[CentOS] CentOS 4.4 smp on Dual Quad Core Xeon
John Summerfield
debian at herakles.homelinux.org
Mon Feb 26 22:52:46 UTC 2007
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
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