Daniel Fischer wrote:
Am Freitag 19 März 2010 02:25:47 schrieb Xiao-Yong Jin:
It is one of those pathetic single core pentium4 with so called hyper-threading enabled.
'kay, but why does it say
processor : 0 ... processor : 1
Hyperthreading is explained here: http://www.pcstats.com/articleview.cfm?articleID=1302 As explained, two hyperthreads is not euqivalent to to CPU cores because the two hyperthreads share resources while 2 discrete cores do not. As I remember it, the performance of the Pentium 4s with HT never met up to the promise and that line was swiftly replaced by the Core 2 Duo range of CPUs which we actually quite good. As a rough and ready test, I compiled Ben Lippmeier's DDC compiler on the following CPUS: a) Intel(R) Pentium(R) 4 CPU 3.00GHz (2Meg cache) b) Intel(R) Core(TM)2 Duo CPU T9600 @ 2.80GHz (6Meg cache) Using the ghc-6.12.1 on both (32bit Ubuntu 10.04 chroot for the P4 and a 32bit Debian unstable chroot for the Core2Duo), compiling DDC took (using 'make clean ; time make'): a) 2m54.301s on the P4 HT b) 0m59.277s on the Core2Duo If nothing else, it shows that two CPUs with similar clock speeds and the same number of processors listed in /proc/cpuinfo can have vastly different performance characteristics. Erik -- ---------------------------------------------------------------------- Erik de Castro Lopo http://www.mega-nerd.com/