On Thu, 2005-02-03 at 22:26 -0800, Christoph Lameter wrote: > On Fri, 4 Feb 2005, Paul Mackerras wrote: > > > As has my scepticism about pre-zeroing actually providing any benefit > > on ppc64. Nevertheless, the only definitive answer is to actually > > measure the performance both ways. > > Of course. The optimization depends on the type of load. If you use a > benchmark that writes to all pages in a page then you will see no benefit > at all. For a kernel compile you will see a slight benefit. For processing > of a sparse matrix (page tables are one example) a significant benefit can > be obtained.
If you have got to the stage of doing "real world" tests, I'd be interested to see results of tests that best highlight the improvements. I imagine many general purpose server things wouldn't be helped much, because they'll typically have little free memory, and will be continually working and turning things over. A kernel compile on a newly booted system? Well that is a valid test. It is great that performance doesn't *decrease* in that case :P Of course HPC things may be a different story. It would be good to see your gross improvement on typical types of workloads that can best leverage this - and not just initial ramp up phases while memory is being faulted in, but the the full run time. Thanks, Nick - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/