Re: shared pagetable benchmarking

[William Lee Irwin III <wli@holomorphy.com>]

On Fri, Dec 20, 2002 at 03:11:09AM -0800, Andrew Morton wrote:
> Did a bit of timing and profiling.  It's a uniprocessor
> kernel, 7G, PAE.
> The workload is application and removal of ~80 patches using
> my patch scripts.  Tons and tons of forks from bash.
> 2.5 ends up being 13% slower than 2.4, after disabling highpte
> to make it fair.  3%-odd of this is HZ=1000.  So say 10%.
> Pagetable sharing actually slowed this test down by several
> percent overall.  Which is unfortunate, because the main
> thing which Linus likes about shared pagetables is that it
> "speeds up forks".
> Is there anything we can do to fix all of this up a bit?

For testing purposes, try removing the opportunistic mmap()-time
sharing.


Bill
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