[lttng-dev] LTTNG on Android ICS

[Ionut D.]

Great informations! I will post back the results.


On Fri, May 17, 2013 at 4:47 PM, Pierre-Luc St-Charles <
pierre-luc.st-charles at polymtl.ca> wrote:

> Alright, small update for all following a quick (non-mailing-list)
> exchange:
>
> We did successfully complete a kernel-tracing port of LTTng for Android
> (somewhat old news), but we are still working on bringing our patches back
> up to date with the current version of the different projects (soon-ish
> still applies here, we're talking days). So far, we dwelled a little bit in
> LTTng-UST, but haven't done much changes, so userspace tracing is still not
> functional. Device that ran kernel traces successfully so far were the
> Nexus S and the Nexus 7 (example Nexus S trace available here<https://drive.google.com/folderview?id=0B55Ba7lWTLh4U0hGeTQ4bmRYRjQ&usp=sharing>;
> still not perfect).
>
> Basically, we cross-compiled everything via the Android NDK (no Android
> makefiles involved here), and pushed all required bins to a device without
> having to flash it (unless the default kernel config didn't allow tracing
> -- then we'd have to flash). This approach is not compatible with the
> official Android build system (meaning we wouldn't be able to add it to
> Android like this), but we might eventually get working on the damned
> Android makefiles (they're extremely painful to write, especially since
> LTTng uses Autotools).
>
> The librairies required by LTTng that are not already included in a
> regular Android build (uuid/popt) can actually be found/compiled from the
> official repo, in its 'external' directory (see oprofile and e2fsprog --
> from memory). That might not be the easiest way to get them (full repo
> download is BIG), but compatibility is assured, and you can skip a full
> build by simply making those two individually for your device (if that's
> all you need).
>
> You'll also need your device to be rooted to use LTTng at all; then, most
> initializations are done via scripts (we'll also provide those with our
> patches). We still had some trouble automating everything via daemons, so
> we always ran the sessiond locally (with success).
>
> Major problems we encountered so far were missing posix functions, and
> sysv shared memory. Basically, Android relies on Bionic for its system
> calls and other low-level functions, and since Bionic is pretty
> 'lightweight', they trimmed most of the fat out for performance. We had to
> make some more-or-less sketchy replacements here and there, but everything
> seems to be working decently now.
>
> So, simple 'how do I put LTTng on Android' workflow would be this:
>
>   - Compile modules (using NDK) against device's kernel, making sure its
> config is appropriate, ship them over via ADB
>
>   - Compile required external libraries (using repo build system) for the
> device, ship them over via ADB
>
>   - Patch up LTTng-* (soon-ish! I could send you the outdated patches
> right now if you're interested though, they might be a month behind or so
> on the current trunks)
>
>   - Cross-compile LTTng-* for the device (using NDK), ship binaries over
> via ADB
>
> Then, on the device, start up the sessiond manually & start tracing.
>
>
> I think I went over everything, but if there's a part that's still cloudy,
> don't hesitate.
>
>
> -PL
>
>
> On May 17, 2013 1:32 AM, "Ionut D." <ionut5001 at gmail.com> wrote:
>
>> Hello all,
>>
>> Recently I started to integrate LTTNG in Android ICS by compiling each
>> package, each dependency, by using the Android build system. It is a lot of
>> work because I met different problems and to be sincere, I do not know if
>> at the end will work and I do not know how much I will need to modify the
>> sources in order to work.
>>
>> My questions are about this integration. I mention that I read a lot of
>> discussions about this on Internet, on this mailing list, but the things
>> are still not very clear for me.
>>
>> It is ok? what I am trying to do ? to integrate and build by using the
>> Android build system.
>> Could you give me some guidelines, indications about how I should
>> proceed, maybe a tutorial or maybe some android make files/patches that
>> would help me to see how the job must be done and if I am doing it right ?
>>
>> Until now I managed to build lttng-modules, liburcu, libuuid from
>> util-linux and configure lttng-ust by using the android toolchain for arm.
>> I got a lot of errors but until now I managed to configure/make these
>> packages.
>>
>> I mention that I am trying to build lttng 2.x on ICS 4.0.3.
>>
>> Would be great if you will give me a tutorial about how to do it.
>>
>> Ionut
>>
>> _______________________________________________
>> lttng-dev mailing list
>> lttng-dev at lists.lttng.org
>> http://lists.lttng.org/cgi-bin/mailman/listinfo/lttng-dev
>>
>>
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