From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from dpdk.org (dpdk.org [92.243.14.124]) by dpdk.space (Postfix) with ESMTP id 86CAEA0096 for ; Wed, 8 May 2019 16:01:07 +0200 (CEST) Received: from [92.243.14.124] (localhost [127.0.0.1]) by dpdk.org (Postfix) with ESMTP id 1BF4137AF; Wed, 8 May 2019 16:01:07 +0200 (CEST) Received: from mga14.intel.com (mga14.intel.com [192.55.52.115]) by dpdk.org (Postfix) with ESMTP id A94EF2BD5; Wed, 8 May 2019 16:01:01 +0200 (CEST) X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga006.jf.intel.com ([10.7.209.51]) by fmsmga103.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 08 May 2019 07:01:00 -0700 X-ExtLoop1: 1 Received: from irsmsx109.ger.corp.intel.com ([163.33.3.23]) by orsmga006.jf.intel.com with ESMTP; 08 May 2019 07:00:58 -0700 Received: from irsmsx101.ger.corp.intel.com ([169.254.1.115]) by IRSMSX109.ger.corp.intel.com ([169.254.13.189]) with mapi id 14.03.0415.000; Wed, 8 May 2019 15:00:57 +0100 From: "Trahe, Fiona" To: Shally Verma , "dev@dpdk.org" CC: "akhil.goyal@nxp.com" , Ashish Gupta , "Daly, Lee" , Sunila Sahu , "stable@dpdk.org" , "Trahe, Fiona" Thread-Topic: [PATCH v2] doc/compress: clarify error handling on data-plane Thread-Index: AQHU7uRoniPOIsNkTEyu55+FfYvFQqZB0WaAgBMsX4CACwRwAIAAF5KggAEuXICAACaHkA== Date: Wed, 8 May 2019 14:00:56 +0000 Message-ID: <348A99DA5F5B7549AA880327E580B4358975602D@IRSMSX101.ger.corp.intel.com> References: <1554740072-11898-1-git-send-email-fiona.trahe@intel.com> <1554821747-27868-1-git-send-email-fiona.trahe@intel.com> <348A99DA5F5B7549AA880327E580B4358974F5BC@IRSMSX101.ger.corp.intel.com> <348A99DA5F5B7549AA880327E580B435897553D3@IRSMSX101.ger.corp.intel.com> In-Reply-To: Accept-Language: en-IE, en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-titus-metadata-40: eyJDYXRlZ29yeUxhYmVscyI6IiIsIk1ldGFkYXRhIjp7Im5zIjoiaHR0cDpcL1wvd3d3LnRpdHVzLmNvbVwvbnNcL0ludGVsMyIsImlkIjoiNjc2YTllYjctODY1Ny00ZDhmLWE5OWYtMTk1ZGJlYWU5ODMxIiwicHJvcHMiOlt7Im4iOiJDVFBDbGFzc2lmaWNhdGlvbiIsInZhbHMiOlt7InZhbHVlIjoiQ1RQX05UIn1dfV19LCJTdWJqZWN0TGFiZWxzIjpbXSwiVE1DVmVyc2lvbiI6IjE3LjEwLjE4MDQuNDkiLCJUcnVzdGVkTGFiZWxIYXNoIjoiUXJRV2F3eWYzYjFIZWlxQ2FjSFBtTU95a3VXUFBjOGpOc2tmdTNVZUViQlBKYkZMeVNWNnh2ZnBpVmlnNEFhbSJ9 x-ctpclassification: CTP_NT dlp-product: dlpe-windows dlp-version: 11.0.600.7 dlp-reaction: no-action x-originating-ip: [163.33.239.180] Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Subject: Re: [dpdk-stable] [PATCH v2] doc/compress: clarify error handling on data-plane X-BeenThere: stable@dpdk.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: patches for DPDK stable branches List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: stable-bounces@dpdk.org Sender: "stable" HI Shally, > -----Original Message----- > From: Shally Verma [mailto:shallyv@marvell.com] > Sent: Wednesday, May 8, 2019 1:41 PM > To: Trahe, Fiona ; dev@dpdk.org > Cc: akhil.goyal@nxp.com; Ashish Gupta ; Daly, Lee ; Sunila > Sahu ; stable@dpdk.org > Subject: RE: [PATCH v2] doc/compress: clarify error handling on data-plan= e >=20 > Hi Fiona >=20 >=20 > > -----Original Message----- > > From: Trahe, Fiona > > Sent: Tuesday, May 7, 2019 11:54 PM > > To: Shally Verma ; dev@dpdk.org > > Cc: akhil.goyal@nxp.com; Ashish Gupta ; Daly, Lee > > ; Sunila Sahu ; stable@dpdk.org; > > Trahe, Fiona > > Subject: RE: [PATCH v2] doc/compress: clarify error handling on data-pl= ane > > > > Hi Shally > > > > > > > > + > > > > > > +There are some exceptions whereby errors can occur on the > > > > ``enqueue``. > > > > > > +For any error which can occur in a production environment and > > > > > > +can be successful after a retry with the same op the PMD may > > > > > > +return the error on the enqueue. > > > > > This statement looks bit confusing. > > > > > Seems like we are trying to add a description regarding op status > > > > > check even after the enqueue call unlike current scenario, where > > > > > app only check for it after dequeue? > > > > [Fiona] The line following this explains that there is no need to > > > > check op.status in this case. > > > > Maybe it's not obvious that the application SHOULD check that all > > > > ops are enqueued? > > > > I can reword as: > > > > The application should always check the value returned by the enque= ue. > > > > If less than the full burst is enqueued there's no need for the > > > > application to check op.status of any or every op - it can simply > > > > retry from the return > > > > value+1 in a later enqueue and expect success. > > > > > > > I agree to purpose of patch but have these confusions when I read > > description above: > > > > > > My understand is , if op status is INVALID_ARGS or any ERROR which is > > > permanent in nature, Then nb_enqd return will be less than actually > > passed. > > [Fiona] True. > > > > > Regardless of whatever reason, if any time app gets nb_enqd < actuall= y > > > passed, then app should check status of nb_enqd + 1th op > > [Fiona]. No, that's exactly what I was proposing to avoid. > > > > > to find exact cause of failure and then either attempt re-enqueue Or > > > correct op preparation or take any other appropriate action. > > [Fiona] I was proposing to constrain PMDs to only return a subset of er= rors > > on the enqueue, so apps could be optimised. > > But if you think it's not possible for PMDs to comply with it, then yes= , apps > > would always have to check status of nb_enqd + 1th op, and fork dependi= ng > > on the status. > > Is this the case? > > If so, much of this patch is unnecessary and I'll send a simplified v3 = as almost > > any status can be returned anywhere. > > > [Shally] Okay. I seem to understand it now. > Purpose seem reasonable just a simpler rephrase would help. > It will be easier for me to further feedback on 1st v2 patch sent. So wil= l send it another email. [Fiona] ok, will look for that. =20 > > > Also, STATUS_ERROR is very generic, it can be when queue is full in > > > which case app can re-attempt an enqueue of same op > > OR > > > It can also indicate any irrecoverable error on enqueue, in which app > > > just probably has to reset everything. For such kind of case, it migh= t > > > not be possible for PMD design to even push it into completion queue > > > for an app to dequeue . I would suggest add another status code typ= e > > > which reflect permanent error condition i.e. irrecoverable error code > > > which tells an app to perform PMD qp reset/re-init to recover and sim= plify > > description just to state an expected APP behavior to avoid infinite lo= op > > condition. > > > It is then an app choice whether or not to check for op status for > > > error after enqueue depending on whether its running in production > > environment or dev environment. > > [Fiona] I wouldn't expect ERROR in a queue full case. I'd see ERROR as = the > > catch-all when some other specific status isn't appropriate. If you thi= nk > > there's a need for another specific status then best send an API patch > > proposing it. This patch is only documenting the existing set. >=20 > [Shally] Sorry, I missed. STATUS_NOT_PROCESSED can be indication of queue= _full. > STATUS_ERROR on dequeue =3D any catch-all error case > STATUS_ERROR on enqueue =3D any irrecoverable error on op. app should not= attempt same op or may be > reset queue pair or PMD. >=20 > Is this interpretation correct? [Fiona] Yes