From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: <bmcfall@redhat.com> Received: from mail-ot0-f178.google.com (mail-ot0-f178.google.com [74.125.82.178]) by dpdk.org (Postfix) with ESMTP id BFC491396 for <dev@dpdk.org>; Wed, 15 Mar 2017 16:01:12 +0100 (CET) Received: by mail-ot0-f178.google.com with SMTP id i1so21351782ota.3 for <dev@dpdk.org>; Wed, 15 Mar 2017 08:01:12 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:in-reply-to:references:from:date :message-id:subject:to:cc; bh=u7KGMl84mqvbkpfUSdHswQtFuTpvmmjEaGyOQe+X6ug=; b=dqeGw8YX3lukz6mrNoRg1fwZXyV0d1wDKgYHHVzr0IPa/sh14cKaMHR9NNbyq5es/2 oWfsr7n5T2+pEI+zBIp0xjvb4JaymuAXSZpZXxFLJflTro8AnP5drH+idoyNiQ41tQDr IBJW+/R3M+iQe0u0pSbcjBLjcu6zFECUAJx0JqyMOKwap0/WPuxlCDoNcE5XOcw5cQkL xGOdA5rVyo0R/I6V2S4YFe/epo7tzzZvI5Lkru2p/UxatrJGv9w/dNieI8m4UavDU+Iw 78Dm433Fmi4ibyFdlPrOdK0WHnmZwy1Twus4hj18fFJ0dRBsV72DZHeBv20PKOTyG/0D +PTw== X-Gm-Message-State: AFeK/H01XRwoCfhb+VcENUCb/Oy5QVH7CzGqEyTnNc8Uu2Yp+2enz02GmTjHZm1DfrXCq59jaHbwwJcFjTG2z2FR X-Received: by 10.157.68.209 with SMTP id p17mr2083462otg.244.1489590072034; Wed, 15 Mar 2017 08:01:12 -0700 (PDT) MIME-Version: 1.0 Received: by 10.202.198.1 with HTTP; Wed, 15 Mar 2017 08:01:11 -0700 (PDT) In-Reply-To: <20170315112908.15b4c811@platinum> References: <20170127183800.27466-1-bmcfall@redhat.com> <20170309205119.28170-1-bmcfall@redhat.com> <20170309205119.28170-2-bmcfall@redhat.com> <20170315112908.15b4c811@platinum> From: Billy McFall <bmcfall@redhat.com> Date: Wed, 15 Mar 2017 11:01:11 -0400 Message-ID: <CAKLkqD6_T-wbZGjwy0RsxoaCyiNVAjmJwAtHftZ9rCU_RcBMZg@mail.gmail.com> To: Olivier Matz <olivier.matz@6wind.com> Cc: thomas.monjalon@6wind.com, wenzhuo.lu@intel.com, dev@dpdk.org Content-Type: text/plain; charset=UTF-8 X-Content-Filtered-By: Mailman/MimeDel 2.1.15 Subject: Re: [dpdk-dev] [PATCH v6 1/3] ethdev: new API to free consumed buffers in Tx ring X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.15 Precedence: list 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> X-List-Received-Date: Wed, 15 Mar 2017 15:01:13 -0000 On Wed, Mar 15, 2017 at 6:29 AM, Olivier Matz <olivier.matz@6wind.com> wrote: > Hi Billy, > > On Thu, 9 Mar 2017 15:51:17 -0500, Billy McFall <bmcfall@redhat.com> > wrote: > > Add a new API to force free consumed buffers on Tx ring. API will return > > the number of packets freed (0-n) or error code if feature not supported > > (-ENOTSUP) or input invalid (-ENODEV). > > > > Please double check my python coding in conf.py and make sure I > > implemented 'feature_str_len' properly. > > > > Signed-off-by: Billy McFall <bmcfall@redhat.com> > > [...] > > > diff --git a/doc/guides/prog_guide/mempool_lib.rst > b/doc/guides/prog_guide/mempool_lib.rst > > index ffdc109..a117881 100644 > > --- a/doc/guides/prog_guide/mempool_lib.rst > > +++ b/doc/guides/prog_guide/mempool_lib.rst > > @@ -132,6 +132,32 @@ These user-owned caches can be explicitly passed to > ``rte_mempool_generic_put()` > > The ``rte_mempool_default_cache()`` call returns the default internal > cache if any. > > In contrast to the default caches, user-owned caches can be used by > non-EAL threads too. > > > > +In addition to a core's local cache, many of the drivers don't release > the mbuf back to the mempool, or local cache, > > +immediately after the packet has been transmitted. > > +Instead, they leave the mbuf in their Tx ring and either perform a bulk > release when the ``tx_rs_thresh`` has been > > +crossed or free the mbuf when a slot in the Tx ring is needed. > > + > > +An application can request the driver to release used mbufs with the > ``rte_eth_tx_done_cleanup()`` API. > > +This API requests the driver to release mbufs that are no longer in > use, independent of whether or not the > > +``tx_rs_thresh`` has been crossed. > > +There are two scenarios when an application may want the mbuf released > immediately: > > + > > +* When a given packet needs to be sent to multiple destination > interfaces (either for Layer 2 flooding or Layer 3 > > + multi-cast). > > + One option is to make a copy of the packet or a copy of the header > portion that needs to be manipulated. > > + A second option is to transmit the packet and then poll the > ``rte_eth_tx_done_cleanup()`` API until the reference > > + count on the packet is decremented. > > + Then the same packet can be transmitted to the next destination > interface. > > + > > +* If an application is designed to make multiple runs, like a packet > generator, and one run has completed. > > + The application may want to reset to a clean state. > > + In this case, it may want to call the ``rte_eth_tx_done_cleanup()`` > API to request each destination interface it has > > + been using to release all of its used mbufs. > > + > > +To determine if a driver supports this API, check for the *Free Tx mbuf > on demand* feature in the *Network Interface > > +Controller Drivers* document. > > I'm not sure the mempool documentation is the proper place to document > this API. I'll suggest to move it in ethdev documentation > (poll_mode_drv.rst). > > You can keep a small paragraph in mempool lib, but keep in mind that > mempool is not necessarily a pool of mbuf (it can be any kind of object). > > Not sure this API needs to be documented in multiple places. I'll move the content to the poll_mode_drv.rst file. > > Thanks, > Olivier > > Billy