[openib-general] is wc valid if ib_poll_cq() returns zero

[somenath]

Sean Hefty wrote:

> somenath wrote:
>
>> just to make sure I conveyed the exact thing I meant, if I change
>> the above code as follows:
>>
>> while (ib_poll_cq(cq, 1, &wc) > 0) {
>>      process completion();
>> }
>> rearm CQ;
>>
>> then I just get notification once, and don't get any futher
>> notifications...so I assume rearm CQ should be done even if
>> ib_poll_cq() returns zero.
>
>
> Hmm... what HCA cards and svn version are you using?  Mellanox cards 
> generate new events if any completions remain on the CQ.  So, if 
> ib_poll_cq() isn't finding any completions, then another event should 
> be generated.  If ib_poll_cq() is returning a completion, then it 
> sounds like there's a bug with ib_poll_cq() returning the wrong number 
> of completions.
>
> - Sean


hardware config: PCI express machine with PCI-Express cards of Mellanox 
HCA.

Exact same configuration was working with gen1 stack (no change in the 
hardware setup).
you can find rest of the details here:
===================================================
[root at alekhine bin]# ./ibstat
CA 'mthca0'
        CA type: MT25208 (MT23108 compat mode)
        Number of ports: 2
        Firmware version: 4.6.0
        Hardware version: a0
        Node GUID: 0x0005ad0000039abc
        System image GUID: 0x0005ad000100d050
        Port 1:
                State: Active
                Physical state: LinkUp
                Rate: 10
                Base lid: 114
                LMC: 0
                SM lid: 1
                Capability mask: 0x00510a68
                Port GUID: 0x0005ad0000039abd
        Port 2:
                State: Down
                Physical state: Polling
                Rate: 10
                Base lid: 0
                LMC: 0
                SM lid: 0
                Capability mask: 0x00510a68
                Port GUID: 0x0005ad0000039abe
=========================================================

I am using the version of gen2 code as distributed in RH version 4 update 3
since I am trying to get a port on this version of the distribution.
(so don't know the exact svn version they pulled from, I just use the RPM's
in their binary distribution).

thanks, som.