Moin,
On Thu, 26 Jul 2007 14:07:47 -0700
"Timothy Normand Miller" <[EMAIL PROTECTED]> wrote:
> Thanks to some helpful people on the list, we were able to figure out
> why in our test environment, framebuffer writes were slow. We changed
> the way the mapping worked to enable write combining, and it now gets
> very good throughput.
Could you explain what you did? For reference and to stanch my
curiosity :)
> But we've since noticed that READS only get
> about 4 megabytes/sec. Does anyone have any insight into this?
> Surely, there must be some way to enable an optimization to reads as
> well, no?
Have you set the "prefetchable" bit in the base address registers?
To my understanding, if that is set, read operations should always
get one cacheline.
Alternatively use memcpy_fromio(), though i doubt that this does
more than 4 byte reads.
Attila Kinali
--
Praised are the Fountains of Shelieth, the silver harp of the waters,
But blest in my name forever this stream that stanched my thirst!
-- Deed of Morred
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