[openib-general] scaling issues, was: uDAPL cma: add support for address and route retries, call disconnect when recving dreq

[Michael S. Tsirkin]

Quoting r. Hal Rosenstock <halr at voltaire.com>:
> Subject: Re: scaling issues, was: uDAPL cma: add support for address and route retries, call disconnect when recving dreq
> 
> On Thu, 2006-11-02 at 17:54, Michael S. Tsirkin wrote:
> > Quoting r. Arlin Davis <ardavis at ichips.intel.com>:
> > > Subject: Re: [openib-general] scaling issues, was: uDAPL cma: add support for address and route retries, call disconnect when recving dreq
> > > 
> > > Sean Hefty wrote:
> > > 
> > > >One option is having the SA (or ib_umad?) return a busy status in response to a 
> > > >MAD, but we'd still have to be able to send this response as quickly as requests 
> > > >are being received.  We could then limit the number of requests that would be 
> > > >queued in the kernel for a user.
> > > >  
> > > >
> > > 
> > > Another great option would be to have path record caching. Unfortunately 
> > > OFED 1.1 did not include ib_local_sa in the release.
> > > 
> > 
> > This won't help you much.
> > With 256 nodes all to all already gives you 65000 requests
> > which is the same order of magnitude as the reported 130000.
> 
> The requests might occur at a different time so they could be spread out
> rather than synchronized.

I don't see how caching does this.

-- 
MST