I thought he said that too, then I read it again, and he meant it's slow for compiling a kernel + rtai + etc...
and I agree that a faster machine reduces compile type.. (btw: you can compile on another machine and bring the binaries over). Regards, Alex ----- Original Message ----- From: "Mario." <[EMAIL PROTECTED]> To: "EMC developers" <emc-developers@lists.sourceforge.net> Sent: Friday, November 09, 2007 12:59 PM Subject: Re: [Emc-developers] emcmot lockup cause found > 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 > > > -- > No virus found in this incoming message. > Checked by AVG Free Edition. > Version: 7.5.503 / Virus Database: 269.15.26/1119 - Release Date: > 11/8/2007 5:55 PM > > ------------------------------------------------------------------------- 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
