DragonFly BSD
DragonFly bugs List (threaded) for 2004-05
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Re: can't boot with kern.mmxopt=1

To: Matthew Dillon <dillon@xxxxxxxxxxxxxxxxxxxx>
From: Richard Nyberg <rnyberg@xxxxxxxx>
Date: Tue, 04 May 2004 09:04:22 +0200

At Mon, 3 May 2004 20:21:44 -0700 (PDT),
Matthew Dillon wrote:
>     If we can verify that (hopefully) it was the critical enter/exit
>     code in the assembly that was the cause of your boot-time lockup,
>     I have a real fix all ready to go which moves the on-stack allocation
>     to the globaldata structure and is also able to remove the fninit that
>     was in bcopy's critical path (which costs 50ns on an AMD64 box) by 
>     guarenteeing that the fpu is left in a normally useable mode by the
>     kernel once the app's state has been saved off.  All in all I can
>     greatly reduce the FP setup time in the kernel bcopy and eek out 
>     another 100MB/s in peak performance (on the AMD64 Athlon 3200+) with
>     these changes.

Sorry! It still hangs in the same place. I tried to break to DDB but
nothing happened. I even had to pull the plug to turn it off!

I'll try your first patch this afternoon. However if it hangs and I
_can_ break to DDB, I'm still not sure what to look for and how. Could
you give some hints?

Can you set the dumpdev from the loader? In that case maybe I could
generate a core dump for you to look at. If that would be of interest.

Anyway, hopefully it works and I don't have to dance with DDB.


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