Re: 4MB pages and framebuffer access, x11perf results, 2.1.125

Linus Torvalds (torvalds@transmeta.com)
30 Oct 1998 05:24:27 GMT


In article <Pine.LNX.3.96.981030013315.13731A-100000@chiara.csoma.elte.hu>,
MOLNAR Ingo <mingo@chiara.csoma.elte.hu> wrote:
>
>Correct :( without the GLOBAL flag, the numbers are almost identical, only
>slight improvement for the 4M version, not worth to mention. Sorry, this
>really was unintentional ... :( It's amazing though how much difference
>this made.

This makes much more sense.

I was really surprised by the 15% increases, they sounded impossible on
any real modern hardware (any reasonable modern graphics hardware tends
to not need all that much CPU access, and the TLB doesn't matter for the
graphics card itself which certainly has direct access to all of its own
memory).

I can imagine that large pages made sense for older bitmapped devices
without hardware acceleration and with faster buses. But I think it's
an optimization that is no longer very relevant as most of the real
video activity happens on the graphics hardware these days.

Linus

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