[ofa-general] Re: [PATCH] opensm/opensm/osm_subnet.c: add checks for HOQ and Leaf HOQ input values

[Hal Rosenstock]

On Wed, 2008-04-09 at 08:38 -0700, weiny2 at llnl.gov wrote:
> > On Wed, 2008-04-09 at 10:01 +0000, Sasha Khapyorsky wrote:
> >> Hi Ira,
> >>
> >> On 16:48 Tue 08 Apr     , weiny2 at llnl.gov wrote:
> >> > As per Hal's comments change the alternate value for [leaf] HOQ to be
> >> > "infinity" when the user specifies a value larger than "infinity".
> >>
> >> Actually I would prefer original version of the patch. The main reason
> >> is that infinite packet life time is really dangerous thing - in case
> >> when a fabric is routed with credit loops (very common case with default
> >> min-hops routing) it leads to total fabric stuck and not just to some
> >> performance degradation.
> >>
> >> So I think it is safer to reject invalid value and to set the default
> >> (log an error, etc.i). As it was done in the original version of the
> >> patch.
> >>
> >> Hal, do you agree?
> >
> > Safer yes but I think it is less to the intent of the admin who just
> > doesn't understand the max value for this and that's why I proposed this
> > change. My preference is to max it out but it comes down to a judgment
> > call. There's a downside either way.
> 
> What if we set it to 0x13?  This would be the maximum value that will not
> "lock" up the fabric.  We could also add to the error message that the
> admin needs to specify 0x14 if they specifically want "infinity" to be
> set?

So disallow the setting to infinity ?

-- Hal

> Ira
> 
> 
>