Re: how much mem to give postgres?

On Wed, Oct 20, 2004 at 03:07:00PM +0100, Matt Clark wrote:

> You turn it off in the BIOS.  There is no 'other half', the processor is
> just pretending to have two cores by shuffling registers around, which
> gives maybe a 5-10% performance gain in certain multithreaded
> situations.


> <opinion>A hack to overcome marchitactural limitations due
> to the overly long pipeline in the Prescott core.</opinion>.  Really of
> most use for desktop interactivity rather than actual throughput.

<OT>
Hyperthreading is actually an excellent architectural feature that
can give significant performance gains when implemented well and used
for an appropriate workload under a decently HT aware OS.

IMO, typical RDBMS streams are not an obviously appropriate workload,
Intel didn't implement it particularly well and I don't think there
are any OSes that support it particularly well.
</OT>

But don't write off using it in the future, when it's been improved
at both the OS and the silicon levels.

Cheers,
  Steve