[Interest] Interest Digest Wiki instructions for PI cross compile do not work for PostgreSQL support

Vlad Stelmahovsky vladstelmahovsky at gmail.com
Fri Oct 20 09:14:09 CEST 2017


I've created much more complex apps using QtQuick 1 on HW much weaker than
RPi2 (Symbian phones) w/o such laggin as in this simple calc example.
Obviously, there something wrong with code and/or system setup

On Fri, Oct 20, 2017 at 7:49 AM, Filip Piechocki <fpiechocki at gmail.com>
wrote:

>
>
> On Oct 20, 2017 00:11, "Roland Hughes" <roland at logikalsolutions.com>
> wrote:
>
> It's not misleading when it is a hog fattened way past market.
>
> 90% of the embedded systems I encounter have no GPU so the driver issue is
> irrelevant. You get rid of all needless things to improve battery life.
> Claiming an i.MX6 which most certainly must need grid power or batteries
> the size of a house is the "normal" embedded processor for medical devices
> or industrial control is simply ludicrous.
>
> And how much of embedded market are devices you are talking about? 5%? 1%?
> 0.1%?
>
> 90% of embedded devices I encounter DO have GPU and these are TVs, set top
> boxes, phones, public transport systems and even fridge. Oh, and using HW
> parts that are specifically designed for some things (like GPUs are for
> graphics) often gives much higher performance/(power draw). Of course it
> depends how much you will use it.
>
> I was using a Pi-II not a 1. The Pi-II has waaaaaaaaaaaaaaaaaaaay more
> horsepower than the vast majority of embedded systems I'm talking about.
>
> But it is still very weak CPU (I don't know the details but llvmpipe
> driver might be limited by single core performance so not much difference
> between RPi 1 and 2) and you are forcing it to draw OpenGL which this CPU
> would like to not handle at all as it is not designed for this. Already
> shown example of Qt Cinematic Experience which is much more
> sofisticated/fancy than your example app and can run on decent frame rates
> on RPi 1. Like said earlier - do this in widgets or whatever you like
> technology and compare development time (so EFL is out...) and performance
> (so HTML5 is out...).
> Oh, and you are wrong already in a second sentence of your blog post as
> one can think that there is no difference between HTML/JS app and QtQuick
> app. There is. I've run Servo browser engine benchmark limited to 60 items
> on i.MX6 in chromium and got 8fps. Then redo this in QtQuick and got stable
> 60fps. That's 7.5x better. But this discussion makes me think that I need
> to do this in widgets too. Any suggestions how?
>
> Please do not mislead people. QML is a horrible wretched thing which
> should never have seen the light of day.
>
> If there is no need for it in your specific market - it is ok. In one of a
> companies I worked we had huuuge desktop application done in Qt and I will
> never suggest doing it in QtQuick as widgets are perfect choice for it. But
> there are many solutions where there is need for technology like
> QML/QtQuick, even if it is not perfect (and it is not).
>
> Ok, so maybe you are not misleading people with your blog post - you're
> just showing them that application that is not supposed to be done with
> QtQuick which requires decent HW accelerated OpenGL since December 2012
> (ok, it has changed recently but still hw accelerated graphics is what you
> want) when done in QtQuick and ran on weak CPU and no HW OpenGL then
> performs poorly. Wow. Thanks Captain Obvious! You could have asked me and I
> will tell you the result without doing anything. But guess what - it has
> nothing to do with JS engine in this particular example, so your statements
> are wrong.
>
> Offering up "The Microsoft Solution" of "throw hardware and grid power at
> it" is simply no solution for the vast majority of embedded systems
> especially in the medical field.
>
> On 10/19/2017 02:04 PM, Filip Piechocki wrote:
>
> On Thu, Oct 19, 2017 at 2:43 PM, Roland Hughes <
> roland at logikalsolutions.com> wrote:
>
>> Scroll down and watch the video. QML is an 800 lb gorilla trying to ride
>> in a 2 cylinder car.
>>
>> http://www.logikalsolutions.com/wordpress/information-techno
>> logy/raspberry-qt-part-12-qml-blows-big-stinky-chunks/
>>
>
> Application used here is of course the best candidate for widgets
> implementation as it does not use QtQuick advantages.
>
> Do this:
> https://www.youtube.com/watch?v=wulbR2R1GpM
> in Qt Widgets and share your results.
>
> But please, do not mislead people. You run this app with software OpenGL
> on a device with really weak CPU. Xorg alone eats all resources of RPi 1 as
> it has no HW GPU acceleration.
> In my company we get 20-25 fps when rendering maps on a quite powerful
> (for embedded world) x86 and like 230% CPU usage (of 4 cores) as there is
> no linux driver for its GPU. Meanwhile - we get stable 60fps on i.MX6
> DualLite (2 ARMv7 cores 792MHz) with 12-20% CPU usage. All done with
> QtQuick.
>
>
>> Nasty worthless resource pig which exists only to pursue script kiddies.
>>
>> On 10/19/2017 04:38 AM, Vlad Stelmahovsky wrote:
>>
>> QML is not that resource hogging as JS. dont use JS and you'll be fine
>>
>> On Tue, Oct 17, 2017 at 8:11 PM, Roland Hughes <
>> roland at logikalsolutions.com> wrote:
>>
>>>
>>>
>>> On 10/17/2017 12:54 PM, interest-request at qt-project.org wrote:
>>>
>>> On ter?a-feira, 17 de outubro de 2017 08:11:13 PDT Roland Hughes wrote:
>>>
>>> The bug tracking system is under our control - it will not just
>>> disappear (from our perspective).
>>>
>>> Oh yes it will!
>>>
>>> Speaking as someone who has heard that soooooo many times before, let's
>>> just count a few for Qt shall we.
>>>
>>> The Trolltech bug database was never going to just disappear (from our
>>> perspective). It did. A tiny fraction of the bugs migrated to the new
>>> system but most were mass exterminated with
>>>
>>> The TT TT was not a public database. It existed internally only. When we
>>> switched to a public bugtracker, we could only export some entries since many
>>> had confidential customer information. Those that were exported had to be
>>> review by a person to make sure we were not violation any NDAs or
>>> confidentiality.
>>>
>>> That's the same reason why the code repository starts with Qt 4.5, not earlier
>>> versions.
>>>
>>>
>>> "The version this bug is reported against is no longer supported..."
>>>
>>> The Nokia bug tracker was never going to just disappear (from our
>>> perspective). It did. Few, if any of the older bugs made it into the
>>> current database. Most were mass exterminated with
>>>
>>> There was no Nokia database. We switched straight from the internal tdb
>>> (that's what it was called) to JIRA.
>>>
>>> There was a Nokia bug base as well, at least for a while. I and others
>>> entered bugs into it back in the day. Your argument also re-enforces a
>>> great many bugs "simply disappeared."
>>>
>>> I hear from quite a few companies in similar boats. They started
>>> development for a medical/industrial device which had a lengthy
>>> testing/approval process, filed bug reports for that version only to see
>>> them rot or fall victim to a mass extermination.
>>>
>>> Most open source projects don't support old versions, since they don't have
>>> the manpower to do so.
>>>
>>>
>>> The current owners of Qt and the current OpenSource maintainers don't
>>> offer or seem to understand the concept of an LTS (Long Term Support)
>>> version. They are constantly pursuing script kiddies and that worthless
>>> QML instead of maintaining the base which built them. This will soon
>>> force a fork in the OpenSource project. One which rips out all of the
>>> QML and focuses on nothing but bug fixes for 12 years. Yes, 12 years.
>>>
>>> Again, offence taken.
>>>
>>> Take all of the offense you want. Medical devices and industrial
>>> controls need LTS versions, not resource hogging QML features. Qt's chasing
>>> of the idiot phone market which has 6 months at best life spans is
>>> alienating and chasing away the very industries which made Qt successful.
>>>
>>> I don't know who plans on forking. There's no such division in the community,
>>> so any attempt to do so will probably start with very few developers. Almost
>>> certainly, fewer than critical mass to maintain the codebase.
>>>
>>> See TQt (Trinity Project) for an example of a fork attempt.
>>>
>>> It's easy to fork something you have been maintaining internally for
>>> years. There _IS_ such a division. You don't know about it because they
>>> don't come here. They justifiably believe they've been abandoned. The
>>> relentless pursuit of "new cool features" to please the phone crowd is
>>> causing the much larger medical device and industrial control industries to
>>> create their own LTS.
>>>
>>> How many questions have you seen on here over the past 18 months about
>>> Qt 3? That project Harmman (sp?) calls about periodically sells north of a
>>> million units per year and the company is maintaining Qt 3 on its own so
>>> they can make minor product enhancements which don't have to go though
>>> multi-year clinical trials. They aren't the only calls I get about products
>>> using Qt 3, 4.2, and the most likely soon to be orphaned (if not already)
>>> 4.8. Every company I am contacted about using earlier versions has their
>>> own staff maintaining the code base today. They have had no other choice.
>>> If anything, joining forces with someone who is not a competitor but using
>>> the same tool set will lighten their load.
>>>
>>> --
>>> Roland Hughes, President
>>> Logikal Solutions(630)-205-1593 <%28630%29%20205-1593>
>>> http://www.theminimumyouneedtoknow.comhttp://www.infiniteexposure.nethttp://www.johnsmith-book.comhttp://www.logikalblog.comhttp://www.interestingauthors.com/bloghttp://lesedi.us/http://onedollarcontentstore.com
>>>
>>>
>>> _______________________________________________
>>> Interest mailing list
>>> Interest at qt-project.org
>>> http://lists.qt-project.org/mailman/listinfo/interest
>>>
>>>
>>
>>
>> --
>> Best regards,
>> Vlad
>>
>>
>> --
>> Roland Hughes, President
>> Logikal Solutions(630)-205-1593 <%28630%29%20205-1593>
>> http://www.theminimumyouneedtoknow.comhttp://www.infiniteexposure.nethttp://www.johnsmith-book.comhttp://www.logikalblog.comhttp://www.interestingauthors.com/bloghttp://lesedi.us/http://onedollarcontentstore.com
>>
>>
>> _______________________________________________
>> Interest mailing list
>> Interest at qt-project.org
>> http://lists.qt-project.org/mailman/listinfo/interest
>>
>>
>
> --
> Roland Hughes, President
> Logikal Solutions(630)-205-1593 <(630)%20205-1593>
> http://www.theminimumyouneedtoknow.comhttp://www.infiniteexposure.nethttp://www.johnsmith-book.comhttp://www.logikalblog.comhttp://www.interestingauthors.com/bloghttp://lesedi.us/http://onedollarcontentstore.com
>
>
>


-- 
Best regards,
Vlad
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