you are wrong at about 100% of you said

By: Linus Torvalds (torvalds.delete@this.linux-foundation.org), July 13, 2013 11:08 am
Room: Moderated Discussions
That was very informative of you. However, you seem to forget that we've actually gone through this before, in the MMX->XMM transition with SSE2.

So we actually know how people tried to save transistors and effort before, when the 64->128 bit expansion happened. It was AMD back then, but they did exactly the simple half-wide approach. And it didn't work out all that well. They had exactly the issues I brought up.

And we had that same "unaligned loads are slow" issue, which was a disaster too, and eventually fixed - by basically doubling the memory access path.

So we've seen the the whole SSE->AVX thing before, just in the guise of MMX->SSE. The issues aren't that different..

But at the same time there's a big difference: the upsides have shrunk. SSE is "good enough" for most things.

Five years from now? Who knows? Maybe people will clamor for AVX. And with another shrink or two, the costs are smaller too. Right now I'm not seeing it. You (or anybody else, for that matter) haven't brought up any realistic case that would be relevant on mobile or microservers that would warrant AVX.

So why are you so convinced AVX makes sense?

Linus
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                                    Saltwell Outperforming A15...With Less Power!!!Wilco2013/07/11 12:04 AM
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                                                Saltwell Outperforming A15...With Less Power!!!none2013/07/16 05:34 AM
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                                    Saltwell Outperforming A15...With Less Power!!!Linus Torvalds2013/07/11 10:20 AM
                                      Saltwell Outperforming A15...With Less Power!!!Ian Ameline2013/07/11 02:20 PM
                                      Saltwell Outperforming A15...With Less Power!!!Sylvain Collange2013/07/12 01:29 AM
                                        Saltwell Outperforming A15...With Less Power!!!Wilco2013/07/12 02:51 AM
                                          Saltwell Outperforming A15...With Less Power!!!Sylvain Collange2013/07/12 05:00 AM
                                      Saltwell Outperforming A15...With Less Power!!!bakaneko2013/07/12 02:28 AM
                                        Saltwell Outperforming A15...With Less Power!!!Linus Torvalds2013/07/12 08:11 AM
                                          Saltwell Outperforming A15...With Less Power!!!bakaneko2013/07/12 09:12 AM
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                                              JIT2013/07/13 04:50 AM
                                                How'd you get this flower symbol as your user name ?anon2013/07/13 08:20 AM
                                                  How'd you get this flower symbol as your user name ?Doug S Ꭳ❂〄☢⚓♜☎♬⚄☠2013/07/13 09:12 AM
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                                    Not reallyAnon2013/07/11 10:21 AM
                                    consistency, pleaseMichael S2013/07/11 10:22 AM
                                      consistency, pleaseLinus Torvalds2013/07/11 10:52 AM
                                        consistency, pleaseMichael S2013/07/11 01:43 PM
                                          consistency, pleaseLinus Torvalds2013/07/11 02:12 PM
                                            consistency, pleaseMark Roulo2013/07/11 02:54 PM
                                              the discussion was about absence of AVX in Silvermont (NT)Michael S2013/07/11 02:59 PM
                                                the discussion was about absence of AVX in SilvermontMark Roulo2013/07/11 03:19 PM
                                                  the discussion was about absence of AVX in SilvermontLinus Torvalds2013/07/12 08:16 AM
                                                    Thank youMark Roulo2013/07/12 08:58 AM
                                                    the discussion was about absence of AVX in Silvermontanon2013/07/12 09:10 AM
                                                      Not really (again)Anon2013/07/12 09:26 AM
                                                        Not really (again)anon2013/07/12 04:40 PM
                                                    the discussion was about absence of AVX in SilvermontLinus Torvalds2013/07/12 09:31 AM
                                                      you are wrong at about 100% of you saidMichael S2013/07/13 10:22 AM
                                                        you are wrong at about 100% of you saidLinus Torvalds2013/07/13 11:08 AM
                                                          you are wrong at about 100% of you saidMichael S2013/07/13 12:13 PM
                                                            you are wrong at about 100% of you saidLinus Torvalds2013/07/13 01:11 PM
                                                            you are wrong at about 100% of you saidvvid2013/07/13 02:20 PM
                                                              you are wrong at about 100% of you saidMichael S2013/07/14 12:38 AM
                                    Saltwell Outperforming A15...With Less Power!!!anon2013/07/11 05:41 PM
                                    Saltwell Outperforming A15...With Less Power!!!bakaneko2013/07/12 02:22 AM
                  Round 2: Baytrail benchmark (yes Antutu!) crushes Snapdragon 800.sammy2013/07/12 10:28 AM
                    Round 2: AnTuTu scores drop dramatically for AtomWilco2013/07/12 10:59 AM
                      Round 2: AnTuTu scores drop dramatically for AtomSteve2013/07/14 07:16 PM
                        Round 2: AnTuTu scores drop dramatically for AtomKlimax2013/07/14 09:59 PM
                        Round 2: AnTuTu scores drop dramatically for AtomDavid Kanter2013/07/15 12:57 PM
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                                  Intel is cheating AnTuTuWilco2013/07/16 02:47 AM
                                    Intel is cheating AnTuTubakaneko2013/07/16 04:50 AM
                                      Intel is cheating AnTuTuWilco2013/07/17 02:33 PM
                                        Intel is cheating AnTuTuKlimax2013/07/17 10:29 PM
                                          Intel is cheating AnTuTunone2013/07/17 10:35 PM
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                                              Intel is cheating AnTuTuanon2013/07/18 01:10 AM
                                                Intel is cheating AnTuTuMichael S2013/07/18 02:39 AM
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                                                    Intel is cheating AnTuTuMichael S2013/07/18 05:44 AM
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                                                  Intel is cheating AnTuTuanon2013/07/18 11:05 AM
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                                  Intel is cheating AnTuTuLinus Torvalds2013/07/16 11:32 AM
                                Intel is cheating AnTuTu2013/07/16 02:16 AM
                                  Intel is cheating AnTuTubakaneko2013/07/16 03:55 AM
                                    Intel is cheating AnTuTuWilco2013/07/17 02:46 PM
                                      Intel is cheating AnTuTubakaneko2013/07/18 01:05 PM
                                      Intel is cheating AnTuTuDavid Kanter2013/07/19 01:31 AM
                          Round 2: AnTuTu scores drop dramatically for Atomanon2013/07/15 03:43 PM
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                          Round 2: AnTuTu scores drop dramatically for AtomGroo2013/07/16 06:35 AM
        ARM at Computexanon2013/06/04 09:43 PM
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