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Skylake's Linux power management is dreadful you shouldn't buy until it's fixed
- suprjami 11y agoOK, it's broken and doesn't work. I'm getting over 10 hours battery on a Skylake laptop, but it's broken and doesn't work.
- mjg59 11y agoIntel's documentation says that long-term reliability of the hardware isn't assured in this configuration, so yes, it's broken.
- spoiler 11y agoThis is so frustrating, especially when you buy a $3000+ laptop (which is a lot for a laptop in Croatia) only to have to find this shit out on your own, because it's a very specific thing you need to Google. And it is even more frustrating that people complain it's Linux's fault because it "works fine on Windows" (no it doesn't actually[1]), when hardware vendors suck up to Microsoft and have a "oh yeah whatever" attitude towards linux users most of the time. And then people ask themselves why Linux runs better on "old hardware" because it takes years sometimes for all the shit to be ironed out. Ugh! So annoying. Sorry for useless rant. Edit: Hardware vendor shaming needs to be a thing. Most of the time this types of things go "quietly" and this is why nobody at the "management" level cares. [1]: https://news.ycombinator.com/item?id=11153940 https://news.ycombinator.com/item?id=11153940
- kyrra 11y agoIntel actually provides a lot of code to the Linux kernel. At least as of a year ago they were the top contributor to it: http://www.linuxfoundation.org/news-media/announcements/2015/02/linux-foundation-releases-linux-development-report http://www.linuxfoundation.org/news-media/announcements/2015...
- spoiler 11y agoYes, and that is really great, but it would be even greater if they adequately supported their newer & "consumer-level" (for a lack of better expression) hardware as well.
- nkurz 11y agoSkylake's Linux power management is dreadful you shouldn't buy until it's fixed Why is this phrased as being an issue with Skylake, rather than an issue with Linux? That is, why not "Linux's power management on Skylake is dreadful and you shouldn't install it until it's fixed?" Also, as someone who is running a custom compiled Linux 4.4 on Skylake, what's the best way to check what idle state is being used? Idle stats with 'powertop' shows the majority of idle time being spent in C8-SKL. Is this the same as the PC8 he's talking about?
- mjg59 11y agoIt's an issue with Skylake to the extent that Intel do their own hardware enablement for Linux and just haven't done everything they need to in this case. C8-SKL refers to the C state that an individual core is in - the package C states are listed further to the left in the "Package" column.
- nkurz 11y agoI think the package column is also showing C8, although I'm not familiar with the layout. Here's an example of what I currently see: Package | CPU 0 Powered On 0.0% | POLL 0.0% 0.0 ms C1E-SKL 1.3% | C1E-SKL 0.2% 7.1 ms | C3-SKL 0.0% | C3-SKL 0.0% 0.2 ms RC6pp 0.0% | C6-SKL 0.0% 0.0 ms C7s-SKL 0.0% | C7s-SKL 0.0% 0.0 ms C8-SKL 64.5% | C8-SKL 99.6% 9.5 ms | CPU 1 | POLL 0.0% 0.0 ms | C1E-SKL 0.0% 0.0 ms | | C3-SKL 0.0% 0.0 ms | C6-SKL 0.0% 0.6 ms | C7s-SKL 0.0% 0.0 ms | C8-SKL 100.0% 84.8 ms | ... What would I see if it were properly using C8?
- mjg59 11y agoHm. Which version of Powertop is this? Your output is corrupt - RC6pp is a GPU power state, the package states should all be "PC". The output I have looks like https://gist.github.com/mjg59/c753a7cb868fbbfa83e6060c4e4d0f9d https://gist.github.com/mjg59/c753a7cb868fbbfa83e6060c4e4d0f...
- dsp1234 11y agoNote that several commenters on phoronix[0] are saying that they are not having any problems (along with the commenter on this thread[1]) [0] - https://www.phoronix.com/forums/forum/phoronix/latest-phoronix-articles/865131-well-known-linux-kernel-developer-recommends-against-buying-skylake-systems#post865131 https://www.phoronix.com/forums/forum/phoronix/latest-phoron... [1] - https://news.ycombinator.com/item?id=11492693 https://news.ycombinator.com/item?id=11492693
- mjg59 11y agoYes, the behaviour between desktop and mobile parts is very different on current Intel. You'll only see this on mobile - I'm sorry for not having made that clear.
- TYPE_FASTER 11y agoA few semi-relevant notes: * We've bought multiple Dell XPS 13 laptops with Windows off Amazon because the same spec there was roughly $400-500 cheaper than buying the XPS Developer Edition from the Dell website. * We tried running Linux on a Dell non-XPS Skylake Core i7 laptop and it was having many kernel panics. A quick Googling revealed people with a Skylake chipset having a similar issue. * I noticed just a couple days ago that Dell has updated their XPS Developer Edition laptop to Skylake. One difference I see on the site is it ships with Ubuntu 14.04 SP1. I haven't read much about SP1, other than it looks like it's about a year old. So yeah, I'm still buying XPS laptops with 5th gen chipsets because we've had issues with Skylake.
- chias 11y agoA couple months ago I bought a Dell XPS 13 (signature edition) off of Amazon because it was a few hundred dollars cheaper than buying it from Dell, and installed Linux over it. It's a Skylake machine, and it's been working great. I'm using Debian Testing with the kernel pulled from Sid (necessary to get the wifi working). Powertop output is: Package | Core | CPU 0 CPU 2 | | C0 active 6.7% 3.9% | | POLL 0.1% 0.2 ms 0.0% 0.0 ms | | C1E-SKL 5.5% 0.2 ms 1.3% 0.2 ms C2 (pc2) 9.7% | | C3 (pc3) 2.2% | C3 (cc3) 2.5% | C3-SKL 3.2% 0.3 ms 0.4% 0.2 ms C6 (pc6) 4.1% | C6 (cc6) 7.0% | C6-SKL 8.0% 0.3 ms 8.4% 0.7 ms C7 (pc7) 0.0% | C7 (cc7) 28.7% | C7s-SKL 0.0% 0.1 ms 0.0% 0.7 ms C8 (pc8) 12.1% | | C8-SKL 29.4% 1.9 ms 60.5% 2.3 ms C9 (pc9) 0.0% | | C9-SKL 0.0% 0.0 ms 0.0% 1.3 ms C10 (pc10) 0.0% | | C10-SKL 4.3% 3.6 ms 14.6% 4.1 ms | Core | CPU 1 CPU 3 | | C0 active 5.2% 4.4% | | POLL 0.0% 0.0 ms 0.0% 0.2 ms | | C1E-SKL 1.5% 0.2 ms 1.5% 0.3 ms | | | C3 (cc3) 0.6% | C3-SKL 0.7% 0.2 ms 0.7% 0.2 ms | C6 (cc6) 14.7% | C6-SKL 10.8% 0.7 ms 13.8% 0.8 ms | C7 (cc7) 52.0% | C7s-SKL 0.1% 1.1 ms 0.0% 0.4 ms | | C8-SKL 59.6% 2.1 ms 59.8% 1.8 ms | | C9-SKL 0.0% 0.0 ms 0.0% 0.0 ms | | C10-SKL 9.7% 4.4 ms 8.4% 3.5 ms | GPU | | | | Powered On 13.2% | | RC6 86.8% | | RC6p 0.0% | | RC6pp 0.0% | | | | | | | | | | | As far as I can see, this seems to imply C8 is working fine?
- Animats 11y agoIntel: "Long term reliability cannot be assured unless all the Low-Power Idle States are enabled." Does that mean if you run the CPU too much, it will die quickly? Is there some low limit on time at full power? Electromigration problems, perhaps?
- sliverstorm 11y agoElectromigration That would be my bet. They probably assumed based on typical workloads, a certain percentage of the time, the part would be asleep. Which is generally a reasonable assumption for non-server parts. More sleep means less activity, and less heat (which accelerates EM)
- Animats 11y agoThe desktop Broadwell CPU was supposedly canceled because they had lifespan problems.[1] Overclocking sites report that Skylake processor life suffers badly when overclocking is attempted. Now Intel is effectively saying their CPU is intermittent-duty only. Intel may be having serious problems with electromigration. Is this the limit for CPU speed and transistor size? [1] http://wccftech.com/intel-debating-commercializing-broadwellk-binned-alleges-italian-report/ http://wccftech.com/intel-debating-commercializing-broadwell...
- ggreer 11y agoIntel sells Broadwell Xeons, so if they had an electromigration problem with their 14nm node, they must have fixed it by now. Either that or they're going to recall a ton of server chips.
- tremon 11y agoServer chips are usually equipped with better cooling though, so the problem may not be as acute there. There's also the possibility than Intel is only now finding out the problem with their 14nm process, now that Broadwell has been around for a few years.
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- dman 11y agoFor what its worth Microsoft has struggled with power management on mobile skylake as well - https://www.thurrott.com/mobile/microsoft-surface/62772/microsoft-will-not-fix-power-management-issues-with-new-surface-devices-until-next-year https://www.thurrott.com/mobile/microsoft-surface/62772/micr... . There have been multiple firmware upgrades but if you look at /r/surface on reddit multiple people (myself including) still have issues with power management and sleep on the skylake surface pro 4's.
- rorosaurus 11y agoProblems with wake? I see those sometimes. I haven't seen the rapid battery drain in sleep people talk about (yet). Still, I'm nearly convinced to return my SP4 device due to frustration from these issues.
- dman 11y agoI have the battery drain during sleep problem.
- voltagex_ 11y agoArgh, I probably have this with an XPS 9350 - I wonder if Dell will patch it.
- uto 11y agoInteresting. Could you tell which model you have? I have had very few problems in general on my SP4 i7-16GB model. I've had to reset the device maybe once or twice in the last ~4 months.
- deleted 11y ago[deleted]
- lmm 11y agoDoes that affect the Surface Book too? I just got an i7 Surface Book.
- ikeboy 11y agoI had an HP skylake laptop that overheated last month, then refused to boot, running ubuntu. Had constant issues when resuming from suspend, would sometimes refuse to start, or would lose wifi. Now wondering if it's connected.
- jonotime 11y agoInteresting since I continue to be impressed by my skylake's low power consumption. I built a desktop (arch linux kernel 4.2 - 4.4) a few months back and my killawatt generally show 25-35 watts. Thats way below my old desktop. Its also plenty cool.
- xcasex 11y agoThis reminds me of something.. Oh, right. Baytrail support. that's still lacking as well, and that's also a C-state issue.
- ciokan 11y agohttps://gist.github.com/ciokan/1bb8a5a23e00d1f4344b04d88debc59c https://gist.github.com/ciokan/1bb8a5a23e00d1f4344b04d88debc... Good or bad? Have no idea what C8 should say that's why i'm asking. Dell XPS 9550 ubuntu 16.04
- mjg59 11y agoWell, that's better than most people are seeing - getting deeper than PC6 may involve some graphical things. So the question now is why you have such different results to me. Can you paste the output of sudo lspci -vvv somewhere, along with cat /sys/devices/virtual/dmi/id/bios_version ?
- ciokan 11y agolspci: https://gist.github.com/ciokan/9b0c9b310ecb62b2b2d2cdeacb5f8d18 https://gist.github.com/ciokan/9b0c9b310ecb62b2b2d2cdeacb5f8... bios_version: 01.01.15
- mjg59 11y agoThanks, I'll try to replicate your PCI configuration and see if I can trigger any behavioural changes.
- shadeslayer 11y agoI think I'm seeing a similar usage on my 9550 here https://gist.github.com/shadeslayer/4184b49505d817a9a60d5b0a2ee83513 https://gist.github.com/shadeslayer/4184b49505d817a9a60d5b0a...
- mjg59 11y agoAh - is this a quad-core CPU? Interestingly there does seem to be a pattern building up here, which is that it's more SKU specific than I previously thought - it now looks like it's limited to the S and U parts, which are paired with the Sunrise Point-LP PCH. CPUs that are using Sunrise Point-H appear to work more as expected.
- speeder 11y agoI am planning in buying a 4690K LOTS of people keep nagging me that I should go for a Skylake instead, just because it is "newer" and "better because it is new" I really don't understand that logic. Beside the thing pointed in the article, Skylake has other problems: Win7 don't work properly in it (and Win7 is the last Windows to emulate old DirectX versions correctly on Windows itself). Skylake wasn't design to support analog video at all, something that is still common in third world countries, specially as people keep using old monitors that never break, and are frequently superior to almost all reasonably priced new monitors. Skylake doesn't support OSX (and there are people with reasons to want that). Skylake uses DDR4, that in third world might not be even available for sale, or might have some insane prices (2, 3 times the DDR3 price). Skylake has a couple bugs, and more might pop up in the future. except in US and maybe some EU countries, the price to build a Skylake system is higher than the speed benefit it gives compared to Haswell (usually at most 10%, frequently less...). EDIT: I would also like to point out that Devil Canyons has been reported to work with DDR3 up to 2666 with no issue, some mobos allow Devil Canyons to go up to DDR3 2800 without erroring or being unstable. The thing is, those DDR3 can ALSO reach much lower latency than similar bandwidth DDR4, the few DDR3 vs DDR4 benchmarks done so far, show that usually there is no difference, and when there IS a difference, is usually DDR3 winning.
- TD-Linux 11y agoEven in the US, it doesn't really make sense. Especially with the Xeon parts. You do get a much nicer integrated GPU though, if you use that.
- rz2k 11y agoWill the inclusion of HEVC/H.265 decoding in the integrated graphics be beneficial? On an older MacBook Pro I have with Intel HD Graphics 3000, the fans go beserk on video that my iPad handles with passive cooling without even becoming warm. I can imagine the codecs used on everything you encounter on regular sites will quickly begin to expect optimizations built into Skylake.
- cmurf 11y agoYeah why is that? My Macbook goes nuts like a hair dryer on full when playing a youtube video, where the giant ipad with the same dimension and resolution video is all yawn.
- bb85 11y agoAnecdotal, but I've been running Ubuntu 15.10 for a few months on a Dell XPS 15 (9550), and with kernel 4.4 everything works flawlessly. When idling, power consumption is 8W, and powertop shows 30% C8 and 70% C10.
- ggreer 11y agoHmm... 8 watts sounds extremely high to me. My Broadwell laptop uses less than 3 watts when idle, and most of that is the display. Even my old Ivy Bridge MacBook Air from 2012 idles at 5W. Is there some peripheral responsible for the higher idle on your system? Maybe a hard disk or dedicated GPU? I'm curious about what's causing the difference. CPU/GPU power usage: (≈1W) http://geoff.greer.fm/photos/screenshots/Screen%20Shot%202016-04-13%20at%2020.05.54.png http://geoff.greer.fm/photos/screenshots/Screen%20Shot%20201... Total power usage: (2.9W) http://geoff.greer.fm/photos/screenshots/Screen%20Shot%202016-04-13%20at%2020.07.33.png http://geoff.greer.fm/photos/screenshots/Screen%20Shot%20201...
- bb85 11y agoYou were right! I barely use it on battery so I never investigated. I installed tlp and system went down to 5.5W idle with normal programs open. On fresh boot as low as 4.9W. Turning the screen off shaves 2.5W, and disabling the wireless card saves ~1W. I suspect the SSD + HDD are making part of the difference.
- hacknat 11y agoI can personally confirm this. I bought a brand new Dell XPS 15 with Skylake (i7) in December. I installed Linux on it (kernel 4.3), and it has been a power management nightmare from day 1. I've only ever gotten 2 hours from the battery. I just sent it in because it powercycles at random now, never making it past the Dell splash screen anymore. When I run the hardware diagnostics, sans hard-drive, it dies in the middle of one of the processor tests. Other people have been pointing out that Windows is struggling with Skylake as well, and I've heard the same. Skylake was touted by Intel as being one of their proudest achievements in power management to date. My guess is that their changes were so drastic that the software didn't keep up. Edit: I do have an NVMe hard drive, which does seem to cause some issues, for reasons passing understanding.
- DanGarcia595 11y agoThis is weird because I was reading a thread on Ubuntu forums about 4.3 problems and I've just stayed on 4.2 with 15.10 with no power management issues. Power consumption is criminal though getting 1.8 hours average at full charge and low brightness.
- 0X1A 11y agoI have this exact machine with an i7 and do not get anywhere as low as 2 hours. Do you have bumblebee installed? It sounds like you might have the dedicated graphics runnign at all times, which is the case if you don't have e bumblebee + bbswitch installed.
- dnlrn 11y agoThis depends on the distribution. Fedora for example has GPU switching using PRIME working fairly well and automatically disabled the dGPU by default.
- 0X1A 11y agoWasn't aware of that, though the current performance of nouveau is pretty horrendous. At least for newer cards. It's a bit unfortunate but to essentially have a working card you must have the proprietary drivers installed.
- openfuture 11y agoThis is literally the best timing ever. I was going to place the order for my XPS 13 yesterday but ran into some banking trouble. Then on my way to the bank today I was browsing HackerNews on my phone and now I'm conflicted if I should go through with the purchase or try to find the older model. Does anyone have a reasonable guesstimate as to how likely it is that this gets fixed, because it sounds to me (from this thread) that there is a flaw in the design of the chip and this won't be fixed so easily.
- _Codemonkeyism 11y agoOr the worst, I've ordered a XPS13 some days ago ;-)
- blinkingled 11y agoI guess with all the pressures and cost cuts in QA you'd be better off sticking to Haswell Gen machine for next few years. Which are perfectly fine by the way - Haswell Xeons for your workstation and anything around the i7-4xxx for your laptop will do you fairly well for next 3 years or whatever it takes for Intel to put out a power efficient, stable and well supported part.
- csense 11y agoI was thinking of going AMD for my next system. This post solidifies that decision. Hopefully when their next-gen arch is released [1] it won't be as buggy as Intel's -- which seems like a fairly low bar. [1] https://en.wikipedia.org/wiki/Zen_%28microarchitecture%29 https://en.wikipedia.org/wiki/Zen_%28microarchitecture%29
- 8draco8 11y agoI've just build AMD system for myself based on FX 8320 and so far I love it. I am developer and I am constantly running multiple applications (http server, db, multiple chrome tabs) which are using multiple cores. FX series also supports VT and many other features http://cpuboss.com/cpu/AMD-FX-8320 http://cpuboss.com/cpu/AMD-FX-8320 on top of that usually mobos are supporting 32/64GB RAM even in cheaper boards, and it's enough for casual gaming, not bad for used £90 CPU with CM Hyper 212 EVO cooler
- lllllll 11y agoI got my Asus UX303UA(which won over the dell xps13 option) - i7-u6500 last week. I installed Linux Mint(MATE edition, though I use mainly i3wm). After upgrading to kernel 4.5 I get 8-9h of battery with normal use ( Vim, firefox several tabs, rails/node/redis/postgres server running...), even longer if I'm on-off the computer. I'm really happy with it so far. Besides, I could add +4GB RAM and replace sata HDD with SSD.
- MrQuincle 11y agoSeems a bit exaggerated. I now have a Yoga 900 running 4.4.0-18-generic. It's fine to work through the entire day (6 hours). The only thing that's still causing hiccups is the combination of Wifi and Bluetooth on the same chip which doesn't play nice if I for example stream spotify to my bluetooth speakers. However, that has nothing to do with Skylake.