Messages in this thread | | | Subject | Re: [PATCH 1/10] Cr4 is valid on some 486s | From | Arjan van de Ven <> | Date | Mon, 14 Nov 2005 21:52:46 +0100 |
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> > Runtime tricks that increase complexity cost, yes. It's all a question > of measured gain vs. complexity. But a couple of percent gained on an > overall basis can be magnified enormously if you are looking at a > workload that stresses a particular path.
a couple of percents sounds really really high to me. If it's really that then I think Andi's conclusion is wrong with respect to that locking cliff; if we spend a few percent of our performance on locks in the uncontended case we're way over the edge in my opinion.
> I would expect some of those > gains to be non-trivial, especially if considering the optimizations you > could do on page table updates knowing you needn't worry about SMP
page table updates happen in the hypervisor in a xen like paravirtualized setup right? so that happens outside the kernel..
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