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Intel's New Chimera: Alder Lake

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Re: Intel's New Chimera: Alder Lake

#241

Post by urthor »

kouteiheika wrote: post #16

Personally I don't really see a point in having a hybrid architecture like this unless it'll lead to massively increased core counts, and so far it doesn't look like it does. AMD still beats Intel in both core counts and power efficiency, and they're only using P cores so... what's the point of having E cores? But maybe that's just because it's a first generation technology for Intel? I hope things improve in the fut…

It's because Intel is behind in process nodes (transistor density) and chiplet technology.

Once Intel is matching AMD for density, Intel will be able to jam far more small cores into a multi chip architecture than AMD will with just "big" cores.

Big/Little is a very important step forward towards core density (and idle power consumption, switching off big cores under load is a huge saver in laptop power usage).

Re: Intel's New Chimera: Alder Lake

#242

Post by urthor »

Klasiaster wrote: post #135
Traster wrote: post #80

You get a bunch of smart hardware guys into a room, they design this funky exotic architecture. Then the software goes "Allocate these threads to whatever is idle" and suddenly you've completely lost any possible advantage and are thrashing around with no idea what you're doing. The big-little architecture from Apple was accompanied by software that basically handles that for you. From what I heard there were similar…

So true, my experience with the BIG.little ARM platform and a regular Linux kernel is that you always end up with the wrong scheduling and the system underperforms because it uses the little CPU for a compute-intensive single-thread task… I'll just avoid these kind of systems.

"What Andy giveth, Bill Taketh away."

Big little is fundamentally the correct architecture. It's not Intel's fault that the software guys making the Linux Kernel haven't fully supported heterogeneous yet.

In the long term, it'll be the optimal call for so many workloads. Thousands of server and laptop workloads care only about performance per watt, not peak single thread.

Re: Intel's New Chimera: Alder Lake

#243

Post by PartiallyTyped »

leetcrew wrote: post #215
rbanffy wrote: post #146

Earlier quoted context omitted.

If that’s the game we want to play, there’s always POWER to show what you can pull off with an unlimited power (no pun intended) budget.

not really. for whatever reason, ryzen cpus have very little headroom for overclocking. no matter how much you increase the voltage, you're not gonna get much more performance. intel has increasingly pushed the limits of their designs over the last few generations, but you can usually get more performance with aggressive voltage settings and beefy cooling.

Ryzen CPUs are limited when it comes to overclocking due to the infinity fabric as that needs to be stable and in sync with RAM.

Re: Intel's New Chimera: Alder Lake

#244

Post by vintermann »

hallway_monitor wrote: post #141
willis936 wrote: post #105

Earlier quoted context omitted.

Sure chat apps and video playback are light, but what isn't is browsing the web. Web browsing has become a heavy task. If you tried to install a browser and then use it today on a core 2 duo, you'd have a very bad time. And everyone browses the web, usually quite a bit.

Does it seem strange to anyone that this might be the case, that web browsing is more resource intensive than streaming and playing video? If true, is it because everyone builds SPAs for everything using heavy frameworks like angular and react?

If so, you'd expect boot times to not be affected. They are in my experience. I don't think SPAs are the culprit here.

Re: Intel's New Chimera: Alder Lake

#245

Post by vintermann »

ntoskrnl wrote: post #158
paulmd wrote: post #69

Earlier quoted context omitted.

It’s also not very intensive, especially since video decode usually runs on the GPU. (Or it should - browsers are not always very good about this but the tools are there, they just don’t want to pay licensing fees to use them.) I always cringe a bit when people insist they need 6 cores “so they can have discord and Spotify open while they game”. People don’t generally have a very good intuitive sense of just how litt…

> I always cringe a bit when people insist they need 6 cores “so they can have discord and Spotify open while they game”. I mean, they're not wrong. I have Discord sitting open at the login screen and it's burning 10% of a core. Run a few Electron apps and your core2duo suddenly becomes a core1uno. > Playing a video and writing a document Using what? VLC + notepad, or Chrome + YouTube + Google Docs? There's a huge di…

I don't think Spotify will ban you for optional clients. Other clients are the whole point of their API. There's a bunch of rules you need to follow (largely about attribution) but I think at worst the dev will get their API key revoked - users should be perfectly safe.

Re: Intel's New Chimera: Alder Lake

#246

Post by rocqua »

epsilon_greedy wrote: post #182
Traster wrote: post #80

You get a bunch of smart hardware guys into a room, they design this funky exotic architecture. Then the software goes "Allocate these threads to whatever is idle" and suddenly you've completely lost any possible advantage and are thrashing around with no idea what you're doing. The big-little architecture from Apple was accompanied by software that basically handles that for you. From what I heard there were similar…

As part of alder lake intel includes thread director which handles thread dispatch via hardware and software, I believe. The main downside as far as I know is you have to run a very recent kernel to have access to this.

Thread director gives hints to the scheduler I believe. Its up to the OS to actually use those hints.

Re: Intel's New Chimera: Alder Lake

#247

Post by Traster »

urthor wrote: post #242
Klasiaster wrote: post #135

Earlier quoted context omitted.

So true, my experience with the BIG.little ARM platform and a regular Linux kernel is that you always end up with the wrong scheduling and the system underperforms because it uses the little CPU for a compute-intensive single-thread task… I'll just avoid these kind of systems.

"What Andy giveth, Bill Taketh away." Big little is fundamentally the correct architecture. It's not Intel's fault that the software guys making the Linux Kernel haven't fully supported heterogeneous yet. In the long term, it'll be the optimal call for so many workloads. Thousands of server and laptop workloads care only about performance per watt, not peak single thread.

It's true that the software kills the theoretical performance that the hardware makes available. But I actually think this is an indictment of hardware not software engineers. It's basically "We've created this incredibly difficult problem for you, good luck" from the hardware engineers. How the hell is the OS meant to know whether this thread is going to turn out to be a rendering operation or a logging thread?

With these architectures I think often what the management should really look at is: "We currently employ 100 hardware engineers, and 30 software engineers, with this architecture, we're going to need 50 hardware engineers and 500 software engineers. Do we still think this is the right call?"

Re: Intel's New Chimera: Alder Lake

#248

Post by throwaway0x7E6 »

rocqua wrote: post #70
throwaway0x7E6 wrote: post #6

I feel that P and E split requires putting an asterisk next to the core count. it is dishonest to sell a CPU with N fully featured cores and M gimped cores as a CPU with N+M cores

That is indeed how they are marketed. Either as 8+4core or 8p4ecore. I have only seen the 8+8core referred to as a 16 core machine once. And it was Apple making a comparison to Intel and calling Intel's cpu a 16 core.

oh yeah, I looked it up, you are right. I didn't notice that before

Re: Intel's New Chimera: Alder Lake

#249

Post by pohl »

zaptrem wrote: post #227
pohl wrote: post #163

Earlier quoted context omitted.

True, and not just the system software, but the larger software ecosystem as well. Apple paved the way for the M1 by years and years of goading developers to be honest with themselves about what QoS priorities they really need on their DispatchQueues, and now there are plenty of threads explicitly marking themselves as being good candidates for running on the E cores.

How did Apple do that? I've seen the documentation while building stuff with Xcode but I never saw anything that would have actually forced my app to behave (outside of iOS).

It sounds like you're not asking about technical enforcement — as opposed to prodding, which is what I was talking about. You're right, though, they do also apply pressure through technical means. They did this at design time, by thinking through what the default QoS will be when it is left unspecified.

Re: Intel's New Chimera: Alder Lake

#250

Post by kingforaday »

ntoskrnl wrote: post #158
paulmd wrote: post #69

Earlier quoted context omitted.

It’s also not very intensive, especially since video decode usually runs on the GPU. (Or it should - browsers are not always very good about this but the tools are there, they just don’t want to pay licensing fees to use them.) I always cringe a bit when people insist they need 6 cores “so they can have discord and Spotify open while they game”. People don’t generally have a very good intuitive sense of just how litt…

> I always cringe a bit when people insist they need 6 cores “so they can have discord and Spotify open while they game”. I mean, they're not wrong. I have Discord sitting open at the login screen and it's burning 10% of a core. Run a few Electron apps and your core2duo suddenly becomes a core1uno. > Playing a video and writing a document Using what? VLC + notepad, or Chrome + YouTube + Google Docs? There's a huge di…

People forget about manually setting processor affinity. Requires manual intervention but allows you to account for that simple software.

I posted this comment here because I also appreciate your name.

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