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Can anyone attribute the recent surge in AMD performance to recent hiring blitz or some other shift? I know they were struggling and trying out new things with
by zelon88 7y ago
Can anyone attribute the recent surge in AMD performance to recent hiring blitz or some other shift? I know they were struggling and trying out new things with bulldozer modules and trying to compartmentalize as much as possible. It reminds me of when Intel hired all those Israeli engineers who went back to the PIII design and miniaturized it, gaining performance by throwing away years of work on the P4.
Was there any of this at play recently at AMD?
- cpuguy83 7y agoAMD's apparent velocity is likely due to multiple factors, first and foremost is Intel has essentially been stuck, trying to shrink die sizes (something AMD has essentially outsourced), suffering from shortcuts leading to Spectre/Meltdown and the performance regressions due to patching those, and inability to get their new architecture out the door. All this coupled with really good execution from AMD, new architecture that has turned out to work really well and not really having to deal with Spectre/Meltdown regressions. So yes AMD is doing very well, Intel's current problems makes them look even better. How much of this is hiring and how much is just trucking along? Who knows.
- IshKebab 7y agoAMD chips suffer from Spectre too (which is the hard to fix issue). They didn't really take any fewer "shortcuts" than Intel. And they weren't "shortcuts".
- codeflo 7y agoThat’s highly misleading, and the very careful way that you worded your reply tells me that you know this. Why the obfuscation?
- Gabrielfair 7y agoI am a phd researcher studying linguistics and deception. You mentioned the op was being misleading and communicated an understanding of the op's subversive intentions. Could you help me understand how op was being deceptive and how you knew based on their choice of language? If you don't want to comment publicly and are still interested in helping me you can reach me at: gfair @ uncc.edu
- jdsully 7y agoI'm not OP but it comes from the fact that Spectre is a very specific bug, but is colloquially used to refer to all speculative execution bugs found after as well. So its true that AMD is susceptible to Spectre; However, the mitigations have a much lower effect on performance. Additionally AMD is not susceptible to the multitude of additional speculative execution bugs found in the time since Spectre was first announced.
- IshKebab 7y agoSpectre was used to refer to all speculative execution timing leaks from the very beginning. That's why they called it "Spectre" - because it's going to be hanging over us for a long time.
- IshKebab 7y agoI wasn't obfuscating anything. Spectre is a fundamental flaw that affects Intel and AMD processors. Speculative execution is not really a "shortcut". Intel did make one shortcut but that resulted in Meltdown, which is easy to fix (conceptually anyway - I'm sure it was a lot of work!) Any idea why I've been downvoted so much for saying something that surely everyone here remembers (wasn't that long ago) and is easily verified on Wikipedia: https://en.m.wikipedia.org/wiki/Spectre_(security_vulnerability) https://en.m.wikipedia.org/wiki/Spectre_(security_vulnerabil... > As of 2018, almost every computer system is affected by Spectre, including desktops, laptops, and mobile devices. Specifically, Spectre has been shown to work on Intel, AMD, ARM-based, and IBM processors.
- codeflo 7y agoGiven that others also asked, I'll give a rundown of the discussion: The context of the discussion was cpuguy83's suggestion that compared to AMD, Intel has been "suffering from shortcuts leading to Spectre/Meltdown and the performance regressions due to patching those". cpuguy83's comment was very concise, so let me elaborate that the distinction between Spectre and Meltdown is essential here. Both are security flaws in CPUs that were published at the same time. Spectre is an industry-wide problem that also hit AMD, but "Meltdown" is the result of an Intel-specific implementation choice that I think one might fairly describe as a "shortcut". (Even IshKebab later agrees: https://news.ycombinator.com/item?id=21342048 https://news.ycombinator.com/item?id=21342048) Meltdown was also more immediately dangerous, and the software workarounds that were necessary to mitigate it in existing CPUs cost a lot of performance. Given this context, I'll quote the relevant item from cpuguy83 again and then IshKebab's reply: > cpuguy83: Intel [... has been ...] suffering from shortcuts leading to Spectre/Meltdown and the performance regressions due to patching those. > IshKebab: AMD chips suffer from Spectre too (which is the hard to fix issue). They didn't really take any fewer "shortcuts" than Intel. And they weren't "shortcuts". Note how IshKebab carefully ignores the Meltdown part of cpuguy83's comment to be able to claim that Intel hasn't been doing any worse than AMD, and that there were no shortcuts. For Spectre in the stricter sense, that's technically true. It's not true in the context of the entire Spectre/Meltdown event, which was cpuguy83's argument.
- gen3 7y agoIsn’t the big performance hit because Intel wasn’t checking permissions where they should have? How is that not a shortcut? They skip a step for speed.
- comex 7y agoThat’s Meltdown, not Spectre. Meltdown arguably does fit your description, but AFAIK the cost of checking permissions in the right place is almost zero, so it’s arguably better described as “we never realized it would be dangerous to not check permissions here” than “we skipped the check for performance’s sake”. (AMD processors were not vulnerable to Meltdown.) Spectre, on the other hand, is sort of an inherent flaw of speculative execution (not related to permissions checks). Speculative execution itself is definitely a shortcut, but it’s a shortcut that’s crucial to the performance of all modern high-performance processors, with the result that nobody really knows how to deal with Spectre. Intel was apparently hit harder than AMD by side channel mitigations collectively, apparently because Intel was doing more aggressive speculation – but those mitigations are only partial. Both vendors’ processors are still vulnerable to Spectre attacks even with mitigations applied [1], and that will remain the case even on future processors, for the foreseeable future. [1] https://arxiv.org/abs/1902.05178 https://arxiv.org/abs/1902.05178
- paulmd 7y agoContrary to popular sentiment, Meltdown is also not an Intel-unique bug, it also affected POWER and ARM processors. AMD essentially got lucky on this one - their neural-network based branch predictor is difficult for an attacker to train to follow specific code paths, which is a necessary component of Meltdown/Spectre style attacks. Pretty much every other processor that does speculation is affected. The potential for cache timing to serve as a side-channel leak was not widely appreciated in the industry, although it was theoretically described as far back as the early 90s.
- dodobirdlord 7y agoAbsurd to see this response flagged so heavily when it is correct on every point...
- codeflo 7y agoGiven that I have the highest voted reply and several people asked, I've written a rundown here: https://news.ycombinator.com/item?id=21345820 https://news.ycombinator.com/item?id=21345820 Yes, the response is technically correct. But...
- weare138 7y agoPlus Intel has been such a dominate player for so long they've had no reason to innovate and largely haven't in some time. Their complacency caught up to them.
- zrav 7y agoYes, since Sandy Bridge (2011) each new generation of Intel CPUs brought a single digit percent increase in single-thread performance only.
- alecco 7y agoThe anti-Intel circle jerk has to slow down a bit. Intel management is terrible but their engineers have been delivering amazing features. Did you know nowadays the main performance bottleneck is memory latency? For 8 years Intel has the best LLC around and with a very fancy adaptive replacement algorithm. Also the recent release of 10th gen came with 50% more L1 and 100% more L2, plus AVX-512 with finally a decent subset even on mobile i3 chips. And there are a lot of other important details most people miss.
- username90 7y agoThe fact that Intel has an order of magnitude bigger R&D budget than AMD but still losing on many key metrics means that Intel is either doing a really bad job or AMD is full of geniuses. Nobody is saying that Intel does nothing, but they could have done so much more if they managed it better.
- cpuguy83 7y agoYou have to take into account that Intel is having problems getting their next-gen architecture out the door.... who knows what it will bring good or bad... heck maybe even some of the delay is "oh crap Zen even beats our next-gen". Perahps Intels next-gen is just vaporware and they really have been sitting around raking in the $$$ b/c they could. I'm really not trying to defend Intel (I understand that it may come across that way), just how we look at the situation. Indeed you could be spot on, just that the situation at Intel is likely multi-faceted.
- rumanator 7y ago> AMD's apparent velocity is likely due to multiple factors, first and foremost is Intel has essentially been stuck, trying to shrink die sizes AMD's success has nothing to do with Intel's failure. AMD engineered a beast of a processor architecture that runs circles around the competition at a price that renders competing options obsolete. Ryzen's performance track record would not be any different even if Intel did not sold processors with security problems or succeeded shrinking die sizes. It boggles the mind how some people try to spin AMD's outstanding progress as something that Intel did instead of a collosal technical achievement by AMD.
- cpuguy83 7y agoThat's not what I said at all. I said AMD is doing very well, and they look like they are doing even better because Intel is having problems. I recall an anecdote from an AMD engineer (from some article) "we expected to be competing against Intel's next-gen architecture" (paraphrased).
- georgeburdell 7y agoNot involved at all but I also wonder something similar. It’s like when you have nothing left to lose, there’s more freedom to innovate
- gumby 7y agoAMD has always been strongly marketing driven going all the way back to its founding with Jerry Saunders brought into the team.
- the8472 7y agohttps://en.wikipedia.org/wiki/Jim_Keller_(engineer) https://en.wikipedia.org/wiki/Jim_Keller_(engineer)
- JimmyAustin 7y agoJim Keller [1] is widely credited for a large amount of Zen's success. Interestingly he is now at Intel. [1] https://en.wikipedia.org/wiki/Jim_Keller_(engineer) https://en.wikipedia.org/wiki/Jim_Keller_(engineer)
- baybal2 7y agoYes, he is a very well off man now. He moved to Intel during last transfer season
- agumonkey 7y agoIIRC he went at every important cpu company back to back. Wasn't he part of the Apple soc team too ?
- paulmd 7y agoYes. Designed Alpha for DEC, Designed Athlon/Athlon XP/Athlon 64 for AMD, designed network switches for SiByte/Broadcom, designed Apple's SOCs at PA Semi, designed Zen for AMD, designed AI accelerators at Tesla, now back at Intel. Apart from SiByte/Broadcom pretty much a greatest hits list of disruptive architectures over the last 20 years.
- chocolatebunny 7y agoAren't Broadcom network switching SOC the industry standard?
- kijiki 7y agoYes, but those are fixed function designs like Trident or Tomahawk (yes, they name their switch chips after missiles). When Broadcom uses the term SOC, they mean "Switch on a Chip" to differentiate their single chip designs from older multi chip architectures. SiByte was MIPS-based, more like an NPU than an (Broadcom term) SOC.
- hajile 7y ago
- spamizbad 7y agoI think AMD has always had the talent, but made a bad bet with bulldozer's architecture of two cores sharing a front-end and FPU[1]. I also think desktop software (specifically games) moved faster than some anticipated when it came to taking advantage of multiple cores, causing them to be seem resource starved. [1] At least that's how I think they work. One decode and FPU per pair of integer cores, right?
- moonbug 7y agoBulldozer's failure was really one of market positioning. It would have been much better received if the CMT modules had been presented as a single, dual-threaded core, positioned against an Intel HTed core, rather than as two separate cores.
- wmf 7y agoEven if Bulldozer had been marketed as quad-core it was still losing to Intel quad-cores and it had a larger die.
- zelon88 7y agoNevermind the power consumption. I had an FX9590, which was a 4.7ghz 8-core at 220w. 220 watts!!!
- officeplant 7y agoAnd my R7 1700 pulls up to 230w at 4.1GHZ all core. Some things never change, except vastly more performance per watt.
- paulmd 7y agoWhile I generally agree that CMT threads are not a real "core" (and has never been presented as such by any other company that has explored CMT), the real problem with Bulldozer was a frequency-optimized, deeply pipelined design. AMD literally repeated the exact mistake that Intel did with Netburst. It would never have been good no matter how you positioned it.
- NortySpock 7y agohttps://en.wikipedia.org/wiki/Jim_Keller_(engineer) https://en.wikipedia.org/wiki/Jim_Keller_(engineer) Some say Jim Keller's work at AMD lines up nicely with AMD's resurgence.
- toast0 7y agoHis work also lines up nicely with the DEC Alpha, early Athlon/Opteron, and Apple A4/A5. With no malice, I'm not aware if anything of significance came from his time at Tesla. It will be interesting to see if AMD can keep things going past Zen 3 next year (which is likely to be the end of Keller's direct influence), and also what Intel can do with his guidance, which I would expect to release sometime in 2021-2023.
- smachiz 7y agoHe built their in-house chip chip that's in their v3 self-driving computer, no?
- strangemonad 7y agoI thought that was Pete Bannon https://www.theverge.com/2019/4/24/18514308/tesla-full-self-driving-computer-chip-autonomy-day-specs https://www.theverge.com/2019/4/24/18514308/tesla-full-self-...
- _ph_ 7y agoTesla not long ago presented their impressive in-house neural network processing chip. Quite likely, that Keller was an important contributor to this. So there would be quite some significant outcome from his time at Tesla.
- zokula 7y agoIt was Mike Clark who is the Lead man for Ryzen and Epic designs.
- quotemstr 7y agoBig tech companies generally have tons of talent that they waste on having engineers basically stop each other doing technical things. It's a waste to have smart and expensive people work at cross purposes, but it frequently happens for internal political reasons. Sometimes a company in this situation gets the fear of God put into it and realizes that it actually needs to compete. At this point, all the red tape mysteriously disappears and all the process overhead that very serious people claimed was 'essential' disappears without the sky falling. Consequently, the company can now actually compete, and long-timers within the company who blocked progress for years get embarrassed, sidelined, or fired. This dynamic is the reason competition is essential. Without external force compelling action, every organization trends toward stasis.
- nine_k 7y agoI may suppose that this is a result of several less fortunate iterations (bulldozer, anyone?) which led finally to a machine that checks all interesting boxes. You can't build a new thing right from scratch, but you can market intermediate imperfect results to cover the losses somehow; I suppose that's what AMD did a few years ago. Now they have finally hit the 10, and reap the benefits.
- SkyMarshal 7y agoThat's my sense of it too. A ~decade of tinkering with this modular architectural approach is effectively an evolutionary process, plus perhaps valuable input from a once-a-generation expert like Keller, results in leapfrogging the current state of the art. The key, as you say, was surviving an unpredictable amount of time till the tinkering paid off.
- rbanffy 7y ago> results in leapfrogging the current state of the art. Intel also helped by botching their move to 10 nm.
- gpderetta 7y agoZen Is really a from a scratch design far from a refinement of bulldozer which was a dead end. Instead of experimenting with exotic architectural solutions they built a unexciting but extremely solid design (i.e. the improvements and wins were in the small details, not the overall architecture) and won. This parallels the years that Intel wasted on the dead ends of Netburts or Itanium.
- ahartmetz 7y agoFrom what I read, AMD explicitly chose some details to be close to Intel's, e.g. cache size, size (and existence) of micro-op cache and so on. Software / compilers and Intel CPUs are optimized for each other, so it's best to be similar and a maybe a little better where it makes sense. While that strategly doesn't yield something vastly better than Intel has, AMD really needed something good so it wouldn't go bankrupt. Due to the process situation and a few nice energy-related innovations like clock stretching (allows running at voltages very close to instability), AMD actually did get more power-efficient high core count CPUs.
- newnewpdro 7y agoI've read in multiple places that AMD's resurgence is largely attributable to controversial IP deals and partnerships made with China, providing a struggling AMD with the resources necessary for Zen development. e.g. https://www.wsj.com/articles/amd-to-license-chip-technology-to-china-chip-venture-1461269701 https://www.wsj.com/articles/amd-to-license-chip-technology-... Edit: https://en.wikipedia.org/wiki/AMD%E2%80%93Chinese_joint_venture https://en.wikipedia.org/wiki/AMD%E2%80%93Chinese_joint_vent...
- deleted 7y ago[deleted]
- twotwotwo 7y agoThe internal Intel competitive analysis is not bad here: https://www.techpowerup.com/256842/intel-internal-memo-reveals-that-even-intel-is-impressed-by-amds-progress https://www.techpowerup.com/256842/intel-internal-memo-revea... I don't know about µarch details but a bunch of bigger-picture things have contributed to AMD's run: Spinning off their foundry ops led to AMD getting to use TSMC, who turned out to have a great process node at 7nm. Indirectly, it probably helps that other huge customers mean TSMC can amortize their process development costs across all of them. The chiplet approach with a separate I/O die has various advantages: - The Zen 2 chiplet is identical from the cheapest client CPU to the most expensive server CPU. Surely reduces complexity, and silicon that won't work in a server part might work in a client chip or whatever. - Relatedly, binning 8-core chiplets is way more forgiving than binning huge monolithic CPUs like Intel's doing; with AMD lots of cores and high perf doesn't require a huge, uniformly near-perfect die, just enough chiplets that meet the spec that you can glue together. - The I/O die is on a very mature, probably cheaper GloFo process, which may have made it less costly for AMD to offer interesting features on the I/O side (PCIe 4 and 128 lanes even for the cheapest server part, AES-128 in the memory controller, etc.). Won't happen this gen, but I kind of expect Intel to eventually use some version of chiplets for their larger parts. They're talking about their advanced stacking/packaging tech, so not totally outlandish. Short-term they do have a two-die Cascade Lake mega-CPU planned, but I mean more broadly. One cost of chiplets is in higher DRAM access latencies. AMD's done things to try and mitigate that, including just using lots of L3 cache. From benchmarks it seems to work. The Intel analysis also mentions their shift to higher-margin parts as important. I don't know how critical it is to the story but AMD also did some deals that may've given them resources to invest in their designs, like the GloFo spinoff, the deal to sell Epyc 1 clones in China, and the deals to produce Xbox and Playstation chips. Finally, Intel would ordinarily have their own progress that would make AMD look comparatively worse. But 10nm stalled an incredible amount of time and Intel's post-Skylake core design, Sunny Cove, depended on it.
- sliken 7y agoAMD been executing well on multiple fronts. One big advantage is that AMD divorced themselves from their fab (now global foundries). So when a particular fab fails at a shrink they can just switch. In the 7nm case that means moving from global foundries to TSMC. Additionally they were first to hypertransport (Intel followed with QPI) and knocked it out of the park with chiplets. Having two dies per package was pretty common, even way back at the 66 MHz pentium pro. But HT allows AMD quite a bit of flexibility. They can switch lanes between hypertransport (now updated and called Infinity Fabric) between pci-e and IF. The this helps them on multiple fronts. It decouples the CPU and memory interface and pci-e standards. It raises their yield by using smaller chips. It also allows them to use different processes for different chips, so now the I/O die can use an older process. One big impact is now only does the yield increase, but also the increased number of chips lets AMD amortize their R&D over more dies, and also customize for different produces without having to spend the extra R&D on numerous different dies. The low end desktop/laptops get 2 chips (1 cpu + 1 I/O). Higher end chips get 3 chips (2 cpu + 1 I/O). The high end servers get 9 (8 cpu and 1 I/O). So they can go from under 65 watts and under $200 to over 250 watts and over $5,000 all based on the same chiplets. The AMD first generation Epyc did expose some weaknesses in OS/Applications that didn't like the high variations in latency to main memory and I/O. 4 chips inside a single socket had their own pair of memory channels and would have to use Hypertransport/IF to get to the other 6 memory channels. The design was reasonable, but many apps were NUMA aware and ran poorly. In the second generation AMD moved all memory channels to the I/O chiplet and now the socket is a single NUMA domain and all chiplets see identical latency. The NUMA tweaks, 10-15% improvement in IPC, big improvement on the floating point side, and 1.5 x more cores (depending on the model) means that for many real world codes that AMD Epyc generation 2 chips (rome) are twice as fast at real world codes as the previous generation, which Intel is still trying to match. Meanwhile Intel is still trying to get a Xeon shrink they promised in 2017 working. So generally ability to switch fabs and how well HT/IF works with chiplets caught Intel at a really bad time and for once AMD seems to be actually executing well and producing non-trivial volumes into multiple market segments.