1GHz is SLOW??? No, the 1GHz machines I have used were faster that the current Core2something hype lately.
The currently used single cored CPU at 1.3GHz runs happily at 80 kHz interrupts driving stepper quadrature outputs at insane speeds, something I was not able to think about with a 3GHz CPU. It's all about the latencies and optimisations for those. I doubt it is a solely compiler bug, it is a feature - and "misalignment of compilation parameters" is a good term. Some options don't work with something. I recently tried to compile a kernel of something and it would not let me do the whole thing with -O3 in no way... some program/kernel parts are written in some way they are and it is not easy to simply tell them to be recompiled in a non-intended manner. Even with the programs that did work, I had to spend some time studying the compiler directives on hundred of pages as to where put what and why and why not. And Speed, Power and Latency are 3 dirrerent terms with completely different meanings. I have seen people lately complaining that the Core2Duo computers are slow.. while in terms of processing power they are better than the previous generation. On 11/9/07, Lorenzo Marcantonio <[EMAIL PROTECTED]> wrote: > On Fri, 9 Nov 2007, Mario. wrote: > > > No, standard optimisation is -O2, the -O3 is unrolling all loops so > > that CPUs do less guessing and more crunching more like a RISC. > > There is more about the K7 opts... pplus there is some errata teh > > compiler may need manually be notified of. The K7 has also some power > > management, you want probably to disable it in the kernel too. Some > > bugs manifest as a combination of a specific code features, compiler > > features and processor features. > > > > And BTW, there is this 586 and i686 processor option difference, are > > you sure you want to have 586 only? (without MMX etc...) > > gcc using mmx is famous for giving up because it has too few registers to > work with :P > > Maybe I could do some more research but recompiling all the kernel, rtai and > emc2 even with 1GHz it's a little slow... > > And it gives the problem both with gcc 4.0.2 and 4.2.2. So if someone else > want to make a tailored system like myself, should be aware of there > 'troubles' (nasty stuff: inserting a rtapi_print between some assignment > makes it work because it interrupts the flow of the optimizer). > > Still, it would be useful to know if it's a compiler bug or just some > misalignment in compilation parameters... > > > ------------------------------------------------------------------------- > This SF.net email is sponsored by: Splunk Inc. > Still grepping through log files to find problems? Stop. > Now Search log events and configuration files using AJAX and a browser. > Download your FREE copy of Splunk now >> http://get.splunk.com/ > _______________________________________________ > Emc-developers mailing list > Emc-developers@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-developers > ------------------------------------------------------------------------- This SF.net email is sponsored by: Splunk Inc. Still grepping through log files to find problems? Stop. Now Search log events and configuration files using AJAX and a browser. Download your FREE copy of Splunk now >> http://get.splunk.com/ _______________________________________________ Emc-developers mailing list Emc-developers@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-developers
