Re: Linux v.s. Mac OS-X Performance

On 11/13/07 10:02 AM, "Scott Ribe" <scott_ribe(at)killerbytes(dot)com> wrote:

> What you're referring to must be that the kernel was essentially
> single-threaded, with a single "kernel-funnel" lock. (Because the OS
> certainly supported threads, and it was certainly possible to write
> highly-threaded applications, and I don't know of any performance problems
> with threaded applications.)
>
> This has been getting progressively better, with each release adding more
> in-kernel concurrency. Which means that 10.5 probably obsoletes all prior
> postgres benchmarks on OS X.

While I've never seen this documented anywhere, it empirically looks like
10.5 also (finally) adds CPU affinity to better utilize instruction caching.
On a dual CPU system under 10.4, one CPU bound process would use two CPU's
at 50%. Under 10.5 it uses one CPU at 100%.

I never saw any resolution to this thread - were the original tests on the
Opteron and OS X identical, or were they two different workloads?

Wes