yashsingh1/xdaforums huggingface dataset:
[Galaxy S 4 General] AndreiLux:
No confirmation. There's actually more evidence for it than against it, I don't see a reason why they would bother to have the drivers in the first place in the source code and ROM if it weren't possible unless there is some major ****up, I mean hell, there's a video of it running on a tablet. It just seems unfinished.
[Galaxy S 4 General] Halim2k:
Thanks,

Let's hope for the good then
[Galaxy S 4 General] DADER:
Andrei you seem having opposite writings in two threads ;in this thread you say octa has cluster migration, on the other thread of yours you say octa works by pairs atm. Now I am really confused because I am willing to get this phone but also i like perfected properties not wrapped up by rush ones, also in that thread you say its only because of IKS & in this one you say its because of hardware limitations!!

:-$

Can you clearify this foggy info. to me pls.

Spoiler content hidden.
[Galaxy S 4 General] vampyren:
I have the i9505 and its a beast plus the battery is damn amazing, cant do anything but recommend it. I also have 4G now so more reason for S600. Honestly the performance wise (CPU/GPU) these 2 are very close to each other and with 3 time more power than S3 it dont matter anyway, its like sitting in a Ferrari or Porsche both are great :D
[Galaxy S 4 General] vid200:
I agree, but kind of think future development will go in optimizing octa version so I got one for me and one for my wife. We will see how it goes.
[Galaxy S 4 General] Tears for Fears:
Exynos was never as developer-friendly as Snapdragon was, plus currently, 70% of all sold Galaxy S4s are the Snapdragon version, you can bet it'll have more developers. We have no guarantees that I9500 can get this fixed at all. Or even how well it can be optimized. Who knows, maybe all of the great developers will improve the I9505 so much that it could surpass the I9500?
[Galaxy S 4 General] vid200:
I do and don't agree. The 9500 is not finished yet, so Samsung will optimize it on its own at first. The way I see it. Second, the 9500 is a challenge for developers and all the testing and comparison so far has shown some advantages of octa core. There might be more development for 9505 but that doesn't mean anything quality wise. IMHO.
[Galaxy S 4 General] vampyren:
Exactly what i was thinking, most users have the S600 and by the time exynos version is in a good enough shape its time for N3 :)

Sure its a challenge to work with exynos but still its not a walk in a park with S600 since its a brand new chip so it will be enough excitement. Also seeing other brands like HTC One uses the same chip if i were a developer i would for sure go for S600 which is more widely spread.

I do like to see more of exynos but it just dont seem to be a mature product as snapdragon model, just my feeling and opinion. Also isnt CG already out for S600 ? give a hint on what directions devs are going ;)
[Galaxy S 4 General] harise100:
When I look into the development section Exynos is getting much more attention than the snapdragon!!??
[Galaxy S 4 General] demlasjr:
Naw, there are two section. Development and Original Development. In original most of them are from S600. The others from I9500 are most of them just data gathering from the firmware, but nothing done or fixed.
[Galaxy S 4 General] eric-filth:
Octa have Andreilux. :thumbup:

Dot.

Enviado do meu GT-I9300
[Galaxy S 4 General] Tears for Fears:
Samsung promised to optimize it but we know nothing of what it will do or if it will fix any issues at all. We can only guess wildly. The superior quantity means a higher possibility for quality development so quantity is crucially important.
[Galaxy S 4 General] vid200:
Also quantity means more BS so more work and time to find out best. The time will tell. But even if the optimization will take time up until note3 comes out, I am not scared since note is absolutely too big for me. I never had one and I think I never will even if it looks perfect. But it will come in few months so at least than our 9500 will have some movement.

Up until than my research points it is superior to 9505, but at the end, that is just MHO. Even 9505 is perfect, the difference I assume is very,very small.
[Galaxy S 4 General] Tears for Fears:
Don't be so sure, an old Snapdragon S2 phone got its performance improved about twice than out of the box. Of course, when numbers are such high, reaching double is significantly more difficult and perhaps not doable but I'm just saying that you shouldn't doubt Snapdragon's potential, especially when so many devices are running the 600. According to analysts, the sales of S4 may reach up to 100 millions, so if I9505 will keep its 70%, that's 70 millions against 30 millions, obviously.

We can only guess but I9505 has so many advantages over I9500 that I9500 is a dangerous choice, that is, if you want best of the best.

For those of you who want to be safe and have a *somewhat!* guaranteed bright future for your phone (even after two, three years), I suggest I9505, if you like living dangerously and like to gamble, I suggest I9500, because on its best scenario, it can be indeed quite superior to I9505 and even a lot of future flagships from competitors, but on its worst scenario, you can end up regretting with overheating problems, battery drain neural to I9505 and every other of the same generation, turn out inferior in performance and even incompatibility issues.

My personal thoughts.
[Galaxy S 4 General] demlasjr:
[MENTION=4591280]Tears for Fears[/MENTION] deserves a Nobel for his post
[Galaxy S 4 General] Entropy512:
That's because most of the AOSP-derivative kangers wait for CyanogenMod to do the initial bringup work, and that's been done outside of XDA. (Steve doesn't like XDA much for a variety of reasons, mostly due to kangers.) Even if he did publish work directly here, it would be in the T-Mo variant forum.

CyanogenMod is already in a nearly daily driver state on the T-Mobile and Canadian variants in a matter of days. No one has even started on the I9500 and so far I have yet to talk to someone who plans to do that and has the skills to succeed. I9505 also hasn't had work started, but I expect that as soon as a maintainer decides to go for it, it'll take about as long for them to bring it up as it took dvtonder to bring up the Canadian variant (which was a matter of hours).

I9505 also shares an SoC with many other devices, plus the Snapdragon 600 is an EXTREMELY close relative of the S4 Pro found in the Nexus 4, Find 5, and Xperia Z. Seriously, the APQ8064T/AB (I've seen it referenced with both T and AB suffixes) is almost identical to an APQ8064 except for the CPU cores themselves. Same GPU, same display subsystem, same wifi, same bluetooth - same EVERYTHING but the cores themselves.
[Galaxy S 4 General] Obagleyfreer:
Please excuse the "noobishness" here Entropy512 but does that mean as the i9505 shares the same SoC with so many other devices it would be easy for developers to port Roms from the HTC One or the Experia Z onto the i9505?
[Galaxy S 4 General] rakeshishere:
He meant AOSP based rom development would be easier.

You buy a I9505 and run CM you're just doing it wrong because GALAXY phones have plethora of features (useful, gimmicky, bloated etc) over AOSP based roms ;)

I wish gokhanmoral could give his insights on this Exynos issue on S4:)
[Galaxy S 4 General] shiann:
I think that may be the hardware limitation, the IP has been designed for cluster operation.

In ARM's web site. that describe below. (in hardware tab, www arm com/products/processors/technologies/biglittleprocessing.php)

"Both the Cortex-A15 and Cortex-A7 processors are available to partners now, and available in production separately with first big.LITTLE silicon now being demonstrated by lead licensees. The second big.LITTLE pairing is between the Cortex-A57 and the Cortex-A53 processors, successors to the Cortex-A15 and Cortex-A7 processors respectively."
[Galaxy S 4 General] Entropy512:
Cross-porting manufacturer firmwares is next to impossible.

However, for AOSP variants (CM and derivatives), it means that it is MUCH easier to bring up a new device.

See, for example, the Oppo Find 5. About a week of prep work (figuring out the CAF start point, chunking up kernel commits), a heavy weekend of bringup work, and CM was 90% complete in just a little over a week from when xplodwild, nebkat, and I got the devices in our hands. It is now more stable and functional than any of the Exynos4 devices we supported in only 3 weeks or so - and some of those Exynos4 devices we worked on for over a year. Pretty much only a few small camera tweaks and misc other polishing remain.

Also look at the T-Mo and Canadian S4s - Steve had the T-Mo version 80% working in just a day, and it's probably 95%+ complete now after just a week. Canadian S4 took only hours to bring CM to. I9505 should take any competent maintainer only hours when one steps up.
[Galaxy S 4 General] demlasjr:
Octa vs S600

http://m.gsmarena.com/samsung_galaxy_s4-review-914p6.php

They made a mistake. That GLbenchmark is the 2.5 Egypt, not 2.7
[Galaxy S 4 General] AndreiLux:
Well that's very non-representative. I'm getting a tad better numbers on all benchmarks; 3500 geekbench, 660ms sunspider, 28.5k quadrant. GLB seems to be the only ever reliable benchmark.
[Galaxy S 4 General] demlasjr:
Also S600 scores better than what they say there. No idea what kind of phone they have and how they made the tests, but even Antutu looks wrong for both of devices
[Galaxy S 4 General] fishcake13:
Correct me if im wrong but doesn't S2 run on Exynos chip... ?
[Galaxy S 4 General] noideaforusername:
He meant the Snapdragon S2 chip, not the Galaxy S2.
[Galaxy S 4 General] dkenz:
I read somewhere that only 4 cores are active at one time... little - big... Big goes into play when a demanding app is used. So 3 little and 1 big are running and whatnot.. Yet if this is the case i wanna know why the Octa core phone runs faster benchmarks than the quad core snapdragon. Quad core snapdragon is 1.9ghz all 4 cores... Any combination of the little-big cores would be slower what gives?
[Galaxy S 4 General] Steve_max:
First: according to AndreiLux, Samsung did something stupid with either the CPU driver or the CPU silicon itself, and the migration between big and little is made by block, not by core. So you either have four "little" A7 cores active, or you have four "big" A15 cores active. There is no way to get, say, 3 "big" and 1 "little" active at the same time. Read the topic...

Second... The A15 cores on the Exynos 5140 are faster than the Krait 300 cores on the Snapdragon 600. Just like an i7 at 3GHz will run every task much faster than a Pentium 4 at 3.6GHz (even if the task is single threaded), the Samsung cores are much faster than the Qualcomm cores. They also use more power, which is the reason why you have the slow, but efficient A7 cluster.

Third, remember that benchmarks stress different parts of a system. If you write a graphical benchmark that is tailored for the way the Adreno GPU works, it will give amazing results on the Adreno-equipped I9505 and bad results on the PowerVR I9500. Look at 3DMark for example, it gives high scores to every Snapdragon-based phone due to its Adreno chip, even higher scores than much faster GPUs from other manufacturers.
[Galaxy S 4 General] Entropy512:
No, there are three. There's an intermediary mode, which is where each core has a "sibling" in the other cluster. Tasks on a given core will migrate to a given "sibling" depending on load. e.g. one A15 active at full tilt, and three A7s at very low utilization as one example. (Whether to ramp up a single A7, or run across three of them at minimum speed, is always a difficult decision to make...)

The key is, each cluster is only capable of operating at a single frequency. So, for example, if you have one core fully loaded, but just need a "little extra" for a second thread:

In the current Exynos implementation, a second core gets lit up at maximum frequency. Traditionally, Samsung's multicore cpuidle support has been ****, so this usually means that the second core is at maximum voltage and never power-gates. In modern CPUs, static leakage current can be as much as, if not more than, dynamic power consumption.

In the case of Kraits such as the Snapdragon 600, every core is capable of operating at independent voltages and clocks. So in this situation, core 0 would be at full tilt, and core 1 would be at minimum voltage/frequency.

In the anticipated implementation for Exynos that we were all expecting, the second core would get lit up on the A7 cluster, and remain at a low clock for that cluster. e.g. a "ghetto" version of Qualcomm's asynchronous clocking. But we didn't even get "ghetto async".

The final implementation is where the four cores of each cluster are completely independent of the other, and can be "lit up" independently of each other. Don't expect this to come any time soon from the company that couldn't even properly implement cpufreq policy enforcement in the initial ICS release for the I9100.
[Galaxy S 4 General] luigi90210:
If you don't mind me asking, what would the purpose of having let's say 1 a15 core running while 3 a7 cores running?

The way I understand it is that the phone is either in a low performance state or high performance state, having those inbetween states wouldnt do anything because there isnt a state in which the phone will run in a medium performance state.

My closest analogy is having a compound turbo set up on a car(so 2 turbos 1 small and 1 large), the small turbo is used for low end power and when you hit a certain psi (let's say 12psi) it switches everything over to the bigger turbo because at that point the small turbo is being out flowed by the bigger one and leaving it enabled will just rob power from the big turbo.

I'm not trying to insight an argument here, just trying to learn(if that makes sense)
[Galaxy S 4 General] AndreiLux:
If the load exceeds the capacity of the A7 cores, there's no advantage.

However if a load can be accommodated by the little cores, you have a 3x power efficiency advantage for a given computation over the big cores. Currently given a high load thread which loads one or more cores for the CPU to switch to the big cluster, any other computations on the remaining CPUs get a power disadvantage.

I don't get your power state reference, the CPU has a ton of power states, each frequency is a power state and you have 17 of those, or 17 efficiency points. It also has three possible power states, so you have 51 possible power levels per CPU.
[Galaxy S 4 General] luigi90210:
ok let me rephrase it, there are not very many things the a7 processor(especially a quad core a7) cant handle so everything from 200-1200mhz would run with the a7 but lets say you start a processor intensive task(IE Gaming), wouldnt it be more logical for the a15 processor to just handle that?

i cant realistically see a situation where you would only need 1 a15 core and 3 a7 cores

i guess the real question i am asking is why would you want to set up something like that when it wouldnt be used as often(or it could glitch and start switching cores when it isnt needed killing more battery)?

again im not trying to start anything, just want to understand what the advantages would be and how often it would be used
[Galaxy S 4 General] trein91:
Not all apps have perfect multi core processing. There are heaps of apps that only run on one. Let's say 1 app requires one a15 core, surely you don't want all the other processes to switch to a15 cores as well. Idle mode on a7 will consume less than that on a15.

At least that's how I think it works out. Hopefully someone else clarifies if for you.
[Galaxy S 4 General] Entropy512:
Yup. Suppose you have a single highly intensive thread or process (this is common) - this will peg the first core at maximum speed (A15 at maximum clock).

While that is running, some lower-intensity background task wants to run. Let's say, for example, maybe an audio effects processing thread for a game. This second thread doesn't need nearly as much power as the main thread, so can fit on an A7 core, possibly even at a frequency below 1200 MHz. As a point of reference, I frequently see one core at 1.5 GHz and 2-3 cores at 384 MHz on Qualcomm APQ8064 devices.

With the current setup, this second thread will "light up" a second A15 core at maximum voltage/clock. I should look at the cpuidle driver, but if it's as crippled as Exynos4 was, this means that when the core is idle (which it will be a significant part of the time), the core will only be clock-gated but not power-gated. So it will consume MUCH more power than if it were on an A7 core for the same amount of work.

Optimal core configuration really depends on the voltage/frequency profile of the processor and on the thread configuration. For example, it may be better to have 3 a7 cores operating at 200 MHz rather than one at 600-800, depending on how much the voltage increases to hit 800.
[Galaxy S 4 General] obaid_rock:
ok so after reading 16 pages.. i still dont get it.. first thing.. will this be fixed? becauz ryt now the battery life is not as good as i was expecting.. while sleeping... it gets down by like 7-8 percent.. my S1 never did that! n it hardly goes a day with even normal usage.. n it gets hot for no obvious reasons.. i knw this all have been said b4.. but will this be fixed.. like in future update? are there any mods to fix it? btw i have i9500!
[Galaxy S 4 General] Nghtmare:
Yeah i was about to ask the same thing since i read it all and understand how it works and how it should work to improve battery life. Im still not clear though if this can be fixed by software, i mean i think it should since its the governor i think that tells the phone how the cores should (i can be wrong thought). But im also interested on knowing if it can or not be fixed, because me like all of you guys bought the i9500 for the processing power but mainly due to the battery improvements it was supposed to bring.
[Galaxy S 4 General] yahyoh:
actually nobody 100% sure if its hardware limitation or unfinished kernel :/

its not governor issue its something deeper in the kernel in cpuidle driver and big.LITTLE clusters and cores migration driver aka IKS :rolleyes:
[Galaxy S 4 General] Nghtmare:
I see what you mean, thanks for clearing that up for me. Well isnt still software related? Because the processor its still the same one, its just that the cores are not working in a hybrid type of way you can say, its either one or the other, but it should be software i want to believe (and i also hope so). But if someone that actually knows how this works can bring some light to the topic it would be really appretiated. By the way i believe if would solve the little overheating problem the phone has since all 4 A15s wouldnt be running together unless its needed.
[Galaxy S 4 General] yahyoh:
BTW even with cluster migration Octa has about the same battery with S600

I9500 VS I9505 battery test :good:

http://translate.google.com/transla...www.adslgate.com/dsl/showthread.php?t=1556211

Octa with core migration or MP should do slightly better ;)
[Galaxy S 4 General] Nghtmare:
It should do better in about every way, dont know how much but it should. Lets hope we can get this corrected.
[Galaxy S 4 General] Mithrandir007:
I think it should only do better when doing light tasks or when the device is idle.

Because in that test, they did an hour of gaming + other relatively intensive tasks which could have used the A15 CPU.

When the A15 CPU is running, the battery is most likely draining faster than the SD600 version.
[Galaxy S 4 General] Nghtmare:
Yeah youre right, on tasks where not all four A15 are requires it would be able to save battery.
[Galaxy S 4 General] AndreiLux:
They have core independent power collapse states. Previous architectures didn't have this because of hardware reasons, not software. You couldn't collapse a single core while keeping its coherency in the system. Tegras were in the same boat and also had these limitations while relying on hotplugging.
[Galaxy S 4 General] shadowcore:
So, I did not get a single thing out of this thread,

What is the problem here?

The 9500 not switching to the 4 shadow cores that are meant to save battery when on low use? If they dont work as intended than thats sad.

If they do, I dont get the fuss about this thread.
[Galaxy S 4 General] trein91:
Did you even read the thread at all? Fuark all you need to read is a few pages back.
[Galaxy S 4 General] noideaforusername:
No, the problem is there are only 2 options for the CPU (h/w or s/w restriction is unknown):

1. 4 A7 cores.

2. 4 A15 cores.

So you can't for example have 1 A15 and 3 A7 cores running at the same time. This is not very efficient since we almost never use all 4 A15 cores on heavy usage and even 1-2 can be enough.
[Galaxy S 4 General] shadowcore:
Ah, ok. I get it now. Thanks for clarifying.

Would not that depend on the app and how it utilizes quadcores or is it strictly load driven(Like how intensive an app is: 3D games with lots of objects)

From what I know, its a hardware limitation. If its a cluster, than it should be impossible to switch just one core from one cluster and 3 from another because how the architecture.

Reminds me of the tegra 3 or 4 companion core.
[Galaxy S 4 General] noideaforusername:
It is depends on the app but if the app need 1 A15, than all the 4 A15 need to work.

This is exactly what is unknown.

According to their presentations (they showed case of 1 A15 and 3 A7 working together) it should be s/w limitation that can be fixed later.
[Galaxy S 4 General] yahyoh:
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[Galaxy S 4 General] Bluey47:
Great discussion. Read the entire thread and makes sense to me.

Quick questions for you guys. Trying to decide on which S4 to get, care more about idle battery life than mod-ability.

1) If the i9500 never used the A15’s. Are the A7’s more efficient than the S600?

2) Is it possible to limit the i9500 to only the A7’s? Through clock speed limiting or something similar and then have a widget that can toggle the setting? (I am definitely an Android Root Noob)

3) Apart from everything running slower would there be any other side effects?

Regards,

Bluey47
[Galaxy S 4 General] demlasjr:
1) A7 are more efficient that S600's A9, off course.

2) It's possible to limit the A15 cores, off course, but there is no widget or app yet.

3) no side effects, but probably the phone will lag hard. Jelly Bean is not made for A7.
[Galaxy S 4 General] AndreiLux:
You can use any app to limit the CPU to the little cores via frequency. And it works very well, many people won't even notice the difference.
[Galaxy S 4 General] mw86:
This works interesting setting for example rom toolbox cpu control to screen off 1200mhz max and screen on 1600mhz max... Giving the A7's reign for screen off activities and full power available during more needed screen on activities. Personally more will be had from great developers like you Andrei pushing to improve the way these run via kernel.
[Galaxy S 4 General] yang.felix:
The CCI bus is key to support core migration or HMP. It's not necessary to cluster migration. Currently if you try to access any registers of the CCI bus, your system will hang. It's very possible the CCI bus isn't powered on and rightly clocked, if so the A15 cluster and A7 cluster doesn't connect to CCI bus, the question is if they don't connect to CCI, how they connect to DRAM controller and where is the CCI bus. From kernel source we know the CCI bus does exist.
[Galaxy S 4 General] <<CodeMaster>>:
That won't really have much impact for the average person.

What would you have running in the background, with the screen off, that would require the processing power of the A15 cores?

Generally with the screen off, the handset would be running on the A7's regardless.
[Galaxy S 4 General] mw86:
Gee why so critical? True not a big difference but just android process media could push it into A15 with ease and that can't be the only high load process that is common. Downloading and transfering files would stay cool with screen off. No there would not be a big difference but it would still save energy for those that use their phone plenty with screen off.