Hi.
What might be faster? One more synchronization primitive in the code will
increase performance?
From: Romain Beaumont
Sent: Thursday, June 12, 2014 9:48 AM
To: Igor Mironchik
Cc: interest@qt-project.org
Subject: Re: [Interest] How to speed-up chameleons
It might not be necessary (ie you can use something else instead) but it might
be faster ;)
2014-06-12 8:22 GMT+02:00 <igor.mironc...@gmail.com>:
Hi.
First chameleon waits for another, i.e. he doing nothing while another will
not come to the meeting place. And here semaphore is not necessary.
Most slow place is QEventDispatcherWin32::processEvents()
From: Romain Beaumont
Sent: Wednesday, June 11, 2014 7:54 PM
To: Igor Mironchik
Cc: interest@qt-project.org
Subject: Re: [Interest] How to speed-up chameleons
"first chameleon should wait a second;" this sound like semaphore to me, but
I don't know this chameleon problem.
What part of Qt is causing it to be slow ? QThread ? the signal/slot ?
2014-06-11 18:51 GMT+02:00 <igor.mironc...@gmail.com>:
Hi.
What do you suggest?
From: Romain Beaumont
Sent: Wednesday, June 11, 2014 5:12 PM
To: Keith Gardner
Cc: igor.mironc...@gmail.com ; interest@qt-project.org
Subject: Re: [Interest] How to speed-up chameleons
Hi,
Why do you need to use Qt signals/slots ?
Isn't there something more appropriate to this task ?
2014-06-11 15:36 GMT+02:00 Keith Gardner <kreios4...@gmail.com>:
I have one question to you. Why new syntax of QObject::connect()
improve performance for a 5%.
I mean that if in code change
connect( sender, SIGNAL( signal() ), receiver, SLOT( slot() ) );
to
connect( sender, &Sender::signal, receiver, &Receiver::slot );
then code works faster... Why? May be somebody know the answer, I don’t
want to read Qt’s code for the answer on this question.
I would guess would be that the first connect is performing a string
lookup and validating the arguments at run time. SIGNAL and SLOT are taking
the macro parameters and turning them into character arrays.
The second connect is working with function pointers which allows for the
compiler validate their existence and ensure that the arguments are compatible
at compile time instead of run time.
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