Alder Lake: Fedora 35 and the 12900k

intel has bestowed upon us cpus that are radically different of course we're talking about alder lake 12 900 k and also the i5 i've got that we've got the i7 the i9 and the i5 only had time to do the i5 and i9 so far but this is actually the die layout for alder lake the i9 12 900k to be precise it's 16 cores eight performance cores and eight efficiency cores if you look at how that's actually laid out on the die the performance cores they're big the efficiency cores they're tiny so it's not an homogeneous architecture for the first time i think an x86 history we have performance cores and we have efficiency cores that means a lot for linux [Music] so this is alder lake and this is also alder lake so yeah this is a blown up version of what the cpu die looks looks like and this is actually a pretty convenient prop for helping understand how the breakdown of the cpu is it's a desktop class cpu which means it has an integrated you know gpu there's a there's on-chip graphics capabilities and typically you know linux users have sort of enjoyed this as like the desktop pedestrian sort of cpu it's 16 cores 24 threads which sounds weird but the performance cores are the ones that give you two threads per core the efficiency cores well they're not real big there's not a lot of room for those resources on silicon and they only handle one thread per core the efficiency cores run with an ipc that's roughly equivalent to uh sky lake you can check out the benchmarks if you want to dive in there phronix also did a really nice roundup definitely check that out too for their benchmarks i'm sure their benchmarks will have more in-depth nitty gritty info i want to talk about some of the stumbling blocks and and cool stuff that i ran into with this so yeah efficiency cores basically equivalent to skylake they're tiny that's really impressive the performance cores however are monstrous absolutely monstrous performance if you want to run an interactive desktop and you want your interactive threads to be as insanely fast as possible there is nothing like alder lake in terms of that responsivity responsibility responsiveness response i don't know intel you know they said performance or performance and performance cores efficiency cores but the tense isn't all the same and all the press documentation quietly driving me insane distro support is a little sketchy um so i tried to do most of my testing with fedora 35 because it literally just dropped first on the beta and then i went back literally just a couple hours ago at the time that i'm shooting this to make sure that basically everything still works and everything's still aligned now even though i'm using kernel 5.15 on fedora 35 and you know relatively recent 5.x kernels for most of my testing i still saw a lot of odd problems like uh kernel oopses you know those are non-fatal but it's like hey i can't set this in an msr register or hey i need this specific version of the bios or hey i need this so if you do pick up one of these plan on a day one bios update yeah just don't even bother setting up your machine until you go to the manufacturer's website for your motherboard and download the latest bias i can almost guarantee that whatever you buy in the store or whatever comes from your online retailer is not going to be the latest version of the bios just about guarantee it if you were here for the x299 launch that's feeling a little bit like that a little bit i won't say rushed but for linux users there's some sharp edges real sharp the bottom line is this because there are performance cores and because there are efficiency cores the linux scheduler is not really taking advantage of that yet there's a hardware assist for scheduling built into alder lake something called thread director but we're not there yet on linux we're not there yet with a lot of things turbo boost as far as letting the hardware do turbo boost to a point is working on linux but a lot of the really fancy stuff like the thermal velocity boost that you can kind of enjoy the windows platform not really here to be sure it's not really here on windows 10 either it's really only on windows 11 but as a linux user you're going to have some early adopter attacks here around power utilization and performance and scheduling and consistency now it's kind of ironic though because the efficiency cores promise to make this this the most efficient desktop processor that we've ever seen that idle my linux system which admittedly consisted of a really high-end gpu and a system consuming about 150 watts at idle this is on the the msi z690 platform now msi was very very awesome and supplied the test platform that i used for this the i5 and the i9 testing and i've got no complaints against their motherboard it actually works really well and it's got really good support for linux out of the box in terms of you know x2 advanced programmable in-up interrupt controller support worked correctly uh the io mmu groups were reasonable and the other peripheral support was pretty reasonable this motherboard from msi has a lot of m.2 connectivity and intel actually did do something really awesome with the chipset the z690 is a fantastic desktop chipset they really have done something amazing here they've got eight pci express 4.0 links that's actually dmi 4.0 they call it dmi4 it's not quite pci express it's pci express with some special sauce but we've got a lot of bandwidth between the cpu and the chipset eight pci express four lanes worth the chipset itself can support a large number of pci express 4 and pci express 3 peripherals as well as more usb ports and all that kind of stuff so this msi motherboard has a total of five m.2 ports one of course directly from the cpu the other four through the chipset but with all those pci express lanes from the chipset to the cpu it's very unlikely to bottleneck this has been a very consistent criticism from us since really the days of haswell it's like ah connection to the chipset it's always so anemic z690 finally level one approved it's a very very good chipset connection in terms of other pci express connectivity well we've got 16 lanes of pci express 5. we don't even have any peripherals yet really that'll use pc express 5 apart from some field programmable gate arrays that i use for loopback testing story for that on another day and then we've also got four piece express four lanes from the chipset to the nvme so eight gigabytes per second potentially from our highest the end pc express for nvme and 64 gigabytes per second in each direction on pci express 5. and you may be thinking wait does the pci express bandwidth here rival the main memory bandwidth yes it does and so we've moved from ddr4 to ddr5 ddr4 bumps us from roughly 55-ish gigabytes per second at the top end of memory bandwidth to 75 gigabytes per second it's pretty awesome ddr5 promises to be even more faster than that at some point in the future but right now today the highest in ddr4 and the you know ddr5 is available on the market today the performance is similar it's really close unless you're going for like extreme high frame rate gaming there's not really a lot of advantage for moving to ddr5 at this point today right now in q4 of 2021. that may change in short order with faster ddr5 kits becoming available but right now i'm testing our kingston ddr5 kit to be sure it's nice if you can afford it definitely go for it but if you go ddr4 you're not really missing out on a lot especially on the linux platform another really cool surprise on this platform was the volume management device the intel vmd stuff that's intel's raid stuff at a hardware level that's actually really well supported in the linux kernel it's borrowed from prior generation hardware really the implementation of it so when you set up hardware raid in linux it is a kind of software rate it's like a hardware assist software rate it's not technically correct to call it a soft raid but it does depend on linux md multi-disk for it to do its work but md is smart enough to recognize the intel markers on the hardware and there's hardware assist to assist with the uh raid volumes and the ssds things to help lower the latency through the chipset and blah blah so that actually works well on z690 out of the box with relatively recent kernels and recent distros like ubuntu 20.10 and fedora 34 and fedora 35 which means that if you create an intel raid device for multiple ssds it will be generally picked up and used correctly by the distro there are some edge cases there are a couple of gotchas but generally it works really well and also works really well on other distros with other motherboards really nice to see z69 at least on linux i've got some more testing to do here i used some samsung 963s which you know historically required a v rock module it doesn't seem like that's required on z690 i've got a question in the intel asking is like hey are the raid functions unlocked or do you still need to have a chip but it looks like they're unlocked which is great which means you can use any ssd you want which historically with this you know raid stuff hasn't been the case but the fact that you know linux md will just use it anyway and work fine there you go your mileage may vary now you might be wondering what about iomu gpu pass through and all that kind of stuff that's going to have to come in a future video but i can give you a pretty quick summary for this platform because the cores kind of mismatch and i'm oversimplifying here a lot really but because there's eight performance cores and eight efficiency cores this is really better suited to containerized workloads rather than virtualized workloads you could create a virtual machine where you assign it some performance cores and you assign it some efficiency cores but the virtual machine itself isn't really designed to deal with that because performance cores and efficiency cores in the x86 world is not really something we've had to contend with before so there's a lot of bugs and there's a lot of performance variability it's especially egregious if you're a gamer on linux because linux may schedule your high priority game on the wrong core for the game it's not using the hints provided by thread director it's not really the best experience yet i have a feeling that's going to get fixed not too far after launch so i'm going to set a date about three weeks from launch i'm gonna do a follow-up video with uh you know alder lake three weeks later and i'm gonna revisit some of these points around virtualization and game performance and scheduling because they all kind of go together they all kind of touch the same thing this platform because of the pci express bandwidth does have the potential in the integrated gpu of being a really nice platform where you pass through a real physical gpu the problem is with cpu thread scheduling there's not enough transparency between the kernel virtual machine kvm scheduling and pinning things and actually you know where stuff runs you can actually get really creative with systemd you can tell systemd not to use some of the efficiency cores for this or that or the other and actually just run dedicated processes on the efficiency cores yourself so that most of your user interactive stuff stays on performance cores that actually works really well i'll probably write a recipe for doing that as kind of a stop gap measure and put that on a level one forums of course the problem with that is that you're more like a really high-end eight to 10-ish core desktop processor than something that is truly 16 cores and as we've seen on the benchmarks on windows this really does give you know competing 16 core processors where all the cores are exactly the same a run for its money but i'll tell you that with that virtualization workload when you're using virtual machines and you're passing it through to a virtual machine that you might give you know four cores out of your 16 cores or something like that it's not a great experience not yet anyway and it's really down to uh being able to pin things now you could you could create your virtual machine and say these four cores are always going to come from my eight performance cores and that's fine that works great you can even go so far as to go into the uefi on the msi system and disable your efficiency cores altogether but then you're down to an eight core platform that's not an ideal solution so overall i feel like this is something that we can solve in software and i feel like the solutions are gonna come pretty quick but if you are going to build a system around this for linux know that you're going to have some of those early adopter taxes and that's also why you'll see some performance variability in the benchmarks you might have to run the benchmarks five or six times to see okay we obviously we're running an efficiency course more often than not oh we're obviously running on performance cores more often than not because linux's schedulers there's a lot of them in built in the kernel you can change it you can tweak it you can talk all kinds of fun stuff weren't really built to deal with this at least on on launch day even on uh distros like fedora 35 that just came out like two days ago fedor 35 actually beat the cpus to be launched so we can't blame linux distros because the hardware wasn't out yet but it is an interesting situation you can also get into a philosophical debate why do we need small cores on desktop they plug into a wall we don't care about efficiency on desktop we care about efficiency on mobile we care about maybe efficiency in the data center packing in more compute per watt but on the desktop we don't really care about it well this cpu uses 250 watts flat out this is also maybe something else that linux users may need to keep in mind if you buy the k series cpus you know even if you're not interested in overclocking it's going to run potentially 250 watts all the time and it's a much different performance profile than you'll get on a non-k processor which will only run at 250 watts for a limited amount of time there's this idea of pl1 and pl2 power profiles so that the cpu will run at 250 watts initially and then it'll back off to 125 watts well the k parts are unlocked and not only the k parts unlocked for you to manually specify things they are also designed to be able to run at 250 watts basically all the time that pl2 level basically all the time that's well 241 watts in the case of the 12 900k it's like 152 watts in the case of the i5 which by the way the i5 that's 10 cores it's six performance cores and four efficiency cores and let me tell you for a linux workstation like run-of-the-mill i don't need anything special that is a glorious experience because user interactive processes are all about that single thread speed and it is a very very nice experience let me tell you i just it's uh it's breathtaking how far intel has been able to go even since the 11900k which is you know clocked really high they were really doing everything they could to juice all the performance they could out of the you know perform the architecture and the the silicon and the lithography and all the details and here we are with another processor that's juiced even more and you can enjoy most of that juicing with a physically lower number of cores on the i5 if the 600-ish dollar i9 is too rich for your blood which by the way the pricing on these i think is pretty good too the motherboard pricing is a little variable because some of the lower end motherboards will have trouble running that 12 900k flat out so i've got a lot of hardware on the way uh stay tuned get subscribed look for that i'm going to try to do some coverage if you have any questions or something you want to see in a follow-up video definitely let me know i'm going to list level one that's been a quick look at alder lake for linux users i'm signing out you can find me in the level one forums [Music]

Channel: Level1Linux

Views: 35,678

Keywords: technology, science, design, ux, computers, linux, software, programming, level1, l1, level one, l1Linux, Level1Linux

Id: F4uKLVdqAYQ

Length: 16min 6sec (966 seconds)

Published: Thu Nov 04 2021

Reddit Comments

[u/ForlornWongraven]

Wendel is just a great IT guy.

[u/rockstarfish]

Interested to watch. My guess is intel little big does not play well with linux yet

[u/aoeudhtns]

Why do we need little big on the desktop?

I think a lot of this is about getting little big architectures into x86, period. I think that the desktop market is basically a beta test platform so when they start stuffing this in laptops and servers, they can guarantee best-in-class performance. Or at least have all the functionality there.

Although one thing did confuse me, ARM has had big.LITTLE for ages now. I had assumed that the ability to schedule this was in the kernel. But I guess Linux is either still relying on hardware scheduling in ARM, or it's all locked into the ARM portion of Linux and hasn't been generalized across architectures.

[u/_risho_]

I picked up the final generation of intel's previous architecture because I assumed there would be some issues initially. wendel seems to think that progress is going to be made in a matter of months, but i'm not nearly so optimistic. then again he's also the guy that compiles custom patched kernels and qemu for the sake of doing gpu passthrough. i'm not particularly interested in buying anything from this architecture until it can be expected to work out of the box completely unmodified on a an already officially released and supported distro. i've had more than my fair share of dealing with hardware issues and pifalls on linux. i'm so over that shit. that said i'm super grateful for wendel going out into the weeds and exploring this stuff for us and reporting back. it's super interesting to be sure.

[u/robo_muse]

The Minecraft CPU! . . . single core performance all the way.