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Mac Forum / Programming / CodeWarrior / December 2005CW 10 has a better optimiser ?
Hi, I've seen a couple of people say that CW 10 has given their processor intensive code quite a boost. Can anyone confirm this ? My app is a renderer, so it's about as processor intensive as they come. The current version is CFM and still supports OS 9, and it's not going to be updated for Intel ( we have a brand new app superceding it, which is Mach-O and Universal ). If CW 10 does provide a bit of performance boost I would be happy to drop $99 for it and recompile my app to save my users some time. Regards, Jo Meder > Hi, > [quoted text clipped - 5 lines] > Universal ). If CW 10 does provide a bit of performance boost I would be > happy to drop $99 for it and recompile my app to save my users some time. It's not quite as simple as one optimizer being better/worse than another - it depends greatly on the nature of the code that's being optimised. But yes, there are still certain cases where CW can beat gcc (although gcc 4.0 has closed this gap considerably). You're probably only looking at say ~10% best case versus gcc 3.3, and there may even be some routines where gcc does better than CW. So the bad news is that you really need to try both compilers with your code and see if there's any significant difference. You might also want to take a look at IBM's xlc if you really need to squeeze avery last ounce of performance out of your code. Paul > > I've seen a couple of people say that CW 10 has given their processor > > intensive code quite a boost. Can anyone confirm this ? My app is a [quoted text clipped - 8 lines] > optimised. But yes, there are still certain cases where CW can beat gcc > (although gcc 4.0 has closed this gap considerably). I think the OP's question is whether it is worth his while upgrading from an earlier version of CodeWarrior to version 10 for the extra optimisation it might give. I don't know about the optimisation but would remind any prospective buyer that CW 10 for Macintosh is sold without support and will not be updated further. So you will have to work around any bugs you find on your own account. Alwyn > I think the OP's question is whether it is worth his while upgrading > from an earlier version of CodeWarrior to version 10 for the extra [quoted text clipped - 4 lines] > updated further. So you will have to work around any bugs you find on > your own account. Ah - mea culpa - I wasn't paying enough attention and assumed the OP was asking about CW versus gcc. In that case I doubt that he'll see any performance difference with CW 10. I haven't noticed much improvment in code optimization in CW since it peaked at around version 5.3. Paul My program, Bugs On The Run (available with source code on versiontracker), runs 2x faster with CW10 than with CW8.3 or xcode 2.2 for the core algorithm. However, in graphics intensive mode it runs 2x faster in xcode than with CW10, and the same speed between CW8.3 and CW10. If you download it - you can directly compare the CW10 version with the xcode version, since the projects are included along with others (CFM, Mach-o, etc). Noam > My program, Bugs On The Run (available with source code on > versiontracker), runs 2x faster with CW10 than [quoted text clipped - 4 lines] > the xcode version, since the projects are included along > with others (CFM, Mach-o, etc). Are you using gcc 3.3 or 4.0 with Xcode 2.2 ? Paul I use GCC 4.0. Noam > I use GCC 4.0. I profiled your code with Shark and it looks like 90% of the time is spent in QD/Quartz, so I'm not sure how the compiler can make much difference ? Paul Maybe the carbon libraries which QD uses is different and therefore more optimized in one case rather than the other. (in CW vs. xcode). Noam > Maybe the carbon libraries which QD uses is different and therefore > more optimized in one case rather than the other. (in CW vs. xcode). I wouldn't have thought so - they're just the standard frameworks, no ? Anyway, one thing you could do to speed up your app is to reduce the amount of drawing that you do. There's no point trying to redraw your window more than, say, 10 or 20 times a second - the human eye can't perceive the difference. So you could keep track of the last window update time and only update the window if the elapsed time is greater than some threshold (e.g. 50 ms). That should help performance a lot in the faster modes (e.g. "Turbo", where it looks like you're trying to redraw at around 200 fps even on my lowly G4 Powerbook). Regards, Paul I just found out that I used the 10.3.9 SDK path in the CW version - (fast hyper, slow turbo), and the 10.4u target SDK in my xcode version (fast turbo, slow hyper). If I exchange the SDKs in either CW or xcode I get consistent results. The bottom line is that it all depends on the SDK path: to get fast hyper - use the older 10.3.9 SDK, and to get faster turbo use the 10.4u SDK. Otherwise the two compilers CW and GCC 4.0 give exactly the same results. (for those who don't know hyper = core algorithm at max speed, turbo =fastest graphics (QD) speed). About the refresh rate, you can adjust it via the slider or preferences. Of course I could have decided to draw only once every few iterations and thereby achieve more iterations per second at the expense of fewer graphic frames per second, and may do so as an option in a future release. Thanks for the ideas. Noam Hi Noam, > I just found out that I used the 10.3.9 SDK path in the CW version - > (fast hyper, slow turbo), and the 10.4u target SDK in my xcode > version (fast turbo, slow hyper). If I exchange the SDKs in either > CW or xcode I get consistent results. I think these is some kind of optimisation in the graphics stuff, coalesced updates or something, which is only enabled when you link to a certain version of the SDKs. I don't remember the exact details, but I think it was discussed on the Apple carbon-dev list. Regards, Jo Meder > Hi Noam, > [quoted text clipped - 11 lines] > > Jo Meder Thanks for the info, Jo. I will look it up. Noam > My program, Bugs On The Run (available with source code on > versiontracker), runs 2x faster with CW10 than [quoted text clipped - 4 lines] > the xcode version, since the projects are included along > with others (CFM, Mach-o, etc). That's VERY interesting data. Thanks for posting it.  SignatureSteven Fisher; sdfisher@spamcop.net You're welcome. |
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