[ofa-general][PATCH 1/3]mlx4: Multiple completion vectors support

[Ron Livne]

Is it possible that only one vector will be supported by the system,
yielding the function pci_enable_msix to return 1?

If so, the stack will not work properly when using only 1 vector.

Ron


On Mon, Dec 22, 2008 at 10:13 AM, Yevgeny Petrilin
<yevgenyp at mellanox.co.il> wrote:
> Roland,
>
>> We encountered a problem that when a machine didn't support the
>> required number of vectors (nvec),
>> instead of trying to get 2 vectors like in the previous version, it
>> didn't use MSI-X at all - causing a major performance degradation.
>> Maybe in a case of failure we should try lowering the number of
>> vectors to 2 (like in the previous version) or the return value of
>> pci_enable_msix and goto no_msi only in case of a second failure.
>>
>> Ron
> I agree with Ron on this issue, trying to get the number of vectors that was returned by
> pci_enable_msix seems to be the better solution in case of failure.
>
> As for the rest of the patch, I didn't find any major problems, except for a small typo:
>> +                     mdev->profile.prof[i].rx_ring_num = dev->caps.num_comp_vectors;;
> The driver worked fine with the new addition.
>
> Thanks,
> Yevgeny
>
>
>