The Mobile CPU Core-Count Debate: Analyzing The Real World
by Andrei Frumusanu on September 1, 2015 8:00 AM EST- Posted in
- Smartphones
- CPUs
- Mobile
- SoCs
S-Browser - AnandTech Frontpage
Again staying with the S-Browser, we check the behaviour of just pure web-page rendering. This time we load the AnandTech front-page without scrolling through the page. The page is slightly heavier as we have more graphical elements as opposed to text on the previous article page.
This time around, we a more even distribution of the load on the little cores. Again, most of the 4 CPU cores are active and have threads placed onto them, averaging about 2.5 fully loaded cores.
The frequency distribution is much more variable in this scenario, as the cluster makes wide usage of the frequency range available to itself. On the power state distribution chart we see that most CPUs are still able to enter their power-gating states, indicating that we're mostly handling very short bursty loads.
The biges cores seems much less loaded in this scenario, as most of the time except for a small peak we only have 1 large thread loading the cluster. Because of this, we expect the other cores to be shut down and if we look at the power state distribution we guessed correctly.
The total amount of threads on the system doesn't change much compared to the previous scenario: The S-Browser still manages to actively make good use of up to 4 cores with the occasional burst of up to 5 threads.
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TylerGrunter - Tuesday, September 1, 2015 - link
In fact you are in the right place to ask that question, as one of the profets os the mantra was Anand Lal Shimpi himself:http://www.anandtech.com/show/7335/the-iphone-5s-r...
Quoting from the article:
"two faster cores are still better for most uses than four cores running at lower frequencies"
You can read the rest if you are interested, but that´s how much of the mantra started.
retrospooty - Tuesday, September 1, 2015 - link
I wont hold that against Anand, he was lobbying toward a job at Apple ;)But seriously, it was 2 years ago. At that time ""two faster cores are still better for most uses than four cores running at lower frequencies" may well have been the case. Also, no matter how you slice it, an 8 core big.little is not a true 8 core CPU. It's really still 4 cores.
retrospooty - Tuesday, September 1, 2015 - link
/edit. I do remember alot of people crying "you dont need 8 cores" but again, that was people misunderstanding ARM's big.little architecture made worse by marketing calling it "8" cores" in the first place.TylerGrunter - Tuesday, September 1, 2015 - link
I agree with you, and he may not have been THAT wrong at the time. But with the current implementations of power gating and turbos most of what he said has been rendered false.AFAIK, big.LITTLE can be a true 8 core, it actually depends on the implementation.
lilmoe - Sunday, September 6, 2015 - link
"Also, no matter how you slice it, an 8 core big.little is not a true 8 core CPU. It's really still 4 cores."An 8 core big.LITTLE chip running in HMP mode (like the Exynos 5422 onward) is in fact a "true" 8 core chip in which all 8 cores can be running at the same time. You're thinking core migration and cluster migration setups in which only 4 cores (or a combination of 4) can be running at the simultaneously.
lilmoe - Sunday, September 6, 2015 - link
"can be running at the simultaneously."*corrected: can be running simultaneously.
osxandwindows - Friday, September 25, 2015 - link
If i run all 8 cores at the same time, wood it affect battery life?mkozakewich - Wednesday, September 2, 2015 - link
If the option is really four weak cores or two powerful cores, I think the two powerful ones would make a better system. If we could have two powerful cores AND four weak cores, that would be even better.So I think he was probably justified.
mkozakewich - Wednesday, September 2, 2015 - link
Just everyone who's easily influenced, really. I heard it from pretty much everyone. Someone I was talking to apparently "knew someone who designed a Galaxy phone." He claimed they wanted to design it with two cores, or something, but the marketers wanted eight.StormyParis - Tuesday, September 1, 2015 - link
Very interesting, thank you.