[openib-general][PATCH] srp: tuned parameters,

[Vu Pham]

Roland Dreier wrote:
> I finally looked this over.
> 
> First, this should be two patches: making srp_sg_tablesize tunable
> should be a separate change from making it possible to specify
> max_cmd_per_lun for a target.
> 

OK, I'll break it to two patches

> The srp_sg_tablesize change makes the default number of SG entries
> quite a bit larger than it is now, which makes the default max IU
> length much bigger.  Is this justified?  What workload creates such
> huge SG lists?


With semi-realistic benchmark xdd, orion I'm seeing better 
number with this default value
I think that we can reduce the default value for 
srp_sg_tablesize and up to users to bump it up by overriding 
  when loading up the module.

> 
> For the cmd_per_lun change, shouldn't the line
> 
> 
>>+			target->scsi_host->cmd_per_lun = token;
> 
> 
> be something like
> 
> 			target->scsi_host->cmd_per_lun = min(token, SRP_SQ_SIZE);
> 
> otherwise it's too easy to overflow a send queue by mistake.
> 

Yes. I'll fix it

Vu