Subject: RE: [rddp] verb spec clarification

From: "Culley, Paul" <[email-masked]>
Date: Tue, 29 Mar 2005 07:41:49 -0600

For Verbs, The answer is no.

Section 7.6.3 pg 112 near top
"If the length of the access is zero, the RI MUST NOT perform any of the
above checks on the Memory Region."

Section 7.10.6.2 pg 124, 2/3 down
"If the length of the access is zero, the RI MUST NOT perform any of the
above checks on the Memory Window."

Paul R. Culley
HP Fellow
281-514-5543

> -----Original Message-----
> From: [email-masked] [mailto:[email-masked]] On 
> Behalf Of Patricio Kaplan
> Sent: Monday, March 28, 2005 1:07 PM
> To: [email-masked]
> Subject: [rddp] verb spec clarification
> 
> Section 9.2.5.1 states that QPs have Inbound RDMA Read enable 
> and Inbound RDMA Write and inbound RDMA Read Response enable.
>  
> Does the  inbound RDMA Read Response enable check apply to a 
> zero length read response?
> 
> Thanks,
> -Patricio
> 
> _______________________________________________
> rddp mailing list
> [email-masked]
> https://www1.ietf.org/mailman/listinfo/rddp
> 

_______________________________________________
rddp mailing list
[email-masked]
https://www1.ietf.org/mailman/listinfo/rddp

---

From: Caitlin Bestler <[email-masked]>
Date: Tue, 29 Mar 2005 06:38:34 -0800

> above checks on the Memory Window."

Putting aside any overly broad use of the phrase "above checks",
would you agree that the *only* thing special about zero length
reads is that the STag is not validated?

Specifically, the RDMA Read Response will still be ordered just
as the response to any other RDMA Read Request, correct?

Therefore, it will consume a resource (on either a connection
or wider scale). That resource SHOULD/MUST be properly accounted
for by *some* mechanism.

I can think of nothing in the wire specifications that would
justify suppressing of normal resource checking for zero length
reads. The wire protocol does not specify *how* the local
interface tracks resources, but the security draft requires
that they be managed somehow whenever they are used across
multiple connections or are in any way a resource more
limited than just host memory.

---

From: Caitlin Bestler <[email-masked]>
Date: Tue, 29 Mar 2005 07:41:00 -0800

> above checks on the Memory Window."

Additional point: checking IRD credits is a check on the connection(QP)
not on the Memory Region/Memory Window.