[ofa-general] SRP/mlx4 interrupts throttling performance

[Vu Pham]

Vladislav Bolkhovitin wrote:
> Cameron Harr wrote:
>>>>>> Vladislav Bolkhovitin wrote:
>>>>>>> I guess, you use a regular caching IO? The lowest packet size it 
>>>>>>> can produce is a PAGE_SIZE (4K). Target can't change it. You can 
>>>>>>> have lower packets only with O_DIRECT or sg interface. But I'm 
>>>>>>> not sure it will be performance effective.
>>>>>> I do everything with Direct IO, which is automatic when using the 
>>>>>> BLOCKIO method in SCST.
>>>>> I meant on initiator(s), not on the target.
>>>>>
>>>> Sorry - but yes, I always run the benchmark apps with direct IO
>>> Then, there's one more reason why we should find out the cause of 
>>> such a big variation between runs. Can you repeat all the tests with 
>>> the latest SCST SVN trunk/ including SRPT driver with each run for 
>>> at least few minutes?
>>
>>  From a little testing, the updated SCST tree doesn't work with the 
>> OFED-1.3.1 SRP stack, though I have gotten it working with the 
>> infiniband drivers in the normal distribution kernel. Shall I use 
>> those modules?
>
> I think, only Vu can answer it.

ofed-1.3.1 srpt only works with scst-1.0.0
You can run 2.6.26 + its IB stack + latest SVN scst and srpt

-vu

>
>> Also, as I mentioned before, my time is going to be fairly limited 
>> for a while, but I'll try to squeeze this in and will make sure I run 
>> for longer periods of time. I'll also try to calculate an exact end 
>> number based on iop/runtime.
>>> Which backstorage do you use for BLOCKIO?
>> Fusion IO ioDrive. I generally use 1 or 2, but somtimes up to 4 at a 
>> time.
>
> It might be a reason of not stable results. Can you try with NULLIO to 
> narrow things down a bit?