Re: [PATCH] Convert pgtable cache to slab

Robin Holt
2005-02-15T19:57:45Z

On Tue, Feb 15, 2005 at 11:46:21AM -0800, David Mosberger wrote:
> >>>>> On Tue, 15 Feb 2005 13:31:48 -0600, Robin Holt <holt@sgi.com> said:
>
> Robin> Is there a strong objection to implementing 4 levels of 16k
> Robin> page tables for now and then, if someone else sees a need,
> Robin> convert to using long page table format and adjust page
> Robin> tables as needed at that point in time.
>
> I certainly don't want to switch my machines to 4-levels. There is
> zero need for that on the machines I use, so why pay the overhead of
> an extra level?
>
> BTW: why do you want 4-level/16KB over 3-level/64KB?

There are two reasons that have been given to me.

The first is that most of the software vendors are only certifying
their applications to work on 16kb pages. This seems to follow what
the distributions are doing as well.

Additionally, we have seen that performance on certain file server
benchmarks are better with 16kb pages and expect that there will be a
continued demand by some of our customers to stay with 16kb pages.

Thanks,
Robin