Re: AGP and PAT (induced?) problem (on AMD family 6)

From: Ingo Molnar
Date: Tue Aug 19 2008 - 06:27:29 EST



* Rene Herman <rene.herman@xxxxxxxxxxxx> wrote:

> On 15-08-08 17:24, Rene Herman wrote:
>
>> On 15-08-08 16:22, Ingo Molnar wrote:
>>
>>> (more people Cc:-ed)
>>
>> Thank you. Additional information at http://lkml.org/lkml/2008/8/6/449
>>
>>> agreed - +12 seconds wait suggest some rather fundamental breakage.
>>> Did we go back to uncached for some critical display area that makes
>>> X start up (shut down) that slowly? Did we mark the BIOS uncacheable
>>> perhaps, causing X to execute BIOS code very slowly?
>>
>> Quite a lot "uncached-minus" in those lists. I am desperately trying to
>> avoid a clue about mostly anything graphics related so, "I dunno".
>>
>> I haven't just disabled PAT yet (although I was about to just do so)
>> and am available for testing.
>
> <waiting with bated breath>
>
> Additional observation with respect to first,next shutdown:
>
> With Option "AGPSize" "64", and booted with "nopat", X startup (from
> startx<enter> to functional desktop) is approximately 5 seconds,
> shutdown is 1 second as calibration times.
>
> Booted without "nopat", X startup seems to alternate between 10+ and
> 16+ seconds and for shutdown -- the first shutdown after boot takes
> some 14 seconds total, subsequent shutdowns settle at around 5
> seconds.

would it be possible to start up and shut down X in the slow case via
strace, by doing something like this:

strace -f -ttt -TTT -o trace.log startx

and see which system calls (or other activities) took suspiciously long?

Ingo
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