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Intel's New Chimera: Alder Lake

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Re: Intel's New Chimera: Alder Lake

#221

Post by ntoskrnl »

paulmd wrote: post #199
ntoskrnl wrote: post #158

Earlier quoted context omitted.

> 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 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. That is what I said about “people look at the measurement at the desktop and freak out about single-digit utilization without even realizing their processor is sitting in the lowest frequency state”. Is your processor even boosting all its…

I ran a quick `while true {}` in the background. It used 7B cycles per second (twice the clock speed for some reason?), while Discord used about 700M. Discord does drop lower if I minimize the window. But still, thousands of context switches per second, while completely logged out. I have no idea what it could be doing.

You're right that I'm probably not benchmarking rigorously enough. But people don't care about any of this stuff. They care about "my FPS gets lower when Discord is open, pls fix". And they don't want to micromanage CPU usage either. Make sure you minimize Discord after starting the call, make sure you close that gmail tab during the game then open it back up when you're done so you don't miss notifications? No thanks. I'd rather just pay for a few more cores.

I guess what triggered me is you saying you cringe at the end users. They don't deserve that. They just want the stuff they buy to work reliably. And if they need a bunch of extra headroom for that to happen, well, that's just the sorry state of the industry. If you must cringe at someone, direct your cringe at developers.

Re: Intel's New Chimera: Alder Lake

#222

Post by GeekyBear »

em500 wrote: post #37
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…

The top Alder Lake desktop CPU has 16-cores, 8P+8E, compared to 8P in the 11-th gen. The E cores get around half the performance of the P cores, so the 8P+8E is get roughly the performance of a hypothetical 12P+0E CPU. The very high core parts are reserved for Xeon (a 56 core Alder Lake Xeon has been leaked, but I think the P/E split is still unknown). What people need to realize is that a P cores takes around 4 time…

> What people need to realize is that a P cores takes around 4 times the die area/transistors of an E core, and use probably 3 to 4 times the power of an E core, but performance is only around double that of an E core... (Btw, these ratios are pretty similar as those for the Firestorm/Icestorm cores in Apple's M1.)

Apple's strategy with their in house chips has always involved optimizing for performance and power draw, and not so much for die area. They throw execution hardware at the problem and run the clocks slower for power efficiency.

For instance, going back to the 2012 A5x:

>the A5X is approximately 2x the size of NVIDIA's Tegra 3, and even larger than a dual-core Sandy Bridge desktop CPU

While it's technically possible for Apple to have ramped up CPU clocks in pursuit of higher performance, Apple has traditionally been very conservative on CPU clock frequency. Higher clocks require higher voltages (especially on the same process node), which result in an exponential increase in power consumption.

https://www.anandtech.com/show/5688/apple-ipad-2012-review/1...

Caring less about die area makes sense when you are selling the whole widget and not just the chip itself.

Re: Intel's New Chimera: Alder Lake

#223

Post by helldritch »

therealbilly wrote: post #205
helldritch wrote: post #153

Earlier quoted context omitted.

That's a fair point, although some people do constantly multitask. I have ADHD and I'm capable of doing work while focussing entirely on two tasks, often I'm looking at one screen where I'm writing code while reading an article on another screen. Sometimes I feel like "reality" is too slow and I've already figured out the code for the unit test (or whatever I'm working on) in my head and I'm impatiently waiting for m…

Do you take Vyvanse? That is what I take. It makes a world of difference!

I do! I was on 30mg for a week, then increased to 50, and I've been stable there ever since.

I was worried at the start I would end up on 70mg, but it just seemed to work from day one onwards.

Do you get the reduced appetite? I basically don't eat from 11am until 8pm most days, which has worked quite well for weight loss. I wasn't super heavy (18st, now 14.5st) but I had put on quite a lot during COVID.

Re: Intel's New Chimera: Alder Lake

#224

Post by admax88qqq »

delusional wrote: post #46
em500 wrote: post #37

Earlier quoted context omitted.

The top Alder Lake desktop CPU has 16-cores, 8P+8E, compared to 8P in the 11-th gen. The E cores get around half the performance of the P cores, so the 8P+8E is get roughly the performance of a hypothetical 12P+0E CPU. The very high core parts are reserved for Xeon (a 56 core Alder Lake Xeon has been leaked, but I think the P/E split is still unknown). What people need to realize is that a P cores takes around 4 time…

It's worth making it explicit that many home computing tasks are highly parrallelizable because the work is actually completely separate programs. If you watch a video while writing a document in word, that's trivially parrallelizable.

That's not highly parallelizable, that's only 2 task.

If those two tasks aren't themselves multithreaded (which they arn't if you're doing them in your browser) then you need at most 3 cores.

All the other background processes in your browser and OS are not using any significant CPU time, and can all comfortably share a fraction of a single core.

Re: Intel's New Chimera: Alder Lake

#225

Post by r00fus »

ggreer wrote: post #210
destroy-2A wrote: post #3

Earlier quoted context omitted.

I think the article is is saying it won’t lead to much of anything except headaches.

That's the impression I got as well. That made me discount Agner's arguments since they apply to Apple's M1, and the M1 is great in both raw performance and power efficiency.

Difference: Apple controls software + hardware and can this immediately utilize hardware efficiencies like a new Arch with a simultaneous release. Intel doesn’t control Windows.

Re: Intel's New Chimera: Alder Lake

#226

Post by Veliladon »

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 so they don't have to change the topology from the ring bus in the consumer parts while boosting the effective core count. Look at a 12900K block diagram. Four efficiency cores plus their combined L2 take up the same amount of die area as a P core. This means they don't have to deal with mesh interconnects or something like Infinity Fabric (which they already tried on Ivy Bridge-EP and were sorely dissatisfied with) and kick the can further down the road.

Re: Intel's New Chimera: Alder Lake

#227

Post by zaptrem »

pohl wrote: post #163
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…

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).

Re: Intel's New Chimera: Alder Lake

#228

Post by zaptrem »

fancyfredbot wrote: post #118

It's strange Agner seems so against this hybrid design despite the fact it's been proven to work so well for ARM. I'd agree this architecture is very difficult to optimize a single application for, but on the other hand he doesn't seem to consider whether it can lead to better performance and battery life in everyday use cases with mixed workloads using less than 100% of available performance.

He seems more annoyed about bad software thread management in Windows 11 (and none at all in Linux and MacOS) and that P & E cores have different instruction set support, which messes with apps.

Re: Intel's New Chimera: Alder Lake

#229

Post by zaptrem »

iforgotpassword wrote: post #19
esperent wrote: post #9

Earlier quoted context omitted.

Such a condescending comment. Why should this "idiot gamer", who might be a child, be expected to know about this stuff?

Yes, an attempt at sarcastically describing Intels train of thought was made. But really, why would a child change random bios settings anyway? You can easily render your system unbootable by changing random things there. Better make knifes illegal before an unsupervised toddler hurts themselves?

That's how they learn! I'm forever grateful for all the times I accidentally bricked my PC and had to work my way out of it.

Re: Intel's New Chimera: Alder Lake

#230

Post by paulmd »

ByteJockey wrote: post #144
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…

> they just don’t want to pay licensing fees to use them Can you blame browser makers for this? When was the last time you saw someone pay for a browser? Pre-2005 Opera?

Google makes enough money off Chrome and youtube they could afford to pay licensing fees so that end-users have a good experience. Software decoding vs hardware decoding is a massive difference in user experience.
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