At 2004-10-01T12:54:02+1200, Volker Kuhlmann wrote:
> Hyperthreading models appear as 2 CPUs, that's the idea. You may need a
> multi-processor kernel too, to make proper use of the feature.
At 2004-10-01T12:53:43+1200, Nick Rout wrote:
> idle question (as i don't have a HT'ing P4) - do you need to run SMP
> to get it working properly?
Yes, an SMP enabled kernel is required to take advantage of both logical
processors.
Whether there's any performance gain to be had is debatable... it
largely depends on the workload that you throw at it.
An interesting thing about Linux is that the uniprocessor kernel has a
lot of locking that is required for SMP conditionally compiled out, so
you don't pay for that locking on a uniprocessor machine with a
uniprocessor kernel.
At 2004-10-01T12:54:02+1200, Volker Kuhlmann wrote:
> It's probably the flag "ht" in the flags line of cpuinfo.
Partially. A CPU that advertises the 'ht' flag does not necessarily
support hyperthreading--you also need support from the BIOS and the
motherboard chipset. Early 2.4GHz-ish Pentium 4 models advertised the
'ht' flag, but did not have a working hyperthreading implementation.
Cheers,
-mjg
--
Matthew Gregan |/
/| [EMAIL PROTECTED]
