Quoting r. Sean Hefty <[EMAIL PROTECTED]>: > Subject: Re: [PATCH] IB_CM: Limit the MRA timeout > > Michael S. Tsirkin wrote: > >>There's several timeout values transfered and used by the cm, most notably > >>the > >>remote cm response timeout and packet life time. Does it make more sense > >>to > >>have a single, generic timeout maximum instead? > > > > Hmm. I'm not sure - we are working around an actual broken implementation > > here - > > what do you think? > > I wasn't sure either. The MRA timeout is a combination of the packet life > time > + service timeout, which made me bring this up. The patch only handles the > service timeout portion, so we end up in the same situation if a large packet > life time is ever used.
But that comes from the SA, does it not? > >>Would it make more sense to > >>enable the maximum(s) by default, since we're dependent upon values > >>received > >>over the network? > > > > I think it would. > > So do I. > > The CM has checks to bring out of range values into range, but at the > maximum, > we get a timeout of about 2.5 hours. Multiple that by 15 retries, and the cm > can literally spend all day retrying a request. > > I was considering dropping the default maximum down to around 4-8 seconds, > which > with retries still gives us about a minute to timeout a request. The default > maximum would apply to local and remote cm timeouts, packet life time, and > service timeout, but could be overridden by the user. (Basically, with > Ishai's > patch: rename mra_timeout_limit to timeout_limit, set to a default of 20, and > replace occurrences of '31' in the code with timeout_limit.) For remote cm timeout and service timeout this makes sense - they seem currently mostly taken out of the blue on implementations I've seen. But since the packet lifetime comes from the SM, it actually has a chance to reflect some knowledge about the network topology. And since we haven't see any practical issues with packet life time yet - maybe a different paremeter for that, with a higher limit? -- MST _______________________________________________ openib-general mailing list [email protected] http://openib.org/mailman/listinfo/openib-general To unsubscribe, please visit http://openib.org/mailman/listinfo/openib-general
