[CentOS] CentOS 4.4 smp on Dual Quad Core Xeon

[Jay Lee]

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:
No "Core based" CPU that I've seen so far (Pentium M, Core, Core 2, Xeon 
51xx) can enable hyperthreading though they will have the ht flag show 
up in /proc/cpuinfo.  The ht flag though was present in every Pentium 4 
CPU, it is not a solid indicator that Hyperthreading can be turned on.  
Don't ask me why this is, ask Intel...

Jay