More Speed with QT?

[cipri]

Edited

[chaley]

Uhhhh.... Qt is a graphics toolkit, not a programming language.

What language are you suggesting be used for the logic (database code, device interfaces, content server, etc)? Because you mention HAIKU, it is probably C++.

Rewriting calibre in C++ would be a multi-person-year effort. In the end, we would have something that might or might not be appreciably faster, but *would* be harder to maintain, harder to develop, and harder to debug. Hard to see why this would be a good thing, but perhaps I am confused.

[DiapDealer]

but *would* be harder to maintain, harder to develop, and harder to debug.

Not to mention harder to customize, and harder to write plugins for.

Being able to run Calibre from source is one of the biggest advantages that the newbie developer has at their disposal. You can literally be hacking and prodding within minutes.

Plus, the option to port a "Speedy C" version of Calibre is available to anyone who feels motivated in that regard.

[cipri]

Edited

[kovidgoyal]

IMNSHO if calibre were in C/C++ it would be about 1/10th as capable as it is now, it would develop at 1/10 the speed and most probably I would have moved on to doing other things by now.

That said, if you want to improve the speed of calibre, do some profiling, find the bottlenecks. Once you do, it is always possible to write C extensions to speed them up.

calibre currently has about half a dozen extensions written in C to speed up certain operations.

[kovidgoyal]

Sigh, yet another silly loop speed test. These are completely irrelevant to real world application performance.

[QUOTE=cipri;1240208]

Originally Posted by chaley

Rewriting calibre in C++ would be a multi-person-year effort. In the end, we would have something that might or might not be appreciably faster/QUOTE]

Look here at a comparision between the language Python and Cobra.
The result is devastating.

http://cobra-language.com/forums/vie...2&hilit=python

Here you see that in some cases Cobra can be hundrets of times faster than python.
I don't know both languages, because use exclusively c++, but the comparision between cobra and python, showes me that it could bring a lot of speed to have calibre written in c++, using QT.

python might be suitable for little programs, but calibre has to do a greater job.

And c++ is not always hard to maintain, it depends on the quality of the design.

[chaley]

Originally Posted by cipri

Look here at a comparision between the language Python and Cobra.
The result is devastating.

http://cobra-language.com/forums/vie...2&hilit=python

Note that in that 'benchmark', the variable x is not used. Any C++ optimizer would remove the assignment, then remove the expression because it isn't used, then remove all the loops because their indices aren't used, leaving the null program. No surprise that doing nothing is a lot faster than doing anything.

If you want to do such a port, go for it. However, better would be to do as Kovid suggested: find bottlenecks and either report or (preferable) fix them. Some users have done similar things and helped improve performance by large factors. The latest one was demonstrating that file system performance on some systems is terrible, and that huge benefits could be obtained by caching results of the cover existence test (a file_exists test) in the DB.

[Evilwarning]

Hi

C/C++ will always be faster and i know depends on the programmer too but lets assume a good programer. This is the reason we write games and OS's in these languages, performance. They have two major drawbacks, heavily typed and hard to debug.

Maybe would be good to make some improvements but sometime rewrite is not the best option. I think the major step would be the use of a JIT like pypy, this would keep the easiness of coding with the performance of a compiled language.

My 2 cents

[Manichean]

Wow. I wonder what all the people creating these threads would've said if they'd experienced Calibre before the drastic speedups of recent versions...