[openib-general] QoS configuration using opensm

[Hal Rosenstock]

Hi Adit,

On Tue, 2006-12-12 at 13:45, Adit Ranadive wrote:
> Hi,
> 
> Im trying to establish some QoS parameters for allowing apps to
> communicate using different service levels.
> 
> Curently my opensm.opts looks like this:
> 
> # QoS default options
> qos_max_vls 15
> qos_high_limit 0
> qos_vlarb_high 0:4,1:0,2:0,3:0,4:0,5:0,6:0,7:255,8:0,9:0,10:0,11:0,12:0,13:0,14:0
> qos_vlarb_low 0:4,1:100,2:100,3:100,4:100,5:100,6:100,7:100,8:100,9:100,10:100,11:100,12:100,13:4,14:4
> qos_sl2vl 7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7
> 
> # QoS CA options
> qos_ca_max_vls 15
> qos_ca_high_limit 0
> qos_ca_vlarb_high
> 0:4,1:0,2:0,3:0,4:0,5:0,6:0,7:0,8:0,9:0,10:0,11:0,12:0,13:0,14:0
> qos_ca_vlarb_low
> 0:4,1:4,2:4,3:4,4:4,5:4,6:4,7:4,8:4,9:4,10:4,11:4,12:4,13:4,14:4
> qos_ca_sl2vl 0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,7
> 
> Im not sure which options to modify QoS default or QoS CA?

Depends what you want to do.

The defaults are used by all unless overridden by the specific
configuration by target port type (ca, rtr, sw0, ext).

> Should both tables have same values?

They can but if they do, you don't need one of them (likely the ca_
one).

> My setup includes no switch and back two machines connected to each
> other using the IB cable.
> 
> Since im mapping service level 7 to all VLs

No, it's the other way around: You are mapping all SLs to VL 7.

> all apps using sl=7 should receive equal bandwidth?

These tables only deal with arbitration amongst the VLs (and the mapping
of the SLs to VLs). They do not deal with fairness amongst applications
sharing the same SL.

> Also since in VLarb_high table weight of SL=7 is 255?

That setting means that the high priority limit can be unbounded and low
priority will only be scheduled if there is no high priority work to do.

-- Hal

> Thanks,
> Regards,
> Adit
> 
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