Re: HPPA and Squeeze

[dann frazier <dannf@dannf.org>]

On Mon, Jul 06, 2009 at 09:47:09PM -0400, John David Anglin wrote:
> > If I remember correctly, there's still some issues with the L2 cache on
> > pa8800 that we haven't quite bothered to work out yet, since it's "good
> > enough" for now. James probably knows more. It would be interesting to
> > see if you could reproduce it with a UP 64-bit kernel on your C3750 to
> > discount the L2 problems.
> 
> Googling, I see Grant had trouble with RCU_TORTURE_TEST=y.  Probably,
> I should test current kernel to see if the problem is still present.
> 
> I guess you are referring to this change:
> http://fossplanet.com/linux.debian.devel.kernel.cvs/thread-4378354-r7141-patches/
> 
> I'm thinking we must be missing a flush...  Maybe in clear_user_page
> as for copy_user_page?
> 
> Do the problematic debian buildd machines have pa8800/pa8900 processors?

dannf@penalosa:~$ cat /proc/cpuinfo 
processor	  : 0
cpu family	  : PA-RISC 2.0
cpu 		  : PA8700 (PCX-W2)
cpu MHz		    : 750.000000
model		      : 9000/785/J6700
model name	      : Duet W2
hversion	      : 0x00005dd0
sversion	      : 0x00000491
I-cache		      	: 768 KB
D-cache			  : 1536 KB (WB, direct mapped)
ITLB entries		  : 240
DTLB entries		  : 240 - shared with ITLB
bogomips		  : 1495.04
software id		  : 2001606322


> My sense is that some change (probably to the core memory management
> code) made the coherence issue worse post 2.6.22.x.
> 
> Dave

-- 
dann frazier