RE: iSCSI: freeing resources during data-in and r2t

To: "Mallikarjun C. (E-mail)" <cbm@rose.hp.com>

Subject: RE: iSCSI: freeing resources during data-in and r2t

From: Eddy Quicksall <eddy_quicksall@ivivity.com>

Date: Wed, 17 Jul 2002 12:14:32 -0400

Cc: "ips@ece. cmu. edu (E-mail)" <ips@ece.cmu.edu>

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I think see a slight inefficiency in how resources are freed when multiple data-in and r2t's PDU's are used when ErrorRecoverLevel > 0 or TCP ACK is not available to the iSCSI layer.

Data-in and R2T's use DataSN and R2TSN. To free those resources, ExpStatSN is used.

But if several R2T's and/or Data-in PDU's were used, resources used for those PDU's are tied up for the entire command.

Since other commands could be received during this time, it would be nice if those commands could contain information that would tell the target that the R2T and/or Data-in PDU's have been received.

I know a radical change at this point is probably a bad idea but I just wanted to throw out the idea ... if the StatSN/ExpStatSN were changed to something like RespSN/ExpRespSN and if everything going from the target to the initiator carried a new RespSN, then the resources could be freed up sooner.

I would hate to use the A bit for this because it causes more traffic.

Eddy

mailto:Eddy_Quicksall@iVivity.com