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
Camera Video Recording
Video recording absolutely makes use of all little cores at once. As we see in the power state distribution chart all cores are predominantly in their active clocked states doing some work. The scheduler run-queue depth also points out that this is a case of at least 4 larger threads that reside on the small cluster.
During the actual video recording the big cluster runs at only 800MHz. Nevertheless, it still sees some activity as 3 cores have some small threads placed on them.
All in all it looks like video recording is about a large number of small threads. There are two spikes in the total run-queue depth that were predominantly caused by the little CPU cluster which pushed the total rq-depth up to 8 in for short moments. I'm not sure what caused the spikes as I remained relatively still during the recording and did no special activity to warrant such behaviour.
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nightbringer57 - Tuesday, September 1, 2015 - link
Very interesting article, much more favourable to multi-core designs than I would have thought.Each article page must have cost an insane amount of time. However, I still feel like some more information could have been useful. This article is geared towards real-world use cases, but I think it would be interesting to repeat this analysis on a few commonly-used benchmarking apps. I feel like this would be interesting to compare them to real-world uses and may help understanding the results.
ingwe - Tuesday, September 1, 2015 - link
Yes that would be very interesting. I am always curious about how synthetics actually compare to more real world applications.Azethoth - Thursday, September 3, 2015 - link
Every single synthetic I have ever seen vastly exaggerates the benefit. I would be interested in an actual real world use case that actually matches a synthetic. It would blow my mind if there are any.Andrei Frumusanu - Tuesday, September 1, 2015 - link
I'll do a follow-up pipeline on this if the interest is high enough.bug77 - Tuesday, September 1, 2015 - link
High enough +1.Please do the follow-up.
tipoo - Tuesday, September 1, 2015 - link
I'd definitely be interested.Drumsticks - Tuesday, September 1, 2015 - link
Yes! This would be neat. Also, great article!ThisIsChrisKim - Tuesday, September 1, 2015 - link
Yes, Would love a follow-up.HanakoIkezawa - Tuesday, September 1, 2015 - link
I'm not sure of the practicality, but I would love to see a follow-up with Denver k1 and the A8X to see how lower core count out of order and in order SoCs are handled.This seriously was a fantastic article Andrei!
kspirit - Tuesday, September 1, 2015 - link
Yes please! +1