Messages in this thread | | | Date | Wed, 28 Mar 2007 13:45:11 -0700 | From | Andrew Morton <> | Subject | Re: [RFC] i386: Remove page sized slabs for pgds and pmds |
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On Wed, 28 Mar 2007 13:12:56 -0700 (PDT) Christoph Lameter <clameter@sgi.com> wrote:
> The benefit of preconstructed pgds and pmds in the i386 arch code seem to > be debatable. The performance measurements indicate that there may be a slight > benefit but it seems to almost vanish in the noise ratio.
yeah, I did a couple hours testing with rc5, rc5+quicklists, rc5+quicklists+qlhack, where "qlhack" is my patch which removes the quicklists and mysteriously causes i386 to crash.
I was testing 8-way x86_64 with patch-scripts (wildly fork-intensive), kernel build and lmbench.
Basically I was unable to observe any statistically meaningful-looking differences between any of them.
I would like to test qlhack on ia64, because ia64 puts pte-pages into the quicklists as well, but my ia64 machine is presently indisposed.
My (much) preferred way to handle all this is to remove the quicklists from all architectures: just use alloc_page() and free_page() for pte pages, pmd pages, etc. I remain unaware of any testing whcih indicates that this would be a bad change.
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