[Scst-devel] [ofa-general] WinOF_2_0_5/SRP initiator: slow reads and eventually hangs

[Chris Worley]

On Mon, Sep 7, 2009 at 5:58 AM, Vladislav Bolkhovitin <vst at vlnb.net> wrote:
> Chris Worley, on 09/06/2009 05:41 PM wrote:
>>
>> On Sun, Sep 6, 2009 at 3:36 PM, Chris Worley<worleys at gmail.com> wrote:
>>>
>>> On Sun, Sep 6, 2009 at 3:17 PM, Bart Van Assche<bart.vanassche at gmail.com>
>>> wrote:
>>>>
>>>> On Fri, Sep 4, 2009 at 1:20 AM, Chris Worley <worleys at gmail.com> wrote:
>>>>>
>>>>> On Thu, Sep 3, 2009 at 11:38 AM, Chris Worley<worleys at gmail.com> wrote:
>>>>>>
>>>>>> I've used a couple of initiators (different systems) w/ different
>>>>>> OSes, w/ different IB cards (all QDR) and different IB stacks
>>>>>> (built-in vs. OFED) and can repeat the problem in all but the
>>>>>> RHEL5.2/OFED 1.4.1 target and initiator (but, if the initiator is
>>>>>> WinOF and the target is RHEL5.2/OFED1.4.1, then the problem does
>>>>>> repeat).
>>>>>
>>>>> Here's a twist: I used the Ubuntu initiator w/ one of the RHEL
>>>>> targets, and the RHEL initiator (same machine as was running WinOF
>>>>> from the beginning of this thread) w/ one of the Ubuntu targets: in
>>>>> both cases, the problem does not repeat.
>>>>>
>>>>> That makes it sound like OFED is the cure on either side of the
>>>>> connection, but does not explain the issue w/ WinOF (which does fail
>>>>> w/ either Ununtu or RHEL targets).
>>>>
>>>> These results are strange. Regarding the Linux-only tests, I was
>>>> assuming failure of a single component (Ubuntu SRP initiator, OFED SRP
>>>> initiator, Ubuntu IB driver, OFED IB driver or SRP target), but for
>>>> each of these components there is at least one test that passes and at
>>>> least one test that fails. So either my assumption is wrong or one of
>>>> the above test results is not repeatable. Do you have the time to
>>>> repeat the Linux-only tests ?
>>>
>>> Last night I was rerunning the RHEL5.2 initiator w/ Ubuntu client, and
>>> the problem repeated; now, I can't repeat the case where it didn't
>>> fail.  Still, no errors, other than the eventual timeouts previously
>>> shown; the target thinks all is fine, the initiator is stuck.
>>
>> ... and I haven't had any success w/ Ubuntu target and initiator, 8.10 or
>> 9.04.
>
> 1. Try with kernel parameter maxcpus=1. It will somehow relax possible races
> you have, although not completely.

I finally got around to this test... 1 CPU works very well, w/o hangs
(will test all night to see if this holds true), 2 or more don't.
This is dual-socket NHM, so I can't specify more than one processor
w/o getting more than one socket.

Chris
>
> 2. Try with another hardware, including motherboard. You can have something
> like http://lkml.org/lkml/2007/7/31/558 (not exactly it, of course)
>
>> Chris
>>>
>>> Chris
>>>>
>>>> Bart.
>>>>
>
>