L1 vs L0 access cost

Article: Knights Landing Details
By: Nicolas Capens (nicolas.capens.delete@this.gmail.com), January 24, 2014 2:16 am
Room: Moderated Discussions
NoSpammer (no.delete@this.spam.com) on January 19, 2014 1:48 pm wrote:
> Nicolas Capens (nicolas.capens.delete@this.gmail.com) on January 16, 2014 3:17 pm wrote:
> > The 40% is for the same arithmetic instruction, with a memory source operand instead of a register,
> > hitting L1. So accessing L1 has a very substantial cost of 40% per cycle, not 13.33%.
>
> That's bad then but that's why there are registers.

Sure, but we can do even better than that. The L0 cache would only have a few entries and two read ports, versus the register file which has 32 entries and multiple read ports. So accessing the L0 as often as possible instead of the RF, saves power, and on top of that the RF's read port count can be reduced for even more savings. Not only that, reusing data from memory by using a register requires adding a separate load instruction. Finally, the L0 cache would allow to have just one L1 read port instead of two.

So the L0 could achieve no less than a quadruple power saving, while with only a couple of entries it would cost next to nothing itself.

> > It's not a fixed idea. I can let go of it in a heartbeat. But someone still has to
> > provide any reasonable explanation why an extremely tiny cache which only requires
> > a handful of small comparators to find hits on reads and invalidate entries on write,
> > would not be power efficient enough to save some of the L1's 40% access power.
>
> No one disputes this.

Actually several people seem to disagree, but I'm glad you think it's undisputed.

> The question is about the utility especially in the power hungry cases
> where L1,L2 & memory controller are fully exercised but L0 is only burning some extra power.

GPU manufacturers are putting very considerable effort into optimizing the power consumption of the register files with smaller operand register files or register caches. So that should give you some idea of the importance of optimizing the accesses to the data that is already the closest to the execution units. The things is that while an L2 access consumes more power than an L1 access, the latter in general occurs much more frequently. Likewise the L0 accesses would occur even more frequently since the compiler is directed to reuse memory operands instead of registers.

I'm sure there are a few scenario's where you're bottlenecked by L1 (or L2 or RAM) and the L0 is just burning (a tiny bit of) wasted power. But that's true for the L1 as well when you're bottlenecked by L2. Heck it's true of the register file. So you have to evaluate things over the entirety of use cases. Since the compiler is instructed to reuse memory operands, the L0 would typically be used very frequently and save a lot of accesses to L1 which would have costed substantially more power.

> > This isn't about a minor tweak in "optimality". Loading data from memory again when it's already
> > in a register is a big deal and yet a trivial optimization. They do it for other architectures.
> > So I don't think I'm being naive about having faith in Intel's compiler engineers being capable
> > of this optimization. They must have disabled it deliberately for a reason.
>
> I've been using Intel compilers for more than 10 years and I could fill at least 20 pages with stupidities
> generated by the compiler. It's work in progress. Sometimes a new version of the compiler generates worse
> code for the source at hand. Sometimes you get a better result targeting a different CPU. Looking at a few
> cases does not prove much. What I've also noticed with the latest versions is that you can get a rather
> generic compile of a function and a totally different compile when that same function is inlined in another
> loop. Sometimes a loop is not unrolled. Then you unroll it 4 times by hand and the compiler finally decides
> it will unroll it one more time. It's obviously a bit of a gamble which heuristic kicks in.

I'm sorry but I still don't think you appreciate just how radically different this is from typical compiler flakiness. All the examples consistently reuse memory operands, even in situations where it would be utterly trivial to use a register instead. These aren't corner cases where you might expect some hickups; it's very typical and straightforward code and it is downright impossible that the Intel engineers would not have noticed this. The AVX2 code looks entirely as expected so clearly they know what they're doing.
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TopicPosted ByDate
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              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
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      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?