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The IBM POWER8 Review: Challenging the Intel Xeon
- Quequau 11y agoI'd be a lot more excited about this if they were more accessible. I can barely justify an upgrade to whitebox Intel Xeon servers and there's just no way I could rationalize the prices that IBM demands.
- deleted 11y ago[deleted]
- valarauca1 11y agoBenchmarks sound like their fighting hardware frequency throttling more then actually benchmarking the chips. One big issue to point out: >Floating Point: NAMD GCC sucks at automatic hardware vectorization. So does the LLVM. Really the only time you can count on getting automatic hardware vectorization is if you shell out for the ICC AND write your code in Fortran. I'm gonna bet they didn't vectorized a goddamn thing, but we can't inspect anand's binary so we'll never know. The results are still likely correct, but IBM should have lost by a smaller margin. TL;DR POWER8 is fun but costs 5k more then Xeon per rack mount and uses about 2x the power usage for 10% less performance on generalized work loads. But can pull off 10-15% more performance on _some specialized_ workloads. So meh?
- vonmoltke 11y agoMy experience has been that icc (the C compiler) does a very good job of auto-vectorization. xlc does as well, provided you avoid the horribly misdesigned POWER6 architecture. I agree that gcc sucks for this; we didn't have LLVM last time I was doing this kind of work, so I can't comment on that.
- valarauca1 11y agoLLVM is about on par with the GCC. You just keep moving variables around it decides the moons of Jupiter are properly positioned to vectorize your code. System intrinsics are always your best bet, just really annoying.
- vonmoltke 11y agoWe ended up doing some hand-rolled vectorization that way on the POWER7, because SIMD only really worked well if the data was aligned with the SIMD register width. Intel fixed that problem with a relatively low-cost unaligned load instruction.
- CyberDildonics 11y agoIf you want to really use SIMD units (on x86) check out ISPC. I recommend writing small functions in it that work over large chunks of memory so that SIMD can run at full speed with good cache locality. This ends up being -very- fast.
- valarauca1 11y agoLink for the lazy: https://github.com/ispc/ispc/ https://github.com/ispc/ispc/
- spooningtamarin 11y ago#pragma omp simd collapse(N) works for me almost every time.
- rwmj 11y agoI use POWER8 hardware at Red Hat (supplied by IBM[1]) and it certainly does rock. It helps that I don't have to pay the electricity bills. I just wish the hardware was more available. There is precisely one, barely affordable, non-IBM POWER8 system available to buy[2] (if you have $3-4k burning a hole in your pocket). Where are the development boards? [1] http://research.redhat.com/powerlinux-openpower-development-hosting/ http://research.redhat.com/powerlinux-openpower-development-... [2] http://www.tyan.com/campaign/openpower/ http://www.tyan.com/campaign/openpower/
- asb 11y agoOVH had Power8 available on a per-hour basis through their RunAbove brand for a while, but it seems that experiment was retired.
- justincormack 11y agoOh has that stopped? IBM has them for free if you sign up as a partner, but the OVH service has pretty convenient.
- ju-st 11y agoOnline.net still offers a Power8 server; 1500€ monthly though: https://www.online.net/en/dedicated-server/dedibox-power8 https://www.online.net/en/dedicated-server/dedibox-power8
- thoughtpolice 11y agoThat's unfortunate. RunAbove was very nice and gave us one last year for Haskell.org (so we could port to PPC64le), and our instance is still running well (176 cores/48GB of RAM or so), but I can confirm I can't spin up any new instances. That's a shame, they're excellent machines... I guess we'll have to find another sponsor soon.
- scholia 11y agoCan I assume you're not paying $449,600 for the IBM OS and $424,320 for 3 years of software maintenance?
- notjustanymike 11y agoIBM really needs to hire a professional designer for their slides. That deck is straight out of a 6th grade science fair.
- tychuz 11y agoDid they really used Comic Sans?.. With that yellow discount star sign?.. What. the. hell.
- notjustanymike 11y agoIt's ok guys. It's just our high-power server CPU architecture. Totally cool to slap a yellow star sticker with misaligned text on it. I'm not sure if that's comic sans or a knockoff. Also I just love the teal bevel and big bank bag of cash. And the stock icons for checkmark, arrow, and question mark. And the complete and total misalignment of all the text. Goodness grief.
- notjustanymike 11y agoOh god, even the copywriting is awful. This is a master class in what not to do. Someone give this designer a government job already!
- antod 11y agoNo No No - you are totally missing the point. The design language used in those slides has been iteratively refined over decades and exhaustively A/B tested. It has many years of psychometric analysis applied to make it one of the most powerful sales tools in the world. To win over enterprise PHBs, you need to make them think that you are one of them. That you understand and empathise with them deeply. That you speak their language, and that you are part of their culture. What better way to do that than to give them a powerpoint presentation that looks just like the ones they give each other. That shows that you are already part of their world, and that you are worthy of the key to the executive washroom.
- AnthonyMouse 11y agoPOWER/PowerPC is the same architecture that Apple once used in the Macintosh, so if you want to play with Linux on a PowerPC machine they can be had for almost nothing on the used market. There are really only two models worth having, at opposite ends of the spectrum: The PowerMac G5 (64-bit, based on POWER4) was the fastest available but they're enormous and power hungry. At the other end, the G4 mini is much smaller and more efficient but 32-bit and not as fast.
- jhallenworld 11y agoLong ago I bought a first generation (G3) iMac and ran Yellow Dog Linux for this very reason. It worked fine: $200 for a PowerPC target system.
- ajross 11y agoThis is true, but honestly no one is really interested in playing with the POWER ISA, which for most purposes is Just Another 90's RISC Box. The thing drawing clicks here is the question of whether or not the specific POWER8 architecture can beat contemporary Intel (which means Haswell right now, as Broadwell doesn't have a high performance Xeon variant) architecture in some regimes. And... it kinda doesn't.
- kpil 11y agoI think that apple figured out a long time ago that the price performance would never be as good, and that pure performance would be on par - at best. Since then it has all been about making it look good for enterprise goons. Consolidating and vertical scaling and all that. And poor buggers that end up with high cpu steal and poor performance because a new box is just unimaginably expensive when you have filled the existing system.
- justincormack 11y ago32 bit is not worth having, nothing modern supports it. The G5 was supported with Fedora until recently but alas support was dropped. Also the newer Power distros are the new ppc64le flavour, which is a slightly different ABI and little endian but the G5 is not alas dual endian so does not support it. But they are cheap and quiet and mine has been running reliably, although I might install FreeBSD on it next as that has ongoing support.
- chkuendig 11y agosingle-page link: http://www.anandtech.com/print/9567/the-power-8-review-challenging-the-intel-xeon- http://www.anandtech.com/print/9567/the-power-8-review-chall...
- apaprocki 11y agoNow if only they ran the same benchmarks on a 64-core 4.3ghz POWER8... If your workload scales better on larger boxes, it can be pretty attractive.
- power8scale 11y agoNobody's workload scales better on bigger core boxes without some serious attention to contention and lock avoidance.
- deleted 11y ago[deleted]
- transfire 11y agoDamn IBM, just cut your price in half (including those CDIMMs), and destroy these Xeon monkeys. Why are you being so coy?
- twoodfin 11y agoI don't think IBM wants customers that would buy Power 8 were it not for the price premium over roughly equivalent Xeons. The customers they want will be writing much, much larger checks for services and support.
- scythe 11y agoI've wondered something: MIPS and ARM have both made inroads in the low-power market, supposedly because RISC supports power-efficiency (x86 microcodes notwithstanding), but POWER has always been described as less power-efficient than x86 or other architectures. What makes POWER need so much... uh, power?
- yuhong 11y agoI think they are just designing for a different market. That is part of why Apple ditched PowerPC I think.
- aidenn0 11y agoIntel had a huge process advantage over Freescale when Apple ditched PowerPC. PA-semi proved it was possible to make power-efficient cores (i.e. the PA6T, which everyone assumed Apple was going to use in their next line before the Intel transition was announced). also as a completely unrelated side-note, the number of processor lines started by Dobberpuhl is crazy: Dec Alpha StrongARM (Became X-Scale), what is now the Broadcom MIPS SoCs. Apple picked him up via an acqui-hire, but he retired the following year.
- aidenn0 11y agoAt the high-end, the power-costs of ISA are negligible. Even at laptop levels of power consumption it's barely noticeable. Once an Intel chip has decoded the instructions to uOps, it is mostly on an even playing-field with RISC chips. Also, to be pedantic, POWER is very much not RISC; the only thing it really has in common with RISC is fixed-length instruction encoding (though simpler instruction decoding is an advantage at really low powers).
- Nelson69 11y agoWhat's non-RISC about POWER? IBM's power consumption is probably mostly because they've never put the processors into energy sensitive applications. More importantly, they are sold because of some benchmarks and extreme reliability.
- RexRollman 11y agoPOWER, OS/2, and The Thinkpad has convinced me that IBM just doesn't make the most of what they create.
- rdtsc 11y ago> POWER, OS/2, and The Thinkpad has convinced me that IBM just doesn't make the most of what they create. They are all kind of different. I used to use Thinkpads and I hated IBM for selling it. But from their point of view it was the absolute right thing to do. High end consumer laptops are dominated by Apple (heck IBM is buying Apple and giving them to all their workers, something like 300K Mac Book Pro's). Everything else is racing to the bottom with thinner and thinner margins. Windows running laptops have to compete with Asus and friends and the money just wasn't there. Not sure about OS/2 much, don't remember the history. But with POWER, IBM has kind of started to turn around in the last few years. At some point in the past they have made an explicit choice to not play in the consumer market. Heck, there used to be IBM stores, you'd walk in and buy IBM products like you go to an Apple store now. But they decided they don't want to play in that market (or better or for worse). We'll still see how it ends up working out. So far it still stays in business after hundreds of years, maybe it just luck or there is something to its business approach. (Fun fact, it used to sell cheese slicers and time tracking devices as well at some point).
- yuhong 11y agoThat OS/2 2.0 fiasco is actually my favorite topic, with MS screwing up and later attacking it too.
- epc 11y agoOS/2: decent OS, ahead of Windows for awhile, but IBM was never going to go to the mattresses enough to get it the install base it would need to compete with Windows. IBM's dysfunctional PC division didn't help. It would have been nice if IBM kept OS/2 up as a specialty operating system, but I think the overhead costs were too much and Gerstner was, by 1996-1997, very much in a kill-anything-that-isn't profitable mode. Prior to Gerstner, IBM had a variety of esoteric products which were solely designed as loss leaders, never earned a profit, and relied on subsidies by other parts of the company to stay alive. Post 1993, really starting in 1994-1995 these got killed off or sold off, rapidly. It wasn't enough to break even, one number I recall being thrown around was that we had to get to a 12% Expense-to-Revenue ratio, ignoring SG&A which was a corporate-wide number. Growth products, products in new markets were exempted entirely or given better targets, but old-line products were held to this magical 12% ratio (I was in the mainframe division at the time, which was grotesquely profitable and even today subsidizes much of the rest of IBM).
- 1amzave 11y agoWhy are they using MIPS as a metric for comparing integer CPU performance? When you're looking at two different compiler backends targeting two (very) different ISAs, it seems pretty thoroughly uninformative.
- blt 11y agoIn benchmarks MIPS usually means "we arbitrarily say that reference machine X runs this benchmark at Y MIPS". Then, for a different machine Z, Z_MIPS = Y * (X_TIME / Z_TIME). For example, the 7zip benchmark used in this article is "normalized with results of Intel Core 2 CPU" [1], or the famous Dhrystone integer benchmark's "VAX MIPS" [2]. Still I agree it's weird terminology. It would make more sense to use the true units of the benchmark, or just say "performance relative to reference machine". [1] http://www.7-cpu.com/ http://www.7-cpu.com/ [2] https://en.wikipedia.org/wiki/Dhrystone https://en.wikipedia.org/wiki/Dhrystone
- ternaryoperator 11y agoMainframes have traditionally used MIPS in their benchmarks.
- iheartmemcache 11y agoYep, with you 100%. Anandtech (especially Anand himself) usually does pretty rigorous benchmarks but this is either a poorly executed comparison or intentionally biased towards POWER8 (and I say this as POWER fan and former IBMer). I'm really let down by this review. Another HNer went into detail as to why the comparison is flawed but basically when you compile with a compiler made by the chip designer, especially for numerical computation, the performance is almost definitely going to slant towards that direction. GCC and Clang have to focus on dozens and dozens of backends. Anandtech has more than enough money to spend 1k for an ICC license.