On 7/29/05 10:46 AM, "Josh Berkus" <josh@agliodbs.com> wrote: >> does anybody have expierence with this machine (4x 875 dual core Opteron >> CPUs)? > > Nope. I suspect that you may be the first person to report in on > dual-cores. There may be special compile issues with dual-cores that > we've not yet encountered.
There was recently a discussion of similar types of problems on a couple of the supercomputing lists, regarding surprisingly substandard performance from large dual-core opteron installations. The problem as I remember it boiled down to the Linux kernel handling memory/process management very badly on large dual core systems -- pathological NUMA behavior. However, this problem has apparently been fixed in Linux v2.6.12+, and using the more recent kernel on large dual core systems generated *massive* performance improvements on these systems for the individuals with this issue. Using the patched kernel, one gets the performance most people were expecting. The v2.6.12+ kernels are a bit new, but they contain a very important performance patch for systems like the one above. It would definitely be worth testing if possible. J. Andrew Rogers ---------------------------(end of broadcast)--------------------------- TIP 5: don't forget to increase your free space map settings
