From mboxrd@z Thu Jan  1 00:00:00 1970
From: Jerin Jacob <jerin.jacob@caviumnetworks.com>
Subject: Re: [PATCH v2 3/5] test: add distributor_perf autotest
Date: Wed, 4 Jan 2017 18:39:54 +0530
Message-ID: <20170104130952.GC19798@localhost.localdomain>
References: <1480567821-70846-2-git-send-email-david.hunt@intel.com>
 <1482381428-148094-1-git-send-email-david.hunt@intel.com>
 <1482381428-148094-4-git-send-email-david.hunt@intel.com>
 <20161222121943.GA8778@localhost.localdomain>
 <088a8953-9c8f-0665-7a53-505cd1c389bc@intel.com>
Mime-Version: 1.0
Content-Type: text/plain; charset="us-ascii"
Cc: <dev@dpdk.org>, <bruce.richardson@intel.com>
To: "Hunt, David" <david.hunt@intel.com>
Return-path: <dev-bounces@dpdk.org>
Received: from NAM02-BL2-obe.outbound.protection.outlook.com
 (mail-bl2nam02on0069.outbound.protection.outlook.com [104.47.38.69])
 by dpdk.org (Postfix) with ESMTP id 25B041094
 for <dev@dpdk.org>; Wed,  4 Jan 2017 14:10:16 +0100 (CET)
Content-Disposition: inline
In-Reply-To: <088a8953-9c8f-0665-7a53-505cd1c389bc@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 Mon, Jan 02, 2017 at 04:24:01PM +0000, Hunt, David wrote:
> 
> 
> On 22/12/2016 12:19 PM, Jerin Jacob wrote:
> > On Thu, Dec 22, 2016 at 04:37:06AM +0000, David Hunt wrote:
> > > +	struct rte_distributor_burst *d = arg;
> > > +	unsigned int count = 0;
> > > +	unsigned int num = 0;
> > > +	unsigned int id = __sync_fetch_and_add(&worker_idx, 1);
> > Use rte_atomic equivalent
> 
> Jerin,
>     I'm looking for an equivalent, but I can't seem to find one. Here I'm
> assigning 'id' with the incremented value of worker_idx in one statement.
> However, rte_atomic32_add just increments the variable and returns void, so
> I'd have to use two statements, losing the atomicity.
> 
>   static inline void
>   rte_atomic32_add(rte_atomic32_t *v, int32_t inc)

It would have been better rte_atomic32_add returns the old value.

> 
> There's a second reason why I can't use the rte_atomics, and that's because
> worker_idx is a volatile.

may be you could change worker_idx as rte_atomic32_t

> 
> Maybe we could add new atomic functions in the future to address this?

Yes. I guess, the fixing the return value of  rte_atomic*_[add/sub] may
be enough

> 
> Thanks,
> Dave.