[ale] CPU question, dual core?

[Greg Freemyer]

Jim,

Hyper-threading is like 1.5 CPUs.  IIRC, the CPU itself has only one
main processing unit, but 2 instruction streams and 2 level-1 caches.
If the processing unit stalls retrieving data from the active level-1
cache it immediately switches instruction streams/caches and starts
executing the alternalte instruction stream.  Not as good as 2 full
CPUs, but you don't have processor stalls near as often when
retrieving data.

I believe the net result is you should use a SMP kernel to drive a
hyperthreading CPU.

Greg

On 6/29/06, Jim Popovitch <jimpop at yahoo.com> wrote:
> I lease a few servers from here and there.  A new one that I just got
> showed more than 1 CPU in the bootlog (WARNING: NR_CPUS limit of 1
> reached) so I installed an smb kernel and wallah, it boots and finds 2
> CPUs.  I run several virtual systems on this host, and the smb kernel
> seems to have doubled the system's capabilities and performance (from my
> 10,000ft view).  However, hwdata shows the motherboard to be an Asus
> P4P800-VM (http://www.dealtime.com/xPF-Asustek_P4P800_VM) which is a 1
> cpu board. /proc/cpuinfo shows both CPUs as
>    vendor_id       : GenuineIntel
>    cpu family      : 15
>    model           : 4
>    model name      : Intel(R) Pentium(R) 4 CPU 3.00GHz
>
> I believe this to be an Intel Hyper-Threading CPU, but I slept though
> discussions of those CPUs over the past few years.  So, is this a
> dual-core CPU?  Is an smb kernel the right kernel for such?
>
> Tia,
>
> -Jim P.
> _______________________________________________
> Ale mailing list
> Ale at ale.org
> http://www.ale.org/mailman/listinfo/ale
>


-- 
Greg Freemyer
The Norcross Group
Forensics for the 21st Century