svn commit: r203889 - in stable/8/sys: cam cam/ata cam/scsi dev/ahci dev/asr dev/ata dev/ciss dev/hptiop dev/hptrr dev/mly dev/mpt dev/ppbus dev/siis dev/trm dev/twa dev/usb/storage

Lawrence Stewart lstewart at
Fri Feb 19 13:56:21 UTC 2010

On 02/19/10 19:50, Alexander Motin wrote:
> Lawrence Stewart wrote:
>> On 02/19/10 02:53, Matthew Jacob wrote:
>>> Just a total swag here, but reduce the openings via camcontrol to<  32,
>>> or even<  16
>> Thanks for the suggestion. camcontrol doesn't seem able to futz with the
>> mpt controller e.g.:
>> root at server# camcontrol identify da0 -v
>> (pass0:mpt0:0:2:0): ATAPI_IDENTIFY. ACB: a1 00 00 00 00 40 00 00 00 00
>> 00 00
>> (pass0:mpt0:0:2:0): CAM status: CCB request was invalid
> IDENTIFY is an ATA command. It is not working there now, as mpt on some
> level translates ATA into SCSI. `camcontrol inquiry da0` and the others
> probably should work.

root at server# camcontrol inquiry da0
pass0: <LSILOGIC Logical Volume 3000> Fixed Direct Access SCSI-2 device
pass0: 300.000MB/s transfers, Command Queueing Enabled

>> However, there does appear to be a relevant sysctl:
>> root at server# sysctl dev.mpt.0
>> dev.mpt.0.%desc: LSILogic SAS/SATA Adapter
>> dev.mpt.0.%driver: mpt
>> dev.mpt.0.%location: slot=3 function=0
>> dev.mpt.0.%pnpinfo: vendor=0x1000 device=0x0050 subvendor=0x1000
>> subdevice=0x3060 class=0x010000
>> dev.mpt.0.%parent: pci2
>> dev.mpt.0.debug: 3
>> dev.mpt.0.role: 1
>> dev.mpt.0.vol_member_wce: NC
>> dev.mpt.0.vol_queue_depth: 128
>> dev.mpt.0.vol_resync_rate: 0
>> dev.mpt.0.nonoptimal_volumes: 0
>> Setting dev.mpt.0.vol_queue_depth=32, I can still trigger the
>> "mpt0: mpt_cam_event: 0x16" messages by doing an svn up on the src tree.
>> Same if I set depth to 16, so unfortunately it doesn't seem to do help
>> in this case.
> I am not sure what this sysctl does, but it is mpt driver own sysctl. It
> has nothing common with number of tags used by CAM (at least directly).

Ah ok, I misunderstood what openings meant in this context... I thought 
it was the queue depth.

So if I restore dev.mpt.0.vol_queue_depth=128 and do the following:

root at server# camcontrol tags da0
(pass0:mpt0:0:2:0): device openings: 255

root at server# camcontrol tags da0 -N 64
(pass0:mpt0:0:2:0): tagged openings now 64
(pass0:mpt0:0:2:0): device openings: 64

I can still trigger the "mpt0: mpt_cam_event: 0x16" messages. Same with 
openings set to 32.

If I lower the openings down to 16, I still get fairly large stalls in 
disk IO, but the mpt_cam_event messages no longer appear. Hmmmm...


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