[ofa-general] SRP/mlx4 interrupts throttling performance

[Vladislav Bolkhovitin]

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.

> 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?