[HACK] (!update 04/26/2010) JIT enabled Dalvik VM on Android 1.6 (Dusted Donuts)
Update (fix for /cache/dalvik-cache 04-26-2010)
: Really only use this if your having issues using the symbolic link fixes posted by other members or are just out of free space on /cache. First the new issues people are experiencing is in cm-based-kernels from 4.2.15.x and not JIT enabled DalvikVM and people using danger/death spl will experience problems faster. Lack of space on /cache is a problem and will cause market downloads to fail as well as email attachments. The other problem is the kernel fails for various and unknown reasons to mount bind /cache/dalvik-cache to /data/dalvik-cache.
The other issue is the use to dalvik-cache clearing scripts and options in RA recovery, stop clearing your dalvik-cache
, the .dex files are created when missing and you do not get any benefits by doing so and cause more wearing leveling of NAND, plus the script in RA recovery doesn't appear to look at /cache/dalvik-cache for dex files. This little update script (when installed correctly).
Understand that /cache/dalvik-cache is a newer option as a means to free up space on /data is by using /cache/dalvik-cache as a first storage of dex files then using the standard /data/dalvik-cache for over flow of dex files and newer installed apps. Somewhere along the way something may throw this and you get douplicate dex files in both locations, one way to check is to boot into recovery and
and check dalvik-cache directories in both /cache and /data for douplicate dex files.
The script will fix these issues, or should at least:
Endless loop FCs on boot
broken /cache/dalvik-cache mount
no binded mount
missing user apps
missing system apps
failed market downloads
non-working symlink patches and installers (no need to run these, they will break this patch)
fixes duplicate dex files in both /cache/dalvik-cache and <target>/dalvik-cache (because it deletes /cache/dalvik-cache)
Will not Fix:
your unwillingness to read
your unwillingness to learn
your compulsive ROM flashing disorder
your compulsive dalvik-cache clearing syndrome
version 1.1.1(updated 4/27/2010 @ 10:10 PM) is current and was slapped together from Phonekenstein, it doesn't look for the existance of /cache/dalvik-cache it assumes it's there and deletes it wether it's a directory, a symlink or a file, re-creates a new empty /cache/dalvik-cache with Android default permissions and mount binds it to /data/dalvik-cache (be it a directory, a symlink or another binded mount) /cache/dalvik-cache will follow the target /data/dalvik-cache (no worries for apps2sd users or non-apps2sd users).
Script will turn on the blue LED when booting so you know it executed (if it annoys you then edit the script and make it pink)
Tested on Cyanogen MOD 18.104.22.168 and SuperD 1.10.3:
with and without apps2sd
with and without a /dev/block/mmcblk0p2 (apps2sd script nulled)
with and without a custom /dev/block/mmcblk0p4
with mount binded /ext/dalvik-cache (mmcblk0p4) to /data/dalvik-cache
with /data/dalvik-cache as a symbolic link to /ext/dalvik-cache (mmcblk0p4)
All scenarios experienced no failures as long as you set your permissions correctly on all targets and files and /cache/dalvik-cache followed and binded flawlessly.
install is simple and can be done through terminal:
1. download 86dalvik-cache-fix
<--Long press and chose "save link as" (also attached to this post)
2. open terminal and issue these commands:
NOTE: COMMANDS ARE CASE sensitive in LINUX and as such ANDROID!!!!!!
ALL OFF THESE COMMANDS ARE IN lower case. SO Turn off your Auto-Caps options in your keyboard options. These command assume you downloaded the script using your the web browser on your G1/Magic whatever phone and the file is located in /sdcard/download (the default location for web browser downloads).
mount -o rw,remount /system
cp /sdcard/download/86dalvik-cache-fix.txt /system/etc/init.d/86dalvik-cache-fix
chown 0:2000 /system/etc/init.d/86dalvik-cache-fix
chmod 755 /system/etc/init.d/86dalvik-cache-fix
Why 86dalvik-cache-fix? We want the script to execute after all scripts in /system/etc/init.d/ including /system/sd/userinit.sh (if you are using one) and before script 99. 86 because in 1987 everything got 86'd.
If you are having a problem getting the script to execute, copy it or merge it into /system/sd/userinit.sh (even if you aren't using a mmcblk0p2(ext partition)) it may make it work with FastTest builds, however the permissions on his builds appear to be root everything and I have problems getting the script to execute out of /system/etc/init.d even with root permissions.
Primer: Read this about Dalvik VM http://en.wikipedia.org/wiki/Dalvik_virtual_machine
Read this to: Google Groups post about JIT compiler for Dalvik VM from Android-Platform Link
From the post we see that this particular compiled library is ALPHA
, so results can vary, but from reading most posts in this thread the results are right near the talked about 3x faster code, stability is going to vary on what apps and or widgets are running. More Widgets = slower performance as these have processes that are eating cycles. When testing with Linpack wait for the advertisement to load first then tap the benchmark button and remove your finger from the touch screen. Background process such that interrupt or having auto-rotate enabled while testing is going to give you slower benchmarks.
In short your apps should load faster and run faster, particularly 3D games. The web browser is faster and you can actually scroll through pages even while graphics are still loading.
The reboot when enabling it is long even appearing to hang at the G1 Screen for 5 minutes or more but once it starts booting past this you will know that your ROM is compatible. The cause is that the dex files are being optimized, after about a third reboot, your ROM should feel pretty snappy and launching apps should be quicker as well as switching apps. The snappiness lasts as well and as some may have said that it's a placebo effect
are wrong. Bench mark readings prove it and more importantly a few ROM builders have included this in their 2.1 ROMs as experimental.
The libdvm.so that t3steve
cross compiled for the DROID at the time was for Android 2.0, the library works for with newer ROMs Android 1.6 that have some eclair pieces built into the kernel, CyanogenMOD has been using bits and pieces for a while now, if other ROM builders have been using his kernel and framework than a good chance it will work for your phone as well.
I have nothing to do with the compiling of this or the exact functions of enabling JIT except that I had a hunch that the combo might work and it did, so I'm sharing it.
If you aren't good at typing in commands, or don't know how to extract a zip file and understand that a sub folder may or may not exist where you have extracted said zip file to, well.... you may run into some issues, maybe a video tutorial for basic command line on youtube would be a good place to learn.
I wanted to make a very detailed post on www.andoidonroids.com
about how to mash the JIT enabled Dalvik VM library into Android 1.6 Donuts I'm calling the hack "Dusted Donuts" and take from the name for what you will. I have been using the JIT enabled Dalvik VM for about two weeks and i runs decent but not perfect. Anyhow a death in the family Sunday has kept me from making a decent post and haven't had the time to get to the website and post and cross post and give credit where due.
No doubt that aaraya1516
broke the news on http://forum.xda-developers.com/show...&postcount=193
as he was first to break the hack on FastTest, not taking anything away from him on that.
My testing goes back two weeks or more even during the 580mhz & 780mhz hack, I was waiting for someone to compile a boot.img with some 2.x stuff and sure enough the carlospants boot.img from ctso
worked with enabling JIT for Dalvik VM, but as we know now the overclocking doesn't work at the moment.
of which may not know that this was entirely possible. Cyanogen mixed in enough Eclair into his Donuts (he's like Willy Wonka) that makes it possible to use the cross compiled JIT enabled Dalvik VM library from 2.1 for the Motorola DROID 2.0.1 libdvm.so that t3hSteve of www.alldroid.com
compiled for the custom roms on Droid.
Using other methods supplied from other forum members that include replacing the build.prop may cause problems
, using the build.prop from the original VMLIBS.ZIP (which is here for reference and original source for libdvm.so) is definitely going to cause ROM and application problems. Hello....use your head here... the VMLIBS.ZIP is for Motorola DROIDS, why would you put the build.prop file for a DROID on your G1 and expect your apps or ROM to work afterwards?
It's so simple, you need 1 file, it's called libdvm.so
it goes in /system/lib a file by the same name already exists there
and it's in your best interest to at least back it up before overwriting it and gives you the ability in the event that your system doesn't boot up you can restore it through recovery console and get your phone to boot past the G1 screen.
Some ROMs have the option dalvik.vm.execution-mode=int:fast in the /system/build.prop
file, this would need to be changed to dalvik.vm.execution-mode=int:jit
or commented out or deleted. If you want to play with advanced options create /data/local.prop and fiddle in there with options available from typing dalvikvm -h
in your console or terminal app.
1. Android 1.6 ROMS with a bit Eclair stuff in the Kernel and framework such as Cyanogen ROM 4.2.x, Super D 1.8 - 1.92, WG Y2.6, FastTest, KingKlick Eclair and more.. This libdvm.so works on Android 2.1 as well as it seems it should.. 1 st bootup is slow and I recommend you let it sit even when desktops are up for a couple of minutes and then reboot it, 2nd and 3rd bootups are faster and smoother response overall even for long durations, days.
FIX YOUR FILE SYSTEM FIRST
!!!!!! Got to do it from Recovery Console, It's partly the cause of poorly running ROMS and takes seriously longer to type the command than to fix your unknowingly faulty file system. EXT2 is the worst offender and the built in function to repair falls short, even more so when checking EXT4.
#e2fsck -fcpDC0 /dev/block/mmcblk0p2
For the lazy fingers
#e2fsck -fcpDC0 /*/*/*0p2
1. Download www.androidonroids.com/dusted-donuts
(File has 3 scripts backup, install, restore, 2 folders, 1 libdvm.so)
2. Extract zip to root of /sdcard or where ever you like (the zip has a folder containing the files named dusted-donuts)
3. Open Terminal or go to Recovery Console
FYI when running the install through Terminal your system may freeze or reboot and if it does I highly recommend that you prepare to enter Recovery Mode and check your file system. EXT2 corrupts quickly choosing this for apps2sd to use is not the best option especially if you are using custom ROMs that may lockup or reboot, basically that's a crash.
#mount -o rw,remount auto /sdcard
Check the Dalvik VM execution mode. look at the bottom line with_jit means the it is installed , and look at all of those options that can be jammed into your build.prop and local.prop files
Phone won't boot past G1 screen? Go to recovery console and restore libdvm.so (give it at least 5 minutes first before giving up)
#mount -o rw,remount auto /sdcard
prefer to use VMLIBS.ZIP from t3hSteve? This is how you can install using that.
1. Android 1.6 ROMS with a bit Eclair stuff in the Kernel and framework such as Cyanogen ROM 4.2.x, Super D 1.8 - 19.2, WG Y2.6, FastTest, KingKlick Eclair and more.. This libdvm.so works on Android 2.1 as well as it seems it should..
How to install: (easier to go in recovery mode but can be done through terminal)
1. Download the VMLIBS.ZIP from t3hSteve of allroid.com http://alldroid.org/download/file.php?id=1374
2. You only need the libdvm.so file of which appears to be JIT enabled by default.
3. Backup the original libdvm.so #cp /system/lib/libdvm.so /sdcard/libdvm.so
4. Copy the JIT enabled libdvm.so #cp -f /sdcard/vmlibs/libdvm.so /system/lib/libdvm.so
5. Set permissions on the file #chmod 644 /system/lib/libdvm.so
Optional for disabling: (easier to do vi through recovery console, since the back key escapes out of terminal)
To disable JIT MODE but want to keep the libdvm.so create a local.prop in /data and add dalvik.vm.execution-mode=int:fast
press the i key to enter vi interactive mode
press back key to exit vi interactive mode
to write the file out and quit vi type :wq
restore your backed libdvm.so file from the sdcard.
Enjoi! the dusted donuts,
-Licknuts (me? I'm like Varuca Salt, I want another pony)
Vendor G1 roms around 1.2 Mflops, Custom G1 roms are around 2.4 MFlops/s and with JIT compiled Dalvik VM 3.6 MFlops/s. At most you will see 3.5 MFlops/s fairly consistently with a minimal load on your system and highs at 3.7 Mflops/s. Test before and after using Linpack from the Market, it's free.
The 13.236 Mflops/s is not normal and you will probably not see with your testing, I have seen 5.x & 7.x but these are far and few between and this took a while with tweaked configurations/settings with a persistent app to kill processes, it is attainable and I hope a ROM developer finds the sweet spot to exploit.