From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mga01.intel.com (mga01.intel.com [192.55.52.88]) by dpdk.org (Postfix) with ESMTP id 0B06B5F51; Thu, 25 Oct 2018 18:47:12 +0200 (CEST) X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga005.jf.intel.com ([10.7.209.41]) by fmsmga101.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 25 Oct 2018 09:47:12 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.54,424,1534834800"; d="scan'208";a="268768249" Received: from fmsmsx106.amr.corp.intel.com ([10.18.124.204]) by orsmga005.jf.intel.com with ESMTP; 25 Oct 2018 09:47:11 -0700 Received: from fmsmsx123.amr.corp.intel.com (10.18.125.38) by FMSMSX106.amr.corp.intel.com (10.18.124.204) with Microsoft SMTP Server (TLS) id 14.3.319.2; Thu, 25 Oct 2018 09:47:11 -0700 Received: from shsmsx101.ccr.corp.intel.com (10.239.4.153) by fmsmsx123.amr.corp.intel.com (10.18.125.38) with Microsoft SMTP Server (TLS) id 14.3.319.2; Thu, 25 Oct 2018 09:47:10 -0700 Received: from shsmsx103.ccr.corp.intel.com ([169.254.4.161]) by SHSMSX101.ccr.corp.intel.com ([169.254.1.102]) with mapi id 14.03.0415.000; Fri, 26 Oct 2018 00:47:09 +0800 From: "Zhang, Qi Z" To: "Xing, Beilei" CC: "dev@dpdk.org" , "stable@dpdk.org" Thread-Topic: [PATCH] net/i40e: fix Rx instability with vector mode Thread-Index: AQHUbDXosCMLZiTdhUub2GBbIxhAKqUwKetQ Date: Thu, 25 Oct 2018 16:47:09 +0000 Message-ID: <039ED4275CED7440929022BC67E70611532DB803@SHSMSX103.ccr.corp.intel.com> References: <1540453252-128654-1-git-send-email-beilei.xing@intel.com> In-Reply-To: <1540453252-128654-1-git-send-email-beilei.xing@intel.com> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-titus-metadata-40: eyJDYXRlZ29yeUxhYmVscyI6IiIsIk1ldGFkYXRhIjp7Im5zIjoiaHR0cDpcL1wvd3d3LnRpdHVzLmNvbVwvbnNcL0ludGVsMyIsImlkIjoiNzJiYjIwZWQtNWQ4OS00MTNhLThmYWEtZTMxZGM2MzUxYzg0IiwicHJvcHMiOlt7Im4iOiJDVFBDbGFzc2lmaWNhdGlvbiIsInZhbHMiOlt7InZhbHVlIjoiQ1RQX05UIn1dfV19LCJTdWJqZWN0TGFiZWxzIjpbXSwiVE1DVmVyc2lvbiI6IjE3LjEwLjE4MDQuNDkiLCJUcnVzdGVkTGFiZWxIYXNoIjoieXhKT2hqOXZSU2ZQbXUrTnlCdVdPRXZVT3pVTzVOb2l5aHQ1bDRUaElRZG1MdFRRUHI4bGg1YjZKUWZnTEpvTCJ9 x-ctpclassification: CTP_NT dlp-product: dlpe-windows dlp-version: 11.0.400.15 dlp-reaction: no-action x-originating-ip: [10.239.127.40] Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Subject: Re: [dpdk-dev] [PATCH] net/i40e: fix Rx instability with vector mode X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 25 Oct 2018 16:47:13 -0000 > -----Original Message----- > From: Xing, Beilei > Sent: Thursday, October 25, 2018 2:41 AM > To: Zhang, Qi Z > Cc: dev@dpdk.org; stable@dpdk.org > Subject: [PATCH] net/i40e: fix Rx instability with vector mode >=20 > Previously, there is instability during vector Rx if descriptor number is= not > power of 2, e.g. process hang and some Rx packets are unexpectedly empty. > That's because vector Rx mode assumes Rx descriptor number is power of 2 > when doing bit mask. > This patch allows vector mode only when the number of Rx descriptor is > power of 2. >=20 > Fixes: 8e109464c022 ("i40e: allow vector Rx and Tx usage") > Fixes: a3c83a2527e1 ("net/i40e: enable runtime queue setup") > Cc: stable@dpdk.org >=20 > Signed-off-by: Beilei Xing > --- > doc/guides/nics/i40e.rst | 7 +++++++ > drivers/net/i40e/i40e_rxtx.c | 18 +++++++++++++++++- > 2 files changed, 24 insertions(+), 1 deletion(-) >=20 > diff --git a/doc/guides/nics/i40e.rst b/doc/guides/nics/i40e.rst index > ab3928a..bfacbd1 100644 > --- a/doc/guides/nics/i40e.rst > +++ b/doc/guides/nics/i40e.rst > @@ -172,6 +172,13 @@ Runtime Config Options >=20 > -w 84:00.0,use-latest-supported-vec=3D1 >=20 > +Vector RX Pre-conditions > +~~~~~~~~~~~~~~~~~~~~~~~~ > +For Vector RX it is assumed that the number of descriptor rings will be > +a power of 2. With this pre-condition, the ring pointer can easily > +scroll back to the head after hitting the tail without a conditional > +check. In addition Vector RX can use this assumption to do a bit mask us= ing > ``ring_size - 1``. > + > Driver compilation and testing > ------------------------------ >=20 > diff --git a/drivers/net/i40e/i40e_rxtx.c b/drivers/net/i40e/i40e_rxtx.c = index > a827456..aa46d83 100644 > --- a/drivers/net/i40e/i40e_rxtx.c > +++ b/drivers/net/i40e/i40e_rxtx.c > @@ -1735,10 +1735,17 @@ i40e_dev_rx_queue_setup_runtime(struct > rte_eth_dev *dev, > * i40e_set_rx_function. > */ > ad->rx_bulk_alloc_allowed =3D true; > - ad->rx_vec_allowed =3D true; > dev->data->scattered_rx =3D use_scattered_rx; > if (use_def_burst_func) > ad->rx_bulk_alloc_allowed =3D false; > + /** > + * Vector mode is allowed only when number of Rx queue > + * descriptor is a power of 2. > + */ > + if ((rxq->nb_rx_desc & (rxq->nb_rx_desc - 1))) > + ad->rx_vec_allowed =3D false; > + else > + ad->rx_vec_allowed =3D true; > i40e_set_rx_function(dev); > return 0; > } > @@ -1811,6 +1818,15 @@ i40e_dev_rx_queue_setup(struct rte_eth_dev > *dev, > return -EINVAL; > } >=20 > + /** > + * Vector mode is allowed only when number of Rx queue > + * descriptor is a power of 2. > + */ > + if ((nb_desc & (nb_desc - 1))) > + ad->rx_vec_allowed =3D false; > + else > + ad->rx_vec_allowed =3D true; rx_vec_allowed will be overwritten unexpectedly for multi-queues case We may only to overwrite with below condition check. If (first_queue || ad->rx_vec_allowed) ad->rx_vec_allowed =3D ! (nb_desc & (nb_desc - 1)); > + > /* Free memory if needed */ > if (dev->data->rx_queues[queue_idx]) { > i40e_dev_rx_queue_release(dev->data->rx_queues[queue_idx]); > -- > 2.5.5