Re: 7.0/6.2, 4GB and AHC

The AHC driver was personally tested with >4GB while it was in active
development, but it's certainly possible that bugs have crept in over
the years.  I'll test it when I get off vacation next week and see what
I come up with.  Please contact me directly if I forget.  Just out of
curiosity, try booting with one of your known bad configurations and
break into the the loader prompt and do the following:

set vm.old_contigmalloc=1

Scott


Tony Holmes wrote:
> I had a very interesting couple of days trying to figure out why 6.2-STABLE
> and 7.0-CURRENT, both amd64,  were giving me random hangs, panics etc.
> 
> My system:
> 
> Asus M2NPV-VM
> 4GB Ram
> 2 x Adaptec 19160 controllers
> 14 x 33GB Seagate 10k rpm scsi in a disk shelf (2 channel)
> 2 x 80GB Seagate SATA (geom mirror, system disks)
> 
> I had the system installed with 6.2 and upgraded to 7.0- (for the new nfe
> driver for the onboard NIC) and added the Adaptecs and disk. I began to play
> with geom to set them up as a RAID 10 system for a database. Same configuration
> on FreeBSD, solaris and other systems resulted in blazing fast performance.
> 
> Set up the disks, fired up a basic bonnie test and... chug chug and eventual
> random panic. Okay, maybe I messed up the geom config since I was tinkering
> around. Reboot, wait for sync to finish.... 20 hours later it was done - way
> too slow. Checked termination, cables, power, etc. All good.
> 
> Fire up bonnie... first iteration showed approx 8MBps write approx 10MBps read
> was horrendous. Decided to attempt a fresh reinstall.
> 
> Load up 6.2R amd64 cd - panic on startup just after SCSI probe delay. Tried
> once more and same thing. Okay, try 7.0 amd64.
> 
> Divide by 0 error right after SCSI probe - and that's when the thought struck
> me - 4GB ram... 
> 
> Pulled out 2GB and viola, 7.0 installed easily. Configured the Raid 10 and got
> the nice 275MBps read and 150MBps (ballpark) benchmark numbers I was expecting.
> 
> I know that amd64 supports 4gb+ (I have 2 others with SATA only that are
> running flawlessly).
> 
> So I am attempting to determine the cause of the failures.
> 
> The adaptecs are 32bit with older bios (2.57 and 3.10). They are in the 2
> 32bit pci slots of the M2NPV motherboard.
> 
> I would have thought FreeBSD would have knocked a memory hole in the 3.5-4gb
> range to accomodate the device mappings.
> 
> Does anyone have any explanations/pointers (I did search and attempt to RTFM
> with not much luck) about this?
>