From mboxrd@z Thu Jan  1 00:00:00 1970
From: Jerin Jacob <jerin.jacob@caviumnetworks.com>
Subject: Re: [PATCH v4 1/6] eventdev: introduce event driven
 programming model
Date: Mon, 30 Jan 2017 16:12:25 +0530
Message-ID: <20170130104224.GA28638@localhost.localdomain>
References: <1480996340-29871-1-git-send-email-jerin.jacob@caviumnetworks.com>
 <1482312326-2589-1-git-send-email-jerin.jacob@caviumnetworks.com>
 <1482312326-2589-2-git-send-email-jerin.jacob@caviumnetworks.com>
 <9184057F7FC11744A2107296B6B8EB1E01E5EF2C@FMSMSX108.amr.corp.intel.com>
 <59AF69C657FD0841A61C55336867B5B035B8EBB9@IRSMSX103.ger.corp.intel.com>
 <9184057F7FC11744A2107296B6B8EB1E01E5F0AC@FMSMSX108.amr.corp.intel.com>
 <9184057F7FC11744A2107296B6B8EB1E01E5F3D3@FMSMSX108.amr.corp.intel.com>
 <20170126093924.GA5276@localhost.localdomain>
 <9184057F7FC11744A2107296B6B8EB1E01E5F76C@FMSMSX108.amr.corp.intel.com>
Mime-Version: 1.0
Content-Type: text/plain; charset="us-ascii"
Cc: "Richardson, Bruce" <bruce.richardson@intel.com>, "'dev@dpdk.org'"
 <dev@dpdk.org>, "'thomas.monjalon@6wind.com'" <thomas.monjalon@6wind.com>,
 "'hemant.agrawal@nxp.com'" <hemant.agrawal@nxp.com>, "Van Haaren, Harry"
 <harry.van.haaren@intel.com>, "McDaniel, Timothy"
 <timothy.mcdaniel@intel.com>
To: "Eads, Gage" <gage.eads@intel.com>
Return-path: <dev-bounces@dpdk.org>
Received: from NAM02-CY1-obe.outbound.protection.outlook.com
 (mail-cys01nam02on0071.outbound.protection.outlook.com [104.47.37.71])
 by dpdk.org (Postfix) with ESMTP id 20DA93237
 for <dev@dpdk.org>; Mon, 30 Jan 2017 11:42:42 +0100 (CET)
Content-Disposition: inline
In-Reply-To: <9184057F7FC11744A2107296B6B8EB1E01E5F76C@FMSMSX108.amr.corp.intel.com>
List-Id: DPDK patches and discussions <dev.dpdk.org>
List-Unsubscribe: <http://dpdk.org/ml/options/dev>,
 <mailto:dev-request@dpdk.org?subject=unsubscribe>
List-Archive: <http://dpdk.org/ml/archives/dev/>
List-Post: <mailto:dev@dpdk.org>
List-Help: <mailto:dev-request@dpdk.org?subject=help>
List-Subscribe: <http://dpdk.org/ml/listinfo/dev>,
 <mailto:dev-request@dpdk.org?subject=subscribe>
Errors-To: dev-bounces@dpdk.org
Sender: "dev" <dev-bounces@dpdk.org>

On Thu, Jan 26, 2017 at 08:39:57PM +0000, Eads, Gage wrote:
> 
> 
> >  -----Original Message-----
> >  From: Jerin Jacob [mailto:jerin.jacob@caviumnetworks.com]
> >  Sent: Thursday, January 26, 2017 3:39 AM
> >  To: Eads, Gage <gage.eads@intel.com>
> >  Cc: Richardson, Bruce <bruce.richardson@intel.com>; 'dev@dpdk.org'
> >  <dev@dpdk.org>; 'thomas.monjalon@6wind.com'
> >  <thomas.monjalon@6wind.com>; 'hemant.agrawal@nxp.com'
> >  <hemant.agrawal@nxp.com>; Van Haaren, Harry
> >  <harry.van.haaren@intel.com>; McDaniel, Timothy
> >  <timothy.mcdaniel@intel.com>
> >  Subject: Re: [dpdk-dev] [PATCH v4 1/6] eventdev: introduce event driven
> >  programming model
> >  
> >  Considering different implementation has different behaviors, How about
> >  enumerating the overflow policy at the port configuration time? and let
> >  implementation act accordingly to avoid fast-patch change in
> >  application(effects in all implementation irrespective of the capability)
> >  
> >  possible enumerating value at the port configuration time,
> >  - PANIC or similar scheme to denote it cannot proceed
> >  - TAIL DROP
> >  or any expected application behavior you want to add
> 
> I wonder if that's necessary? Hardware behavior a) means the function will always return nb_events. If hardware drops the event(s), I assume enqueue_burst would still return nb_events and the app behaves as if all events were sent. If the enqueue fails (ret < nb_events), app software could check rte_errno and take the action it deems necessary. So all fast-path enqueue code could look like:
> 
> ret = rte_event_enqueue_burst(..., nb_events);
> if (ret < nb_events) {

I was concerned about this section of the application code get bloated with
drivers specific actions. But, If we want the actions based on per event then
I think, it makes sense to update the specification with new rte_errno values
for enqueue.

>     ....
> }