Philip Covington wrote: > On 10/11/06, Jim Lux <[EMAIL PROTECTED]> wrote: > >> At 06:44 AM 10/11/2006, Jim, W4ATK wrote: >> >>> Phil Covington wrote: >>> >>> "A lot of the perceived need for threading goes away when you get away from >>> straight >>> line procedural code." >>> >>> As an OLD machine language programmer, I am of the impression that "straight >>> line" code increases the speed of the particular routine(s) avoiding those >>> heavy far calls and the resultant stack operations. I think most optimizers >>> that offer the choice of size and/or speed generate straight line objects as >>> a means of increasing the speed..... Perhaps my rather ancient experience is >>> mistaken.... >>> >> True in most cases. But, might be a case of optimizing for a >> resource which we have an excess of, by spending a resource we are short of. >> >> > > <snip> > > The interesting thing is that the JIT in .NET finds optimizations at > run time that could not easily be built into an optimizing compiler. > > I was pleasantly surprised when I could compute a FFT/IFFT in code > written in C# (based on Ooura's FFT code) as fast as using FFTW > library (even after running wisdom). If you look through the SharpDSP > source you'll see that I did not use FFTW. >
I suspect, but am not sure, that you ran these tests before we changed the internals over to float and used the SIMD variants in FFTW. It is very hard for me to imagine compiled code running faster than these hand optimized assembly "codelets". That would be VERY interesting to investigate if it is true. > 73 de Phil N8VB > > _ 73's Bob N4HY -- AMSAT Director and VP Engineering. Member: ARRL, AMSAT-DL, TAPR, Packrats, NJQRP, QRP ARCI, QCWA, FRC. ARRL SDR WG Chair "You see, wire telegraph is a kind of a very, very long cat. You pull his tail in New York and his head is meowing in Los Angeles. Do you understand this? And radio operates exactly the same way: you send signals here, they receive them there. The only difference is that there is no cat." - Einstein _______________________________________________ FlexRadio mailing list FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archive Link: http://www.mail-archive.com/flexradio%40flex-radio.biz/ FlexRadio Homepage: http://www.flex-radio.com
