From mboxrd@z Thu Jan  1 00:00:00 1970
From: Thomas Monjalon <thomas.monjalon@6wind.com>
Subject: Re: [PATCH v3] eal: restrict cores detection
Date: Fri, 16 Sep 2016 16:04:06 +0200
Message-ID: <10166504.1OkXfxRTa7@xps13>
References: <1453661393-85704-1-git-send-email-jianfeng.tan@intel.com>
 <1472693507-11369-1-git-send-email-jianfeng.tan@intel.com>
 <20160902165310.GA20356@bricha3-MOBL3>
Mime-Version: 1.0
Content-Type: text/plain; charset="us-ascii"
Content-Transfer-Encoding: 7Bit
Cc: dev@dpdk.org, david.marchand@6wind.com, pmatilai@redhat.com,
 stephen@networkplumber.org
To: Bruce Richardson <bruce.richardson@intel.com>,
 Jianfeng Tan <jianfeng.tan@intel.com>
Return-path: <dev-bounces@dpdk.org>
Received: from mail-wm0-f53.google.com (mail-wm0-f53.google.com [74.125.82.53])
 by dpdk.org (Postfix) with ESMTP id B911568D9
 for <dev@dpdk.org>; Fri, 16 Sep 2016 16:04:08 +0200 (CEST)
Received: by mail-wm0-f53.google.com with SMTP id k186so43584668wmd.0
 for <dev@dpdk.org>; Fri, 16 Sep 2016 07:04:08 -0700 (PDT)
In-Reply-To: <20160902165310.GA20356@bricha3-MOBL3>
List-Id: patches and discussions about DPDK <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>

2016-09-02 17:53, Bruce Richardson:
> On Thu, Sep 01, 2016 at 01:31:47AM +0000, Jianfeng Tan wrote:

It would help the discussion to have a problem statement here.

> > This patch uses pthread_getaffinity_np() to narrow down detected
> > cores before parsing coremask (-c), corelist (-l), and coremap
> > (--lcores).
> > 
> > The purpose of this patch is to leave out these core related options
> > when DPDK applications are deployed under container env, so that
> > users only specify core restriction as starting the instance.
> > 
> > Note: previously, some users are using isolated CPUs, which could
> > be excluded by default. Please add commands like taskset to use
> > those cores.
> > 
> > Test example:
> > $ taskset 0xc0000 ./examples/helloworld/build/helloworld -m 1024
> > 
> 
> So, to be clear, does this patch mean that DPDK cannot use isolated cores
> any more unless you explicitly run the app using taskset?
> Is so, NAK, since isolating cores has been part of standard DPDK setup since
> the first versions, and I don't believe that we should break that behaviour.

So how could we help the container use-case?
Any suggestions?