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[DEV] HTC One X firmware | Partitions Info | [20.04.2012]

OP mike1986.

18th March 2012, 01:00 PM   |  #21  
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Quote:

NVIDIA’s Project Kal-El processor implements a novel new Variable Symmetric Multiprocessing(vSMP)technology.Not previously disclosed publicly, vSMP includes a fifth CPU core (the “Companion” core) built using a special low power silicon process that executes tasks at low frequency for active standby mode, music playback, and even video playback. The four main “quad” cores are built in a standard silicon process to reach higher frequencies, while consuming lower power than dual core solutions for many tasks. Allfive CPU cores are identical ARM Cortex A9 CPUs, and are individually enabled and disabled (via aggressive power gating) based on the work load.

I think that it's pretty clear that there really is 5 cores

Source : http://www.nvidia.fr/content/PDF/teg...aper-0911a.pdf
18th March 2012, 01:06 PM   |  #22  
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I think it's more possible that this 5th core is responsible for events that non of those 4 cores are suppose to take care off. I think it's taking care of low level processes, leaving pure OS to be taken care off by 4 main cores.

That will also explain why cpu0 is online all the time as well.

Screen OFF:
Companion core taking care of low level processes
cpu0 taking care of Android processes while system is in deep sleep state

Screen ON:
Companion core is still taking care of low level processes
cpu0 and cpu1 are online all the time taking care off Android OS
cpu2 and cpu3 are online ad-hoc on heavy load.
18th March 2012, 01:17 PM   |  #23  
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Quote:

The Battery Savercore is used primarily when the mobile device is in active standby and performing background tasks such as Emailsyncs, Twitter updates, Facebook updates etc. It is also usedfor applications that do not require significant CPU processing power,such as streaming audio, offline audio,and both online or offline video playback. Note that both audio and video playback, in addition tovideo encoding,are largely processed by hardware-basedencoders and decoders.
Unlike the Battery Savercore, the main CPU cores need to operate at very high frequencies to deliver high performance.Therefore they are built on a fast process technologywhich allows them to scale up to very high operating frequenciesat lower operating voltage ranges. Thus the main cores are able to deliver high performance without significant increases in dynamic power consumption.

From what I understand there, the core we call cpu0 does not really need to always be on. And that would be weird because how would tegra 3 save energy this way...
There must be something we are missing.

Source : http://www.nvidia.fr/content/PDF/teg...erformance.pdf
18th March 2012, 01:26 PM   |  #24  
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About lp2 state:

init.endeavoru.common.rc
Code:
write /sys/module/cpuidle/parameters/lp2_in_idle 1
Also something funny

Code:
# Increase read ahead size of mmc block devices from default(128) to 1MB
# Reduces power comsuption during video playback from sdcards
write /sys/block/mmcblk0/queue/read_ahead_kb 2048
write /sys/block/mmcblk1/queue/read_ahead_kb 2048
Last edited by mike1986.; 18th March 2012 at 01:35 PM.
18th March 2012, 01:46 PM   |  #25  
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it seems that the sasme core pipe is hidden in lg optimus 4x hd as well, since the only four active cores displayed in the debug app is 4 rather than 5, and hence the fifth although active appears to be dormant.
18th March 2012, 07:40 PM   |  #26  
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i think ill lock my decision for the One X purchase now, simply because im so interested in the Tegra3 concept

seriously out of the box approach, you have to at least give Nvidia that, this will lead to many interesting development scenarios

most reviewers and users of transformer prime confirmed better than expected battery time

its very hard to imagine they went through the trouble of producing a fifth core as well as the yields difficulties for such design, without a good reason, hek they patented the damn thing

we will see

speaking of nvidia....their Kepler GPU is craaaaaaaaaaaazy 1536 unified cuda cores, it makes me cry this will do magic for Mental Ray RT
Last edited by hamdir; 18th March 2012 at 07:52 PM.
19th March 2012, 01:32 AM   |  #27  
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Isn't this simply an implementation of the big.LITTLE processing concept ARM have been talking about for a while.

A high performance core, even in idle, will draw more power than an energy optimised low performance chip.

The 5th core is almost a sacrificial unit. It is there so you can receive calls, texts, emails and play music at a very low power drain.

When you do anything more taxing it is disconnected and the main CPU cluster takes over.

From memory the main CPU cluster is an A15 and the low power unit an A7.

No matter how much you poke around you won't see both units together as its delt with within the CPU.


EDIT: After posting I find the Arm article, DUH. --> http://www.arm.com/products/processo...processing.php
Last edited by jagaroth; 19th March 2012 at 01:33 AM. Reason: Added link
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19th March 2012, 09:09 AM   |  #28  
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great info. glad to see another tegra3 device out now. tegra3 works great on prime. that 5th. companion core barely sips battery juice on standby and low level processes.

to the one person who asked if all 5 cores can be online at once, the answer is no. Nvidia made it this way. they have a patent pending technology on the way it switches cores. low level processes and deep sleep handled by companion core. as soon as a task/app/process demands more power, it instantly switches on the higher powered core or cores.

I have the updated whitepapers on tegra3 and another whitepaper on benefits of multicore mobile CPU. Ill attach them to this post. they are in a zip file since the PDF file size exceeds what xda will let you upload.

hopefully with more developer eyes on tegra3, everyone can benefit. Prime is a great device and I'm sure this HTC phone with tegra3 will be blazing fast. we already hitting 1.7Ghz overclock on prime now. I think someone working on 1.8Ghz. would love to see this reach 2Ghz n be stable and not a major hit on battery(lol).

edit: OP, do you have a transformer prime also? PRIME REVOLUTION ROM
Last edited by demandarin; 19th March 2012 at 09:22 AM.
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19th March 2012, 03:08 PM   |  #29  
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wikipedia describes it pretty well:

http://en.wikipedia.org/wiki/Tegra

Quote:

Tegra 3 (Kal-El) series

The Tegra 3 is functionally a SoC with a quad-core CPU, but includes a fifth "companion" core. While all cores are Cortex-A9s, the companion core is manufactured with a special low power silicon process that uses less power at low clock rate but does not scale well to high clock rates; hence it is limited to 500 MHz. There is also special logic to allow running state to be quickly and transparently transferred between the companion core and one of the normal cores. The goal is for a mobile phone or tablet to be able to power down all the normal cores and run on only the companion core, using comparatively little power, during standby mode or when otherwise underutilizing the CPU. According to Nvidia, this includes playing music or even video content.[19] Compared to Tegra 2, the ARM Cortex-A9s in Tegra 3 now supports ARMs SIMD extension, marketed as NEON. It can also output video up to 2560×1600 resolution and supports 1080p MPEG-4 AVC/h.264 40 Mbps High-Profile, VC1-AP, and DivX 5/6 video decode.[20]

i guess the companion core does the SMP scheduling and presents the other cores virtually to the OS, and there is no need for the OS to know about the companion core
20th March 2012, 02:31 AM   |  #30  
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Interesting to see NVidias take on low power. Different from Qualcomms but along the same lines as the ARM road map.

With Qualcomms dual core chip in the Sensation in low activity mode the second core is like a USB memory stick, when its not needed it is completely removed from the system.

NVidia are closer to ARM in having a low power core for menial tasks the is switched out when demand rises.

Not sure how they can keep a patent on this with ARM implementing it on future processors unless it is limited to A9 and ARM are opening up A15 -> A7.

Regardless I want one to play with.

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android revolution hd, htc one x, htc sense 4.0, ice cream sandwich, mike1986
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