Gentoo for Amlogic S9xx (TV box S905\S905X\S912)

fosco · n00b Joined: 06 Jan 2017 Posts: 3

Hi all!
Just wondering...
what do you figure would happen adopting

erm67 · l33t Joined: 01 Nov 2005 Posts: 653 Location: EU

I think I will settle for much simpler version of package.accept_keywords:

NeddySeagoon · Posted: Sun Jan 08, 2017 7:48 pm Post subject:

fosco,

Welcome to Gentoo.

You are correct.

The ACCEPT_KEYWORDS setting only affects the 'visibility' of packages considered by portage for use in dependency calculations.
In your example, all the stable packages on amd64 would be considered. That does not mean they would build or work if they did build.
You just would not know that they were not tested.

You could also (try to) emerge packages that are known to not work. This is especially true of binary packages.
nvida-drivers, icedtea-bin, firefox-bin, libreoffice-bin, virtualbox ... You would get amd64 code.
We might well hear the crash when you try to run that :)

icedtea, firefox and libreoffice all build and work on arm64. It the case of firefox, the version you get with ACCEPT_KEYWORDS=amd64 will build but not run.

I would suggest that the short term gains are outweighed by the more subtle issues you are going to have.
It will also cause confusion when you get asked to post your

mDup · Apprentice Joined: 14 Apr 2006 Posts: 212

mDup · Apprentice Joined: 14 Apr 2006 Posts: 212

mDup · Apprentice Joined: 14 Apr 2006 Posts: 212

By the way:

It seems even with -j3 make flag (I have 4 cores and want to keep one available), some gentoo builds keep 6 cores going, and, no need to tell: temp rising ...

OK say, upto around 60 degC, perhaps OK since another box lives on 80 degC.

But eventually box may give up and crash on high temp.

Ideally I guess I should buy a switch and a 7 or 15 or 31 boxes farm to compile distcc and cc-cached together
:mrgreen:

erm67 · l33t Joined: 01 Nov 2005 Posts: 653 Location: EU

erm67 · l33t Joined: 01 Nov 2005 Posts: 653 Location: EU

mDup · Apprentice Joined: 14 Apr 2006 Posts: 212

erm67 · l33t Joined: 01 Nov 2005 Posts: 653 Location: EU

I also have a beelink but the mini-mxII, the only hw component non working in linux is the temp sensor :-)

so I have no idea about the temperature but even after heavy emerge the case is only lukewarm at touch ...
I bought an S905 because I had read some complaints about S905X not being stable with linux.

I was using this flags CFLAGS="-O2 -pipe -march=armv8-a+crc+fp+simd -mabi=lp64 -mcpu=cortex-a53+crc+fp+simd" (only crc is required since fp and simd are on by default) cat /proc/cpuinfo will tell you the extensions supported by the cpu, autodetection was broken on gcc <6 and extensions not automatically enabled.
GCC6 supports the native target and I use this now:
CFLAGS="-O2 -pipe -march=native -mabi=lp64 -mcpu=native" I tested several binaries and the two strings produce the same binaries on my arch.

LibreElec uses -ftree-vectorize for kodi and ffmpeg that should produce very fast code using the asimd extension, considering that I used a lot libreelec without problems I guess that tree-vectorize should be ok at least for some apps. tree-vectorize system-wide is usually not a great idea. graphite is masked on gentoo arm64 (probably the voices again since I read android uses it) it should give a bit more performance together with -flto and use ld.gold as a linker. Consider that some ebuild will strip out cflags 'for your safety'.

The next hurdle for me is to get java, which is again masked despite working perfectly in all other aarch64 distro.
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mDup · Apprentice Joined: 14 Apr 2006 Posts: 212

Hu · Administrator Joined: 06 Mar 2007 Posts: 22705

Portage will (usually) pass your preferred --jobs=N line to the underlying build system. Whether that build system respects it is an open question. I recall seeing one build system mentioned recently (ninja, I think) that ignored the user's choice and spawned however many jobs it thought the system ought to be able to handle. Personally, I would file a bug on packages that blow past user job settings like that.

On the other hand, I think that you ought to improve the cooling to the point that the box is stable with all cores spinning at 100%. For current personal sized systems (i.e. with cores <= 16), this should be an achievable goal.

You could also try using kernel settings to prohibit Portage jobs from using the system at full capacity, such as by restricting it to run the jobs only on a subset of available CPUs. This would reduce heat usage and work in the presence of ill-behaved build systems.

erm67 · l33t Joined: 01 Nov 2005 Posts: 653 Location: EU

His CPU is a Cortex-A57 it is a BIG/little architecture that has 4 fast power hungry core and 4 slower energy efficient cores, it uses heterogeneous SMP, in theory the slower cores are started first and when they reach 80% the faster cores are started by the scheduler. I am not sure that the 8 cores are really used all at the same time at the physical level even if it appears so, since according to the benchmarks it is not twice as fast as a 4 cores.
_________________
Ok boomer
True ignorance is not the absence of knowledge, but the refusal to acquire it.
Ab esse ad posse valet, a posse ad esse non valet consequentia

My fediverse account: @erm67@erm67.dynu.net

erm67 · l33t Joined: 01 Nov 2005 Posts: 653 Location: EU

NeddySeagoon · Posted: Tue Jan 10, 2017 10:42 am Post subject:

mDup,

mDup · Apprentice Joined: 14 Apr 2006 Posts: 212

mDup · Apprentice Joined: 14 Apr 2006 Posts: 212

NeddySeagoon · Posted: Tue Jan 10, 2017 2:45 pm Post subject:

mDup,

Its all native builds on Raspberry Pi 3 in 64 bit mode. I have found distcc to be more bother than its worth. Fixing that is on my todo list though.
The Pi 3 has 1G RAM and a 4G swap. Swap was 2G and I didn't have any build failures for running out of swap but I did see it go down to 10 Mb free, which is too close.
SD card write performance is really poor, so I build on a USB HDD.

erm67 · l33t Joined: 01 Nov 2005 Posts: 653 Location: EU

mDup · Apprentice Joined: 14 Apr 2006 Posts: 212

mDup · Apprentice Joined: 14 Apr 2006 Posts: 212

NeddySeagoon · Posted: Tue Jan 10, 2017 4:24 pm Post subject:

mDup,

Its a 'rotating rust' USB HDD. On the Pi I get 30Mb/sec.

The PI microSD is only 25MB/sec read.
Write speeds vary wildly from card to card, as low as < 2Mb/sec for sustained writes on an XC-I card.
They start out well then drop off.
_________________
Regards,

NeddySeagoon

Computer users fall into two groups:-
those that do backups
those that have never had a hard drive fail.

erm67 · l33t Joined: 01 Nov 2005 Posts: 653 Location: EU

The internal eMMC of the box (with TRIM support, so speed wont drop with time) is small (16GB) but not bad:

mDup · Apprentice Joined: 14 Apr 2006 Posts: 212

erm67 · l33t Joined: 01 Nov 2005 Posts: 653 Location: EU

/dev/mmcblk0p2 s probably your sd card, it doesn't support TRIM and the write speed will very soon drop to ~0 ......

There are varius ways to use the internal memory, the less risky way that also preserves your android environment is to boot balbes (or kszaq) kernel from sd and use /dev/data as root partition you can use another android partition (like /dev/cache or /dev/system) for swap but don't forget to go to android recovery and format cache&user data&system again before using android.
The root device is probably set in your uboot environment, altering uboot variables probably involves a very slight risk of bricking, it is safer do it on a serial console; a quick and dirty way is decompress the init image, extract it and modify the init bash script to boot from the /dev/data partition, recreate and compress the init image put it on the sd card and boot. Move the gentoo system to /dev/data first, that should be easy for you. This way you'll be using the sd only for booting.
The extreme solution is convert the binary dtb to dts (decompile), edit it to create the partitions you want, and recompile it.

What sounds less complicated and risky to you?

There is another way of course boot from the sd and than switch root to /dev/data, it is good to prepare the gentoo system.
_________________
Ok boomer
True ignorance is not the absence of knowledge, but the refusal to acquire it.
Ab esse ad posse valet, a posse ad esse non valet consequentia

My fediverse account: @erm67@erm67.dynu.net