John R Pierce wrote: > Morten Torstensen wrote: >> Tru Huynh wrote: >>> [tru at quadcore ~]$ uname -a >>> Linux quadcore 2.6.9-42.0.3.ELsmp #1 SMP Fri Oct 6 06:28:26 CDT 2006 >>> x86_64 x86_64 x86_64 GNU/Linux >>> [tru at quadcore ~]$ grep -A4 processor /proc/cpuinfo >>> processor : 0 >> >> Just take care with more than 8 CPUs, because you need the largesmp >> kernel then. Worked on a 8 socket, 16 CPU system where that was a pain >> due to binary kernel modules. >> >> Now those machines could be 32 CPU systems... and you could add 8 >> sockets more. 64 CPUs on Intel platform with commodity hardware. Not >> that many years ago that would have been utopia :) >> > > > I believe those quad core Xeon "Clovertown" CPUs support hyperthreading > too. which means 2 of them has 16 execution threads if you've enabled > hyperthreading in the BIOS. While many people denigrate > hyperthreading, we've got some Java messaging/database/middleware stuff > that gets a HUGE boost on a older dual xeon* with HT enabled... this is > with 2.8Ghz, 533Mhz FSB, 512K cache Xeons of this flavor: I was astonished at the results of running this on an HT system: #!/usr/bin/perl #use integer; $i = 0; while ($i < 10000) { $j = 0; while ($j < 10000) { ++$j; } ++$i; } [summer at bilby ~]$ More precisely, two of them together: time bin/bm.perl&time bin/bm.perl I don't think anything written in Perl is very cache-friendly, but the HT system performed about as I'd expect dual-core to. -- Cheers John -- spambait 1aaaaaaa at coco.merseine.nu Z1aaaaaaa at coco.merseine.nu Please do not reply off-list