[dpdk-users] Run-to-completion or Pipe-line for QAT PMD in DPDK

Changchun Zhang changchun.zhang at oracle.com
Fri Jan 18 19:52:56 CET 2019

HI Fiona,

Changchun (Alex)

-----Original Message-----
From: Trahe, Fiona [mailto:fiona.trahe at intel.com] 
Sent: Friday, January 18, 2019 1:21 PM
To: Changchun Zhang <changchun.zhang at oracle.com>; Pathak, Pravin <pravin.pathak at intel.com>; users at dpdk.org
Cc: Trahe, Fiona <fiona.trahe at intel.com>
Subject: RE: [dpdk-users] Run-to-completion or Pipe-line for QAT PMD in DPDK

Hi Alex,

>  [changchun] Many thanks! So from this limitation, we can conclude 
> that Lcore can only dequeue the QAT queue which was enqueued by 
> itself, right. If so, then the Crypto device lib doc may be a little misleading, at least some notes should be put there.
[Fiona] Limitations are generally on the device documentation - it wouldn't make sense to pollute the lib with the limitations of individual devices. (though I understand it's easy to miss the limitations) As mentioned before, if this is an important use-case for you we would be interested in hearing about it, and we could investigate performant ways to remove the limitation.

 [changchun] Currently we don't see if it is necessary to remove this limitation or not. But we do need to confirm what the relationship between logical core, queue pair, and crypto device. As my understanding, no matter pipe line or current limitation, the QAT accepts the request from the RX queue of a queue pair and after the processing, the data will be put the TX queue on the same queue pair, it is right? Say enqueue data to the RX queue of Queue pair 1, the return data would always be put to the TX queue of Queue pair 1, not possible to other Queue pair's TX queue, right? Let me know if you did not get my question. 

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