John R Pierce wrote:
Morten Torstensen wrote:
Tru Huynh wrote:
[tru@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@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@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.