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 Launching
I wanted also to have a closer look at CPU behaviour while using the phone's camera. First off, we start off by analyzing what happens when we launch the camera application.
Nothing much to report on the little cores, we only see some minor load on a couple of threads while the camera is running.
Most of the work when launching the camera was done by the big cluster. Here we see all 4 cores jumping into action. It's interesting to see that at these smaller time-scales we can observe how the CPU frequency lags behind the actual load on the cluster, as the frequency governor maintains a higher frequency for some time before falling back to the idle 800MHz.
Samsung seems to be able to parallelize well the camera application as this is again a sensible scenario that makes good usage of the 4.4 big.LITTLE topology of the SoC.
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modulusshift - Tuesday, September 1, 2015 - link
Heck yes. And of course I'm interested if anything like this is even remotely possible for Apple hardware, though likely it would require jailbreaks, at least.Andrei Frumusanu - Tuesday, September 1, 2015 - link
Unfortunately basically none of the metrics measured here would be possible to extract from an iOS device.TylerGrunter - Tuesday, September 1, 2015 - link
Add one more vote for the follow up with synthetics.I would also want to see how the multitasking compares with the Snapdragons as they use the different frequency and voltage planes per core instead of the big.LITTLE.
But I guess that would be better to see with the SD 820, as the 810 uses big.LITTLE. Consider it a request for when it comes!
tuxRoller - Wednesday, September 2, 2015 - link
Big.little can use multiple planes for either cluster. The issue is purely implementation, tmk.TylerGrunter - Wednesday, September 2, 2015 - link
big.LITTLE can be use different planes for each cluster but same for all cores in each cluster, Qualcomm SoCs can use different planes for each core, that's the difference and it's a big one.https://www.qualcomm.com/news/onq/2013/10/25/power...
I'm not sure that can be done in big.LITTLE.
tuxRoller - Friday, September 4, 2015 - link
I remember that but that doesn't say that big.LITTLE can't keep each core on its own power plane just that the implementations haven't.soccerballtux - Tuesday, September 1, 2015 - link
to balance everything out-- meh, that doesn't interest me. most of the time I'm concerned with battery life and every-day performance. Android isn't a huge gaming device so absolute performance doesn't interest me.porphyr - Tuesday, September 1, 2015 - link
Please do!ppi - Tuesday, September 1, 2015 - link
Go ahead. This is one of the most interesting performance digging on this site since the random-write speeds on SSDs.jospoortvliet - Friday, September 4, 2015 - link
Yes, this was an awesome and interesting read.