Alpha4 release status

Mon Jun 18 07:58:56 UTC 2012

So where are the bad news? :D sounds great! and sounds like alpha 4 
might come soon :)
enjoy QCS.

thanks a lot Marco

PS, let me know when you hear from kde.
ciao

On 06/17/2012 12:58 PM, BogDan Vatra wrote:
> Hello everyone,
>
> I have some good and bad news.
>
> I changed the atomics in order to make the safe, I chose the fifth
> approach and it seems they are just a little bit slower, because it
> has to do an extra function call. The good news are there is no ABI
> break, so I can still play my favorite GPLv3 Qt game which I bought it
> a few months ago :). No, I'm not crazy :)! I bought a GPLv3 game
> because I like it! It also helped me a lot to test alpha4 branch. The
> bad news is that the application start up is still slower comparing
> with alpha3, this is because I've done a little hack in android assets
> implementation to keep the compatibility with alpha3. But if the
> assets access will be updated to alpha4, the start up is almost the
> same. I'm not going to fix this problem now, because I don't have
> enough time, after alpha4 is out, we'll focus on performance and
> bugfixes only.
>
>
> Cheers,
> BogDan.
>
>
> 2012/6/15 Tyler Mandry<tmandry at gmail.com>:
>> I say try 5) and benchmark it.
>>
>> I understand that you're trying to keep backward compatibility, but for such
>> fundamental and important changes, IMO it is far better to break the ABI now
>> than to pay for it in the future. Besides, we are still in alpha, breaking
>> the ABI should be considered a regular occurrence ;)
>>
>>
>> On Sunday, June 10, 2012 12:15:12 PM UTC-7, BogDan wrote:
>>> Hi,
>>>
>>> Many thanks for kind words !
>>>
>>> Sadly, the magic happened :). The good news is that it was my fault,
>>> the bad news it that my worst nightmare happened ... :(
>>> After I write my first mail I begin to cherry-pick all my changes from
>>> alpha4 and put them on top of alpha3 branch, then I spot a patch which
>>> caught my attention, and I really hoped it's not the cause of this
>>> problem, but it was ...
>>> Some time ago somebody complained on this mailing list about the fact
>>> that he could not be able to compile necessitas anymore using ndk-r7,
>>> soon I discovered that the atomics functions where not exported
>>> anymore in ndk-r7, then my nightmare began, first I post the problem
>>> on android-ndk mailing list[1], then Google suggest me that I should
>>> switch to gcc's built in atomics which I did[2]. I knew that the gcc
>>> built in atomics are not the fastest in the world, but I never thought
>>> that they are that bad. Android atomics support on necessitas is a
>>> long story, which began more than a year ago, I'll try to make it
>>> shorter for you :)
>>> For the very first android atomics implementation, I used Qt's arm
>>> atomics, but I had to switch to gcc built-in atomics (yes, the second
>>> implementation was based on gcc atomics) because Qt's arm5 atomics
>>> where useless for Android, I'll try to explain why: The problem is
>>> that Qt's arm5 atomics are not SMP safe, so, is probable that your app
>>> will crash on a dual-core device. arm5 is very important because it is
>>> supported by all arm android devices, so it must be SMP safe. I
>>> address this problem last year at QCS[3], and somebody offer to help,
>>> but sadly nothing happened. So, I had to find a solution myself, GCC's
>>> implementation is using a sort of memory barrier (a mutext or
>>> something) to make it SMP safe, that why is so slow, then I discover
>>> that google is providing atomics in libc, which they should be SMP
>>> safe, so I switched to android atomics, then google change their mind
>>> and now they are dropping the support, so I had to switch back to gcc.
>>>
>>> To "fix" this problem I see the following "solutions":
>>> 1. Ignore Google warning and keep using android atomics.
>>> 2. Stay with gcc atomics, but is too slow.
>>> 3. Build Qt libs with fast atomics, but find a way to have safe
>>> atomics for arm5.
>>> 4. Build Qt libs with fast atomics, but use GCC atomics for apps.
>>> 5. Build Qt libs with fast atomics, but don't make qt atomics inline
>>> anymore, this way your apps will use what qt provides for that
>>> platform. They will be a little by slower but they should be safe.
>>> This is my favorite solution, but I afraid that it will break the ABI
>>> ...
>>>
>>> It is safe to build Qt libs with fast atomics for arm5 because arm5
>>> libs will be downloaded Ministro *only* on arm5 devices and AFAIK
>>> there is no SMP arm5 device. The problem is that your apps are not
>>> downloaded by Ministro :) and if they are built only using armv5 they
>>> will be loaded by a SMP device and they will have problems, so arm5
>>> atomics must be SMP safe.
>>>
>>> Anyway we have to address the problem once and for all !
>>>
>>> If any of you has any other Ideas please don't hesitate to share them with
>>> us.
>>> Also any comments/feedback will be very appreciated.
>>>
>>> Cheers,
>>> BogDan.
>>>
>>>
>>> [1]
>>> https://groups.google.com/group/android-ndk/browse_thread/thread/a792d8392b01f389/ecbad8bb4981ed8d
>>> [2]
>>> http://commits.kde.org/android-qt/aa14a65fd29f20adb7aa22b354c975d76266bed1
>>> [3] http://community.kde.org/Necessitas/Meetings/QtCS2011
>>>
>>>
>>> 2012/6/10 Bruno Zerbo<bruno.zerbo at gmail.com>:
>>>> Thanks BogDan for your work.
>>>> cheers,
>>>> Bruno
>>>>
>>>>
>>>> 2012/6/10 BogDan Vatra<taipanromania at gmail.com>
>>>>> Hello folks,
>>>>>
>>>>>   Unfortunately I have more bad news regarding alpha4 release, I
>>>>> manage to fix the OpenGL problem, but I discover another one. The
>>>>> startup of all applications has slowdown a lot (2-4 times), the
>>>>> problem is the difference between alpha3 and alpha4 is huge (1000+
>>>>> patches). Alpha3 is based on Qt 4.8.0-rc and alpha4 is based on Qt
>>>>> 4.8.2, to be sure the problem is not caused by me, I have to
>>>>> cherry-pick all my changes and put them on top of alpha3, them, if is
>>>>> not my fault the pain begins, I'll have to merge Qt 4.8.0, check, then
>>>>> Qt 4.8.1, then Qt 4.8.2. This is going to be a very slow and painful
>>>>> process which will take days (even weeks) so, I don't believe alpha4
>>>>> will be out before QCS, unless a miracle happens and I'll found the
>>>>> issue in the next days.
>>>>>
>>>>> Sorry for the bad news ...
>>>>>
>>>>> Cheers,
>>>>> BogDan.
>>>>>
>>>>>
>>>>> 2012/6/4 BogDan<taipanromania at gmail.com>:
>>>>>> This http://files.kde.org/necessitas/installer/MinistroActivity.apk
>>>>>> is
>>>>>> the link to Ministro.
>>>>>>
>>>>>> BogDan.
>>>>>>
>>>>>>
>>>>>> On Jun 4, 2:02 pm, BogDan Vatra<taipanroma... at gmail.com>  wrote:
>>>>>>> Hi everyone,
>>>>>>>
>>>>>>>   As you may know the alpha4 release is approaching, the plan is to
>>>>>>> have it ready before Qt Contributors Summit. It is almost completed,
>>>>>>> I
>>>>>>> need a few days to polish the style plugin and Minitro and another
>>>>>>> few
>>>>>>> to add support for context menus.
>>>>>>>
>>>>>>>    A few days ago I pushed to Minnistro's "unstable" repository the
>>>>>>> current alpha4 branch in order to check if the existing released
>>>>>>> apps
>>>>>>> are still working. Even we've made some heavy changes and even if I
>>>>>>> warn you that it may break the compatibility with older versions, I
>>>>>>> wanted alpha4 to be backward compatible with alpha3, it is also a
>>>>>>> test
>>>>>>> for Necessitas developers to see if we can keep our promise: to ship
>>>>>>> releases which are backward compatible!
>>>>>>>
>>>>>>> If you want to try it yourself please follow the next two steps:
>>>>>>>   - uninstall official Ministro and use this
>>>>>>> onehttp://files.kde.org/necessitas/MinistroActivity.apk.
>>>>>>>   - install and run Ministro configuration tool (from market) and
>>>>>>> choose unstable repository.
>>>>>>>
>>>>>>> Don't forget that Ministro is not stable and it may crash/hang, if
>>>>>>> you
>>>>>>> encounter any problems please reply on this thread.
>>>>>>>
>>>>>>> Shorty after the repository was ready, I tried a few apps from
>>>>>>> market
>>>>>>> and two major problems pop up:
>>>>>>> - The first problem was related to some missing symbols and was
>>>>>>> caused
>>>>>>> by compilation/linking flags.
>>>>>>> - The second one is related to OpenGL and it seems to be caused by
>>>>>>> the
>>>>>>> merge with Qt 4.8.2.
>>>>>>>
>>>>>>> 1. Missing symbols problem: Android comes with almost no support for
>>>>>>> C++, so to compile Qt we used (static) gnu-libstdc++.
>>>>>>> Then I discovered that this was a big mistake (for more information
>>>>>>> check Android NDK docs/CPLUSPLUS-SUPPORT.html "II.3. Static
>>>>>>> runtimes:"
>>>>>>> section).
>>>>>>> We can not use link libstdc++ statically if we are using more than
>>>>>>> one
>>>>>>> shared libraries in a project. To fix this problem I had two
>>>>>>> choices:
>>>>>>>   - to use the shared libstdc++ implementation and to change all the
>>>>>>> scripts in order to add it to ministro (1.2M).
>>>>>>>   - to "embed" the whole library into QtCore library (it adds and
>>>>>>> extra
>>>>>>> 600K) but this change requires no additional changes.
>>>>>>>
>>>>>>> I choose the second one [1],[2] because it was safe and easy and
>>>>>>> mostly because it didn't needed any other changes.
>>>>>>> If anybody has something against this change speak now or forever
>>>>>>> hold
>>>>>>> your peace !
>>>>>>>
>>>>>>> I'd like to add exceptions and RTTI by default, if the size and
>>>>>>> speed
>>>>>>> will not be affected.
>>>>>>>
>>>>>>> 2. OpenGL problem: After I merged alpha4 branch with upstream Qt
>>>>>>> 4.8.2, most of the OpenGL apps are not working anymore, I tried to
>>>>>>> fix
>>>>>>> it my self but I end up with a very ugly workarround. It seems that
>>>>>>>
>>>>>>>
>>>>>>> "boolQGLContext::areSharing(constQGLContext*context1,constQGLContext*contex
>>>>>>> t2)"
>>>>>>> always returns false. I tried to trace the problem but with no luck
>>>>>>> and I end up adding a super dirty workarround: on android,
>>>>>>> "QGLContext::areSharing", will always returns true. I really don't
>>>>>>> like it, so until we'll figure out what is wrong the release process
>>>>>>> will stop ...
>>>>>>>
>>>>>>> Any help will on this matter be very appreciated !
>>>>>>>
>>>>>>> I've spot another minor problem with old assets support it was
>>>>>>> caused
>>>>>>> by "QString QDeclarativeTypeLoader::absoluteFilePath(const QString
>>>>>>> &path)" I fixed it locally but I didn't had time to push the fix to
>>>>>>> Minsitro's repository yet.
>>>>>>> I'll keep you post with the progress and with any Ministro
>>>>>>> repository
>>>>>>> changes.
>>>>>>>
>>>>>>> Cheers,
>>>>>>> BogDan.
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>> [1]http://quickgit.kde.org/index.php?p=android-qt.git&a=commit&h=8c4c862...
>>>>>>>
>>>>>>>
>>>>>>> [2]http://quickgit.kde.org/index.php?p=android-qt.git&a=commit&h=abe85f4...
>>>>