                      another try - ignore misformated mess aboveMichael S2014/01/09 04:24 PM
                                                                        another try - ignore misformated mess aboveGabriele Svelto2014/01/10 01:01 AM
                                                                          another try - ignore misformated mess aboveEric Bron2014/01/10 03:05 AM
                                                                            another try - ignore misformated mess aboveMichael S2014/01/11 10:23 AM
                                                                              another try - ignore misformated mess aboveEric Bron2014/01/11 11:08 AM
                                                                                another try - ignore misformated mess aboveMichael S2014/01/11 12:09 PM
                                                                                  another try - ignore misformated mess aboveMichael S2014/01/11 12:12 PM
                                                                                    another try - ignore misformated mess aboveEric Bron2014/01/11 12:24 PM
                                                                                      another try - ignore misformated mess aboveMichael S2014/01/11 01:24 PM
                                                                                        another try - ignore misformated mess aboveEric Bron2014/01/11 02:11 PM
                                                                                          another try - ignore misformated mess aboveMichael S2014/01/11 02:18 PM
                                                                                            another try - ignore misformated mess aboveEric Bron2014/01/11 02:27 PM
                                                                                              another try - ignore misformated mess aboveMichael S2014/01/11 02:29 PM
                                                                                                another try - ignore misformated mess aboveEric Bron2014/01/11 02:46 PM
                                                                                                  another try - ignore misformated mess aboveEric Bron2014/01/11 02:46 PM
                                                                                                  another try - ignore misformated mess aboveMichael S2014/01/11 03:28 PM
                                                                                        another try - ignore misformated mess aboveEric Bron2014/01/11 02:17 PM
                                                                                          another try - ignore misformated mess aboveMichael S2014/01/11 02:24 PM
                                                                    KNC versionMichael S2014/01/11 05:19 PM
                                                                      KNC versionEric Bron nli2014/01/12 02:59 AM
                                                                        KNC versionGabriele Svelto2014/01/12 09:06 AM
                                                  evil questionEric Bron2014/01/08 02:41 PM
              Knights Landing L/S bandwidthPatrick Chase2014/01/05 11:20 PM
                Knights Landing L/S bandwidthEric Bron2014/01/06 02:45 AM
                  Knights Landing L/S bandwidthanon2014/01/06 04:12 AM
                    Knights Landing L/S bandwidthMichael S2014/01/06 04:17 AM
                      Knights Landing L/S bandwidthanon2014/01/06 05:20 AM
          Knights Landing L/S bandwidthNicolas Capens2014/01/04 05:34 PM
            Knights Landing L/S bandwidthEric Bron2014/01/04 05:44 PM
              Knights Landing L/S bandwidthNicolas Capens2014/01/05 12:25 PM
                Knights Landing L/S bandwidthEric Bron2014/01/05 01:50 PM
                  Knights Landing L/S bandwidthNicolas Capens2014/01/05 03:34 PM
                    Might even help with gatherNicolas Capens2014/01/05 03:40 PM
                      What is an L0 cache?David Kanter2014/01/05 10:44 PM
                        What is an L0 cache?anon2014/01/06 05:57 AM
                          What is an L0 cache?Nicolas Capens2014/01/06 12:57 PM
                            What is an L0 cache?anon2014/01/06 02:18 PM
    Knights Landing L/S bandwidthDavid Kanter2014/01/04 10:58 AM
      Knights Landing L/S bandwidthNicolas Capens2014/01/04 04:24 PM
        Knights Landing L/S bandwidthEric Bron2014/01/04 04:46 PM
          Knights Landing L/S bandwidthKonrad Schwarz2014/01/08 12:48 AM
            Knights Landing L/S bandwidthMichael S2014/01/08 02:45 AM
        Knights Landing L/S bandwidthDavid Kanter2014/01/05 01:44 AM
          Knights Landing L/S bandwidthEric Bron2014/01/05 03:55 AM
          Knights Landing L/S bandwidthNicolas Capens2014/01/05 12:18 PM
            Knights Landing L/S bandwidthMaynard Handley2014/01/05 11:33 PM
              Knights Landing L/S bandwidthEric Bron2014/01/06 04:02 AM
                Knights Landing L/S bandwidthMichael S2014/01/06 04:23 AM
                  Knights Landing L/S bandwidthEric Bron2014/01/06 04:35 AM
                    Knights Landing L/S bandwidthMichael S2014/01/06 05:20 AM
                      Knights Landing L/S bandwidthMichael S2014/01/06 05:32 AM
                      Knights Landing L/S bandwidthEric Bron2014/01/06 05:36 AM
                        Knights Landing L/S bandwidthMichael S2014/01/06 06:00 AM
                          Knights Landing L/S bandwidthEric Bron2014/01/06 06:07 AM
                          Knights Landing L/S bandwidthEric Bron2014/01/06 06:14 AM
                            editsEric Bron2014/01/06 06:22 AM
                              optimized versionEric Bron2014/01/06 06:35 AM
                                yet more optimized versionEric Bron2014/01/06 06:42 AM
                                  latest version for todayEric Bron2014/01/06 06:51 AM
                                    Probably just L2 bandwith limitedNicolas Capens2014/01/06 11:48 AM
                                  yet more optimized versionMaynard Handley2014/01/06 06:54 PM
                                optimized versionMaynard Handley2014/01/06 06:52 PM
                                  optimized versionMichael S2014/01/07 10:42 AM
                                    optimized versionNicolas Capens2014/01/07 12:36 PM
                                      optimized versionMichael S2014/01/07 03:41 PM
                                        optimized versionNicolas Capens2014/01/07 10:52 PM
                                          optimized versionMichael S2014/01/08 02:10 AM
                                    optimized versionEric Bron2014/01/07 02:34 PM
                                      optimized versionMichael S2014/01/07 03:18 PM
                                        optimized versionEric Bron2014/01/07 03:30 PM
                                          optimized versionEric Bron2014/01/07 03:33 PM
                                            optimized versionMichael S2014/01/07 03:57 PM
                                    optimized versionMaynard Handley2014/01/07 06:50 PM
                                      optimized versionMichael S2014/01/08 02:39 AM
                Knights Landing L/S bandwidthMaynard Handley2014/01/06 06:47 PM
              Knights Landing L/S bandwidthNicolas Capens2014/01/06 09:18 AM
                Knights Landing L/S bandwidthMaynard Handley2014/01/06 06:56 PM
                  Knights Landing L/S bandwidthNicolas Capens2014/01/07 12:18 PM
        Knights Landing L/S bandwidthNoSpammer2014/01/05 01:15 PM
          Knights Landing L/S bandwidthNicolas Capens2014/01/05 03:06 PM
            Knights Landing L/S bandwidthNoSpammer2014/01/06 04:20 AM
              Knights Landing L/S bandwidthNicolas Capens2014/01/06 11:54 AM
                Knights Landing L/S bandwidthNoSpammer2014/01/06 01:24 PM
                  Knights Landing L/S bandwidthNicolas Capens2014/01/06 09:15 PM
                    Knights Landing L/S bandwidthNoSpammer2014/01/07 03:58 AM
                      Knights Landing L/S bandwidthNicolas Capens2014/01/07 03:18 PM
                        Knights Landing L/S bandwidthNoSpammer2014/01/08 01:38 PM
                          Knights Landing L/S bandwidthNicolas Capens2014/01/08 11:14 PM
  AVX512F questionMichael S2014/01/06 10:18 AM
    AVX512F questionNicolas Capens2014/01/06 12:01 PM
  Knights Landing - time for obituary?Michael S2018/07/31 03:00 PM
    Knights Landing - time for obituary?Adrian2018/07/31 09:24 PM
      Knights Landing - time for obituary?SoftwareEngineer2018/08/01 02:15 AM
        auto-vectorization is a dead endMichael S2018/08/01 03:48 AM
          Auto-vectorization of random C is a dead endMark Roulo2018/08/01 11:07 AM
            Auto-vectorization of random C is a dead endPassing Through2018/08/01 01:35 PM
              Auto-vectorization of random C is a dead endDavid Kanter2018/08/01 10:44 PM
                Auto-vectorization of random C is a dead endPassing Through2018/08/02 01:51 AM
            Auto-vectorization of random C is a dead endSoftwareEngineer2018/08/02 01:19 AM
              Auto-vectorization of random C is a dead endMark Roulo2018/08/02 09:50 AM
                Auto-vectorization of random C is a dead endMichael S2018/08/02 12:11 PM
                  Auto-vectorization of random C is a dead endj2018/08/02 11:37 PM
                    Auto-vectorization of random C is a dead endMichael S2018/08/03 03:50 AM
                      Auto-vectorization of random C is a dead endrwessel2018/08/03 11:06 PM
                  Auto-vectorization of random C is a dead endRicardo B2018/08/03 04:20 AM
                    Auto-vectorization of random C is a dead endMichael S2018/08/03 05:37 AM
                      Auto-vectorization of random C is a dead endRicardo B2018/08/03 11:22 AM
            Auto-vectorization of random C is a dead endTravis2018/08/03 07:58 PM
              Potential way to autovectorization in the future. Jouni Osmala2018/08/03 10:22 PM
                Potential way to autovectorization in the future. Jukka Larja2018/08/04 04:03 AM
                  Potential way to autovectorization in the future. Passing Through2018/08/04 06:47 AM
                Potential way to autovectorization in the future. Travis2018/08/04 01:50 PM
                  Potential way to autovectorization in the future. Michael S2018/08/04 02:33 PM
                    Potential way to autovectorization in the future. Travis2018/08/04 02:48 PM
                    Potential way to autovectorization in the future. Passing Through2018/08/04 02:58 PM
                  Skylake server/client AVX PRF speculationJeff S.2018/08/04 05:42 PM
                    Skylake server/client AVX PRF speculationanonymou52018/08/04 06:21 PM
                      Skylake server/client AVX PRF speculationJeff S.2018/08/04 06:38 PM
                        Skylake server/client AVX PRF speculationanonymou52018/08/04 07:45 PM
                          Skylake server/client AVX PRF speculationJeff S.2018/08/04 08:08 PM
                            Skylake server/client AVX PRF speculationanonymou52018/08/04 08:18 PM
                              Skylake server/client AVX PRF speculationNomad2018/08/05 11:10 PM
                                Skylake server/client AVX PRF speculationanonymou52018/08/06 12:14 PM
                                Skylake server/client AVX PRF speculationTravis2018/08/06 08:43 PM
                            Skylake server/client AVX PRF speculationTravis2018/08/06 08:39 PM
              Auto-vectorization of random C is a dead endBrett2018/08/04 01:55 PM
                Auto-vectorization of random C is a dead endTravis2018/08/04 02:38 PM
                  Auto-vectorization of random C is a dead endPassing Through2018/08/04 03:00 PM
                    New record for shortest post by Ireland - AI crashed? (NT)Travis2018/08/04 03:34 PM
                      New record for shortest post by Ireland - AI crashed?Passing Through2018/08/04 04:12 PM
                        New record for shortest post by Ireland - AI crashed?anonymou52018/08/04 06:00 PM
                          New record for shortest post by Ireland - AI crashed?Brett2018/08/04 06:40 PM
                            New record for shortest post by Ireland - AI crashed?anonymou52018/08/04 07:38 PM
                  Auto-vectorization of random C is a dead endnoko2018/08/04 09:46 PM
        The story of ispc (a 12 entry blog series)Simon Farnsworth2018/08/01 03:50 AM
          the 1st link is empty (NT)Michael S2018/08/01 04:05 AM
            the 1st link is emptySimon Farnsworth2018/08/01 06:42 AM
          Interesting read, thanks! (NT)SoftwareEngineer2018/08/01 06:57 AM
          Amazing readLaurent2018/08/01 09:00 AM
            Amazing readPassing Through2018/08/01 01:13 PM
              Amazing readDoug S2018/08/01 02:30 PM
                Amazing readPassing Through2018/08/01 02:49 PM
          ISPC vs OpenCL?j2018/08/02 11:41 PM
            ISPC vs OpenCL?coppcie2018/08/03 03:55 AM
            ISPC vs OpenCL?Passing Through2018/08/03 04:07 AM
              Go awayForum Reader2018/08/03 08:11 AM
              ISPC vs OpenCL?Gian-Carlo Pascutto2018/09/11 06:50 AM
            ISPC vs OpenCL?SoftwareEngineer2018/08/03 04:18 AM
        Knights Landing - time for obituary?Kevin G2018/08/01 07:14 AM
          Knights Landing - time for obituary?SoftwareEngineer2018/08/01 07:29 AM
        Knights Landing - time for obituary?Passing Through2018/08/01 07:38 AM
          Knights Landing - time for obituary?Eric Bron2018/08/02 06:57 AM
            Knights Landing - time for obituary?Passing Through2018/08/02 12:29 PM
              Knights Landing - time for obituary?Eric Bron2018/08/02 01:49 PM
                Knights Landing - time for obituary?Passing Through2018/08/02 02:17 PM
          chess algorithms vs, low level optimizationsEric Bron2018/08/02 07:15 AM
            AlphaZero vs StockfishMichael S2018/08/02 07:55 AM
              AlphaZero vs StockfishEric Bron2018/08/02 08:24 AM
                AlphaZero vs StockfishMichael S2018/08/02 09:01 AM
                  AlphaZero vs StockfishEric Bron2018/08/02 09:11 AM
                  Leela 4th vs all othersEric Bron nli2018/09/11 03:40 AM
              AlphaZero vs StockfishGian-Carlo Pascutto2018/09/11 06:31 AM
                AlphaZero vs StockfishEric Bron2018/09/11 09:26 AM
                  AlphaZero vs StockfishEric Bron2018/09/11 09:58 AM
        C/C++ and vector/parallel/distributedRichardC2018/08/02 05:50 AM
      Knights Landing - time for obituary?Passing Through2018/08/01 07:52 AM
        Knights Landing - time for obituary?Kevin G2018/08/01 02:03 PM
          Knights Landing - time for obituary?Passing Through2018/08/01 02:33 PM
      Knights Landing - time for obituary?Kevin G2018/08/01 08:26 AM
        Knights Landing - time for obituary?Kevin G2018/08/01 08:26 AM
        Knights Landing - time for obituary?juanrga2018/08/01 02:26 PM
          Knights Landing - time for obituary?hobel2018/08/02 05:46 AM
    Knights Landing - time for obituary?juanrga2018/07/31 11:25 PM
      Right, time for obituary for whole LRB lineageAM2018/08/02 11:46 AM
        Right, time for obituary for whole LRB lineageAdrian2018/08/02 11:46 PM
          LRBNI, AVX512, etc...Michael S2018/08/03 05:23 AM
        Right, time for obituary for whole LRB lineagejuanrga2018/08/03 04:11 AM
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How do you spell green?