Re: Change set based shallow clone

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On Sun, 10 Sep 2006, Jon Smirl wrote:
> 
> Is the kernel mapped into user processes using huge pages?

Yup. Huge pages and global. So the kernel should have fairly low TLB 
impact (depending on CPU - the kernel also has less locality than user 
space, since the data structures are all over the place, and some CPU's 
have very few hugepage entries. System code generally tends to have much 
worse I$ and TLB behaviour than most user apps, but at least the hugepage 
mappings tend to mitigate the TLB side somewhat).

> Another thing that should be mapped with huge pages is the video RAM.

I doubt it ends up being a huge deal in most cases. If you don't use the 
graphics chip to access video RAM with accelerated methods, the TLB is the 
_least_ of your worries. Going over the PCI bus (even with PCI-X etc) is 
the real problem.

There's a reason you want to do acceleration even in 2D..

		Linus
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