[ANNOUNCE] CSSU-thumb thread - stable Thumb2 on N900
 

WHAT IS THIS?

Cortex-A8 SoC we have in our devices supports several ISAs (Instruction Set Architecture):

- ARM
- Thumb
- Thumb2
- ThumbEE
- ...

Stock Fremantle, all CSSU flavors and all of the software in repos (excluding some like FB sharing plugin compiled by mistake with Thumb2 ISA) come with binaries (i.e. executable files, libraries) compiled using ARM instruction set, which is the most powerful and fastest. Every ARM instruction uses exactly 4 bytes of memory.

Thumb2 is another instruction set, which have most of the power and speed of ARM ISA, but its instructions could be 2 bytes in length instead of 4 bytes. According to some researches that can be found on internet, using Thumb2 ISA leads to reduction of code size in 30-40% without sacrificing much of the performance (some 2-5% performance decrease). Will explain how that benefits us later.

The logical question:

Why then Nokia didn't compile Fremantle using Thumb2 ISA?

The answer - the SoC revision inside n900 has silicon erratas (i.e. bugs in the hardware) which render Thumb2 compiled binaries unstable if no countermeasures are taken. A system without fixes for the erratas crashes randomly, not only in Thumb2 compiled executables/libraries, but in ordinary ARM ones too.

The countermeasures:

There are two erratas that must be workaroundеd on n900 in order Thumb2 compiled binaries to not lead to system instability: ARM errata 430973 and ARM errata 657417

The first errata(430973) is workaroundеd in kernel, CSSU-thumb repo contains a special kernel (kernel-cssu) based on top of kernel-power 51r1 which workarounds the issue. While workaround for errata 430973 is upstreamed, it does not work on n900 being the High Secure device. A special call to Secure Monitor( that is a piece of ROM in our SoC programed by Texas Instruments during chip manufacture) is needed to properly enable the workaround, and that is handled in kernel-cssu.

The second errata (657417) is workarounded in linker, all binaries in CSSU-thumb repo are compiled using Linaro gcc 4.7.2 and binutils 2.22.

What is the benefit?

Well, we all know that the major performance bottleneck on n900 is the amount (or better said the lack) of RAM. Constantly swapping pages in and out of memory leads to stutter, lag, etc..., you know ;) . A part of that RAM is used to hold the executable code, so the smaller the code is, the larger part of the RAM will be free to be used for data. While it is a simplified explanation, you should be able to get the general idea. In addition - smaller code means better code cache usage, less reading from the storage (faster application start times), etc.

With packages that are so far in CSSU-thumb repo, the code size is reduced with approximately 35MiB, more RAM and storage space will be regained in the future when more packages will be included

The catch:

errata 430973 is workarounded by clearing a special type of cache (Branch Target Buffer) inside the chip on every context switch made by the CPU. In theory that slows down the system. I didn't make any benchmarks, but from my "ordinary user" POV, there is no visible performance loss.

How to install it?

Make sure Nokia and Extras catalogs are enabled in application manager.

Using microb on your n900 click here and follow the instructions on http://wiki.maemo.org/Community_SSU, section Installation, from step 5 on (Hildon Application Manager (HAM) will launch...). cssu-thumb is based on cssu-testing flavor.

If you have kernel-power v51r1 or above, no custom kernel will be installed, as needed errata workaround is included in kernel-power v51r1 (and above)

Uninstallation:

There is no way to uninstall, i.e. the same rules apply as for the other CSSU flavors. The only way to rollback without messing with apt-get is to reflash. Or you can downgrade all of the packages manually using apt-get.

Setup a development environment

http://wiki.maemo.org/CSSU-thumb_too....7.2-linaro%29

USUAL WARNINGS:

This is still in highly experimental stage and while so far there are no known issues, I will take no responsibility for any damage and/or data loss caused by using CSSU-thumb repo. It is highly unlikely to happen, but be prepared to reflash if something goes south. Make a full backup of your data/settings/whatever before installing stuff from CSSU-thumb repo

You've been warned :P

Changelog:

15.06.2012 - 21.2011.38-1Tmaemo4-thumb7
- Qt libraries moved back to /opt
- added new packages: qt-mobility, clutter, libhildonfm, osso-gnome-vfs2

16.06.2012 - 21.2011.38-1Tmaemo4-thumb9
- added new packages: libalarm2, alarmd, libxml2

20.06.2012 - 21.2011.38-1Tmaemo4-thumb10
- added new packages: xserver-xomap, xserver-xorg-core
- fixed a bug in the kernel : Clear the IT state when invoking a Thumb-2 signal handler http://git.et.redhat.com/?p=kernel-k...62e8de4406ac7e

19.07.2012 - 21.2011.38-1Tmaemo4-thumb11
- added new packages: microb-engine

27.07.2012 - 21.2011.38-1Tmaemo4-thumb12

- toolchain upgrade to gcc 4.7.2
- microb-engine - fixed HTTPS TLS error
- Qt libraries rebuild with the new toolchain

29.07.2012 - 21.2011.38-1Tmaemo4-thumb13

- kernel upgraded

01.08.2012 - 21.2011.38-1Tmaemo4-thumb14

- fixed a bug in tinymail

04.09.2012 - 21.2011.38-1Tmaemo4-thumb16

- microb-engine source code was missing some stuff from maemo.org, rebased.
- add libcurl3 (7.26.0-1maemo1+0cssu1-thumb1) - fix for Facebook widget, photo uploader and MfE IPv6 problems

15.09.2012 - 21.2011.38-1Tmaemo5.1+thumb0

- rebased on top of 21.2011.38-1Tmaemo5.1 CSSU-testing
- changed versioning scheme
- added thumb-compiled camera-ui, alarmd, hildon-application-manager, apt, modest

Because of the versioning scheme change you should follow the instructions here if upgrading from 21.2011.38-1Tmaemo4-thumb16 or older version.

23.09.2012 - 21.2011.38-1Tmaemo5.1+thumb1

- added missing dependency (system-services (>= 0.3.8-68+0cssu0))
- Thumb2 compiled dosfstools and openssl

25.09.2012 - 21.2011.38-1Tmaemo5.1+thumb2

- Thumb2 compiled gdigicam and gst-plugins-bad

03.10.2012 - 21.2011.38-1Tmaemo5.1+thumb3

- Thumb2 compiled sqlite3, gstreamer, gst-plugins-base, gst-plugins-good

03.11.2012 - 21.2011.38-1Tmaemo5.1+thumb4

- Thumb2 compiled db4.2, pulseaudio, calendar-backend, evolution-data-server

26.12.2012 - 21.2011.38-1Tmaemo7.1+thumb0

- packages updated to latest CSSU-testing(21.2011.38-1Tmaemo7.1)
- Thumb2 compiled obexd, gnome-vfs-filechooser-backend, ke-recv, libmatchbox2, rtcom-eventlogger-async

06.01.2013 - 21.2011.38-1Tmaemo7.1+thumb1

- Thumb2 compiled pango, freetype, libpng, zlib, libxml2
- NEON-optimized upstream versions of libpng (~30% faster) and zlib (~8% faster decompression, ~18% faster compression)
- libxml2 recompiled against latest zlib

07.01.2013 - 21.2011.38-1Tmaemo7.2+thumb0

- packages updated to latest CSSU-testing(21.2011.38-1Tmaemo7.2) - blacklist fraudulent TURKTRUST intermediate certificates

07.04.2013 - 21.2011.38-1Tmaemo7.2+thumb1

* pixman upgraded to upstream version 0.29
* build microb against system libpng and zlib
* pulseaudio, qt and hildon-desktop upgraded to latest CSSU versions on gitorious

15.07.2013 - 21.2011.38-1Tmaemo8.2+thumb1

* packages updated to latest CSSU-testing(21.2011.38-1Tmaemo8.2)
* thumb-compile tracker, hildon, hildon-thumbnailer

3.11.2013 - 21.2011.38-1Tmaemo8.3+thumb1

* osso-systemui-alarm: Fix nsv_sv_play_event call
* maemo-security-certman: Change VeriSign certificate order, fixes supl.nokia.com not working

12.11.2013 - 21.2011.38-1Tmaemo8.3+thumb2

* upgrade glib to 2.24.1
* upgrade pulseaudio to 0.9.15-1maemo44+0m5+0cssu5
* Thumb2 compile alsa-lib, glib, pulseaudio, telepathy-glib, telepathy-gabble and osso-pdf-viewer

24.11.2013 - 21.2011.38-1Tmaemo8.3+thumb3

* upgrade hildon-desktop to 1:2.2.153-2+thumb0
* Thumb2 compile cairo, libx11, libxfont

30.12.2013 - 21.2011.38-1Tmaemo9+thumb1

* clock-ui: Open source rewrite of the nokia clock-ui, thanks to Adekker (ade)
* camera-ui: Added Fallback to DCIM if NOKIA_CAMERA_DIR or NOKIA_MMC_CAMERA_DIR environment variable is not defined
Removed some GLIB Warning messages when changing profile
* dosfstools: Fixed install paths, data will be installed to /usr/share instead of /share
* e2fsprogs: Updated to upstream 1.42.5, fixes fsck for ext* filesystems
* glibc: Enabled kernel implementations of epoll, ppoll and pselect
* fmtx-middleware: Fm TX now keeps running when headphones/usb is plugged in
* gtkfilesystemmemory: Moved development files to osso-memory-backend-dev, frees rootfs space
* hildon-welcome: Fixed not running when /proc/bootreason is missing (ie. an upstream kernel is used)
* initrd-progs: Open source replacement with new feature -G which prints block data to stdout
* ke-recv-extra: Fixed 100% Cpu use on 3.x kernels
* libcpaboutcssu: dpkg-query instead of shell hack, added luf
* maemo-tvout-control: Moved maemo-applet-tvout back into libs section, fixes control panel entry missing
* modest: Moved recursive imap operations into glib main loop, fixes 100% Cpu / freeze on imap sync
* modest-l10n: Added english string for mcen_fi_advsetup_update_all_folders
* osso-af-utils: Replaced call to getbootstate with read of /var/lib/dsme/saved_state,
fixed boot when /proc/bootreason is missing
* osso-calculator: Added support for top_application dbus call
* osso-systemui-tklock: Fixed bug #12701: Ball is moving when touching anywhere along the bar-slide
* profiled: Open source replacement version from Nokia (harmattan/nemo)
* qt4-x11-maemo: Added MeeGo libs, change compiler flags
* status-area-applet-battery: Open source replacement which works with BME hal, bq27200 hal, rx51-battery hal
* upstart: Enabled auto fsck on boot, added support for swap_opts in /etc/default/mount-opts
* Thumb2 compile clock-ui, e2fsprogs, gtkfilesystemmemory, ke-recv-extra, osso-af-utils, profiled

12.01.2014 - 21.2011.38-1Tmaemo9.1+thumb0

* fmtx-middleware: revert to 0.62, fixes US model issues

05.05.2014 - 21.2011.38-1Tmaemo9.1+thumb1

* hildon-application-manager: apt-worker performance improvements
* hildon-desktop: Fixed: BMO #12722: hildon-desktop crashes on malformed transitions.ini.
hd_render_manager_set_state clean up.
Many portrait related changes. Fixes BMO #12720: Incorrect lockscreen background.
Fixed: BMO #12725: Screenshot saving path is hardcoded
Fixed: Sometimes thumbnails are wrongly clipped.
tasknav: fix thumbnails clip and rotation while in transition
* glibc: Timezone information as of 2013(thanks to ade). Thumb2 compiled.

29.12.2014 - 21.2011.38-1Tmaemo10+thumb0

* apt: Avoid sending useless auth data via http and https
* camera-ui: Fixed HD codecs bitrate calculation and useage of unreffed
object
* clock-ui: Fixed alarmlist order, snooze and recurrent alarms
* dosfstools: check / clear dirty bit
* hildon-application-manager: Performance fixes, removed another PC Suite
error, red Pill option available
* ke-recv: Fixed support for upstream client, new options in
/etc/default/mount-opts, new gconf key /system/osso/mmc-preferred-volume
* microb-engine: For reading device name use file /proc/cpuinfo instead
/proc/component_version
* modest: Forward ported fixes for #11993, a crash in HTLM -> text
conversion and a few G_CRITICALS in account creation
* nokiamaps-navigation-provider: FOSS release
* osso-systemui-powerkeymenu: Add power_key_mode and power_key_menu_response
to powerkeymenu-dbus-names.h
* pulseaudio: Enabled ipv6 support, disabled useless logs
* status-area-applet-battery: Nokia BME reporting incorrect last_full property, so do not use it
* tinymail: allow TLS to alternative ports
* upstart: Use data=writeback for all ext3 and ext4 partitions (not only root)

29.12.2014 - 21.2011.38-1Tmaemo10+thumb1

* fix hildon-desktop version dependency

10.10.2015 - 21.2011.38-1Tmaemo11+thumb0

* calendar-backend: Fixed #12682 invalid iCal export
* cityinfo: Open source replacement, fixes world database
* glibc: Fix for CVE 2015-0235 (GHOST)
* ke-recv: Fixed mount script for fat parittions
* mce: Open source replacement, fixes for upstream kernel
* upstart: Fixed /etc/default/mount-opts conffile issues
* openssl: Upgrade to upstream 0.9.8zf + maemo patches
* osso-product-info: Open source replacement, fixes for upstream kernel
* pulseaudio-policy-enforcement: disable useless logs
* telepathy-gabble: Google talk fixes, do not ignore muc messages

Re: [ANNOUNCE] CSSU-thumb thread - stable Thumb2 on N900
 

Looks very promising. Good work.
Uninstalling can be done just trough HAM again and deleting the repo?

Re: [ANNOUNCE] CSSU-thumb thread - stable Thumb2 on N900
 

The same rules apply as for CSSU in general - no uninstallation, only a reflash. Will update the OP accordingly, thanks

Re: [ANNOUNCE] CSSU-thumb thread - stable Thumb2 on N900
 

Nice and clean im gonna do it now and test it many thanks :)

Re: [ANNOUNCE] CSSU-thumb thread - stable Thumb2 on N900
 

Just instaled, as I switched to Samsung Solid B2710 ;) I can test and flash the N900 ans often as requested. My system wasn't clean and I had a few problems.When launching the CSSU about and trying to scroll the setings closed automatically also when trying to search the HAM for conky the phone got stuck and I had to reboot. I will try to flash the phone clean and report then.

Re: [ANNOUNCE] CSSU-thumb thread - stable Thumb2 on N900
 

i need to reflash the phone soon anyway, and i'll test it later after it works with kp-settings.

Re: [ANNOUNCE] CSSU-thumb thread - stable Thumb2 on N900
 

Thanks for this new update. :)

I installed it just now for testing. I am constantly getting rebooted as soon as it gets to the desktop. Do you have any suggestions? :(

Re: [ANNOUNCE] CSSU-thumb thread - stable Thumb2 on N900
 

Which kernel does it boot?

Re: [ANNOUNCE] CSSU-thumb thread - stable Thumb2 on N900
 

I had the stock kernel with CSSU Testing. Did not have KP.

Re: [ANNOUNCE] CSSU-thumb thread - stable Thumb2 on N900
 

Guys, hold on for a while, for some reason the needed kernel is not flashed, gimme some time to check what's wrong, will make a new post when the problem is solved

Re: [ANNOUNCE] CSSU-thumb thread - stable Thumb2 on N900
 

Thank you.
I have a question: I had to remove CSSU because i needed the stock camera. The camera-ui2 has given me a little bit of trouble so installing stock camera itself remove the CSSU. As CSSU is needed for this, is it possible to keep the stock camera app along with CSSU.
Much thanks.

Re: [ANNOUNCE] CSSU-thumb thread - stable Thumb2 on N900
 

im now restoring my backup because CSSU kernel not booting and i dont want the stock one :o thanks for the update much appreciated hope there will be a fix :)

./sifo

Re: [ANNOUNCE] CSSU-thumb thread - stable Thumb2 on N900
 

Hey Sifo,
How can you restore from backup, when you are not able to boot? Even I dont want to reflash. Is there any way to restore, without having to reflash via flasher?

Re: [ANNOUNCE] CSSU-thumb thread - stable Thumb2 on N900
 

@ramesh.kumar

backupmenu

Re: [ANNOUNCE] CSSU-thumb thread - stable Thumb2 on N900
 

You just installed a whole load of thumb2 binaries with a non-thumb2 compatible kernel. You can either:

1. Attempt to reflash nokia kernel (highly unlikely to work).
2. Wait for the fixed kernel and attempt to manually flash it (if it is even possible).
3. Full reflash of your device.

Re: [ANNOUNCE] CSSU-thumb thread - stable Thumb2 on N900
 

Or, if you're handy with repositories and have a Linux system handy, just extract the proper kernel from the package in the new repo and flash it directly. Should work, in theory.

Also, if you used backupmenu, since the kernel didn't change, you could in fact just do a restore. The one thing backupmenu doesn't do is backup/restore the kernel used by the system as part of the backup. But if that hasn't changed, you should be golden in just doing a restore from the image made before you tried the install. (You did do a backup right before that, didn't you? ;) )

Re: [ANNOUNCE] CSSU-thumb thread - stable Thumb2 on N900
 

Wow, how I wish :(. I did take a backup, but unfortunately, I dont have backupmenu installed. I am on Mac. I think, I should be able to flash it from there. Can you point me to the repo location?

Re: [ANNOUNCE] CSSU-thumb thread - stable Thumb2 on N900
 

Sorry, but if you can't figure out the repo location from the installer link in the first post, odds are you don't know how to find, download, extract, and hand-flash said kernel, and I don't have the time right now to make a 20 step how-to guide.

This is one of those learning moments. Either learn how to do this (Google is your friend), or learn that you shouldn't be using highly experimental software on your device.

Re: [ANNOUNCE] CSSU-thumb thread - stable Thumb2 on N900
 

Dependencies problem fixed, installation should be ok now. Sorry for the troubles :o

EDIT: after installation is complete you may want to do apt-get remove kernel-cssu-bootimg, for some reason it is pulled by HAM as a dependency while not really needed.

Re: [ANNOUNCE] CSSU-thumb thread - stable Thumb2 on N900
 

Greets, thank You for this one. Would really like to try it out.
I have a question: As I understand, all the applications we have are compiled using ARM. Does that mean they wont work with this update?

TIA

Re: [ANNOUNCE] CSSU-thumb thread - stable Thumb2 on N900
 

They will continue to work.

Re: [ANNOUNCE] CSSU-thumb thread - stable Thumb2 on N900
 

Hello. I have a dependency problem with "Maemo Kernel power config for multiboot". If i uninstall it, will i be able to install it again to use nitdroid?

Re: [ANNOUNCE] CSSU-thumb thread - stable Thumb2 on N900
 

when i click on the update on HAM it says i need pc suite to update it. how to solve that?

Re: [ANNOUNCE] CSSU-thumb thread - stable Thumb2 on N900
 

Since I m not afraid of having to flash, I just ran root and then apt-get update and apt-get upgrade and lived happily ever after.

However, the literal cause of the problem is you don't have enough memory to update. You could minimize the number of programs you hane installed and remove installed repositories and do other tricks to increase rootfs memory.

Or you could actually install pc suite.

Re: [ANNOUNCE] CSSU-thumb thread - stable Thumb2 on N900
 

Go to see the details and you will see what's the problem. You will need to unistall something, in my case it is "Maemo Kernel power config for multiboot". But i won't do it because i don't want to lose nitdroid.

Re: [ANNOUNCE] CSSU-thumb thread - stable Thumb2 on N900
 

sorry for the off topic

Brian_7 you will lose your N900 with multiboot and nitdroid :p

Re: [ANNOUNCE] CSSU-thumb thread - stable Thumb2 on N900
 

I was worried that this would conflict somehow with MaeMeeMo, but I haven't had problems. My N900 seems faster than ever -- feels like it's gaining on my N9!

Re: [ANNOUNCE] CSSU-thumb thread - stable Thumb2 on N900
 

Now it works ;)
After the update with thumb system after restart uses about 90mb instead of 106 without it. I hope that this project will move on as the benefits are clear!!!

Thank you for your hard work freemangordon (and merlin1991 for hosting it ;) )

Re: [ANNOUNCE] CSSU-thumb thread - stable Thumb2 on N900
 

A good test of Thumb2 power might be using a rebuilt version of Firefox, as it's the most memory offender application for the N900.

Re: [ANNOUNCE] CSSU-thumb thread - stable Thumb2 on N900
 

with this i suppose the performance lost by using thumb2 is less noticable in low memory situations due to the gain made reducing i/o to swap. great achievement getting this far but as it is my only device i'll hold off for now until its had a little broader testing.

i noticed you stated it reduced memory footprint by about 30mb. it would be interesting if someone could put together a comparison of memory usage for some common apps compiled with and without thumb support to illustrate the difference.

all we need now is a way to avoid swap fragmentation, maybe a different allocation startergy @ kernel level. ereswap solves it in userland for now but, no direspect intended, i don't feel it is the best solution.

Re: [ANNOUNCE] CSSU-thumb thread - stable Thumb2 on N900
 

ivgavez: like your idea. would be better maybe to rework microb if we have the full source yet. that way more people would be able to compare to something the have used. any improvements could then be rolled into cssu or extras.

Re: [ANNOUNCE] CSSU-thumb thread - stable Thumb2 on N900
 

Gecko is a dog, true, but most of its footprint is data so the ISA won't make much difference.

I suspect any significant performance improvements will only materialise after at least the most commonly used libraries and the X11 stack have been rebuilt. Until then most processes are going to be switching between ISAs all the time (and dropping the BT caches to boot).

Cf http://syslog.movial.fi/archives/46-...ot-to-VFP.html (currently down, archive copy here).

Re: [ANNOUNCE] CSSU-thumb thread - stable Thumb2 on N900
 

i would definitely add a warning that one needs at least ... free space on rootfs. /cleaning up right now

Re: [ANNOUNCE] CSSU-thumb thread - stable Thumb2 on N900
 

Well, I don't think the comparison with n800 is fair, what we have here is not thumb, but thumb2. Which is a totally different beast. There is no performance hit because of ISA switching, as there is no ISA switching :p. BTW I thumb2 compiled microb, and the difference in code size is about 7-8 MiB, which is a HUGE difference, having in mind browserd is always running. Unfortunately I was unable to run that binary and didn't have time to check why it aborts. microb will be my next favourite for thumb2 compilation once what is done so far is proved to not bring problems

@don_falcone: yeah, will add such a warning once I am back home, the reason is that Qt libs (being much smaller) are moved to rootfs from /opt. Theory says we sholud have an additional performance gain for Qt applications if libs are on faster NAND (NOR or whatever :) )

Re: [ANNOUNCE] CSSU-thumb thread - stable Thumb2 on N900
 

i have 65mb free on rootfs. cant install it. is it risky to install??

Re: [ANNOUNCE] CSSU-thumb thread - stable Thumb2 on N900
 

...hey man, my rootfs space is more tight than a ...! ;) Can i remove kernel-power afterwards? Especially the modules?

Re: [ANNOUNCE] CSSU-thumb thread - stable Thumb2 on N900
 

An analogy, not a direct comparison :-) A lot of the same underlying issues apply, ie you won't see much of the potential performance improvement until you have converted most of the software stack.

Well, if you have a thumb2 binary issuing calls to the standard (non-thumb) libc etc, there's going to be switching. Or am I missing something?

Indeed, that does sound significant :-)

Re: [ANNOUNCE] CSSU-thumb thread - stable Thumb2 on N900
 

hehe. Maybe you should work harder on that ... rootfs :p

Deffinitely. You can remove all of the kernel-power stuff and dpkg --force-all install KPS .deb

@Mohammed Muid: yes, what we're discussing with don_falcone is something in the range 10-15 MiB

Re: [ANNOUNCE] CSSU-thumb thread - stable Thumb2 on N900
 

...too little, give some slack and say 25Mb at least. I had 4MB free and was forced to temporarily move out 'beta' theme, locale-archive, dsp libs, nokia-maps, poker-th, and so on & on. Afterwards the upgrade i had 152kB left :eek:

Re: [ANNOUNCE] CSSU-thumb thread - stable Thumb2 on N900
 

OK, going to update the first post