Opteron kernel

Greg Lindahl lindahl at pathscale.com
Tue Nov 25 18:21:49 EST 2003


On Tue, Nov 25, 2003 at 03:05:55PM -0500, Donald Becker wrote:

> The easiest performance improvement comes from proper memory DIMM
> configuration to match the application layout.  Each processor has its
> own local memory controller, and understanding how the memory slots are
> filled and the options e.g. interleave can make a 30% difference on a
> dual processor system.

I second this -- don't trust what you think you *know* (we all know it
only has 1 memory channel, so you shouldn't have to fill all the dimm
slots) and instead measure (filling all the dimms slots helps perf.)

The 2.6 kernels have a bit better performance than 2.4, and there are
bugs that simply aren't fixed in 2.4, including one that our compiler
stomps on frequently.

You will definitely want the "runon" command for processor affinity...
but it will change your choice of interleave in the BIOS.

-- greg


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