From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mga09.intel.com (mga09.intel.com [134.134.136.24]) by dpdk.org (Postfix) with ESMTP id 19AEE333 for ; Wed, 24 Sep 2014 10:58:27 +0200 (CEST) Received: from orsmga001.jf.intel.com ([10.7.209.18]) by orsmga102.jf.intel.com with ESMTP; 24 Sep 2014 01:58:24 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.04,587,1406617200"; d="scan'208";a="578104089" Received: from irsmsx101.ger.corp.intel.com ([163.33.3.153]) by orsmga001.jf.intel.com with ESMTP; 24 Sep 2014 02:04:03 -0700 Received: from irsmsx107.ger.corp.intel.com (163.33.3.99) by IRSMSX101.ger.corp.intel.com (163.33.3.153) with Microsoft SMTP Server (TLS) id 14.3.195.1; Wed, 24 Sep 2014 10:03:21 +0100 Received: from irsmsx103.ger.corp.intel.com ([169.254.3.112]) by IRSMSX107.ger.corp.intel.com ([169.254.10.108]) with mapi id 14.03.0195.001; Wed, 24 Sep 2014 10:03:21 +0100 From: "Richardson, Bruce" To: Neil Horman Thread-Topic: [dpdk-dev] [PATCH v2 3/5] testpmd: Change rxfreet default to 32 Thread-Index: AQHP1x64pnhngwnmO0eRzTenUB9NPZwO4VGAgAEcskA= Date: Wed, 24 Sep 2014 09:03:20 +0000 Message-ID: <59AF69C657FD0841A61C55336867B5B03440521B@IRSMSX103.ger.corp.intel.com> References: <1410948102-12740-1-git-send-email-bruce.richardson@intel.com> <1411470497-10209-1-git-send-email-bruce.richardson@intel.com> <1411470497-10209-4-git-send-email-bruce.richardson@intel.com> <20140923170231.GC12884@hmsreliant.think-freely.org> In-Reply-To: <20140923170231.GC12884@hmsreliant.think-freely.org> Accept-Language: en-GB, en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [163.33.239.181] Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Cc: "dev@dpdk.org" Subject: Re: [dpdk-dev] [PATCH v2 3/5] testpmd: Change rxfreet default to 32 X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: patches and discussions about DPDK List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 24 Sep 2014 08:58:28 -0000 > -----Original Message----- > From: Neil Horman [mailto:nhorman@tuxdriver.com] > Sent: Tuesday, September 23, 2014 6:03 PM > To: Richardson, Bruce > Cc: dev@dpdk.org > Subject: Re: [dpdk-dev] [PATCH v2 3/5] testpmd: Change rxfreet default to= 32 >=20 > On Tue, Sep 23, 2014 at 12:08:15PM +0100, Bruce Richardson wrote: > > To improve performance by using bulk alloc or vectored RX routines, we > > need to set rx free threshold (rxfreet) value to 32, so make this the > > testpmd default. > > > > Thirty-two is the minimum setting needed to enable either the > > bulk alloc or vector RX routines inside the ixgbe driver, so it's > > best made the default for that reason. Please see > > "check_rx_burst_bulk_alloc_preconditions()" in ixgbe_rxtx.c, and > > RX function assignment logic in "ixgbe_dev_rx_queue_setup()" in > > the same file. > > > > The difference in IO performance for testpmd when called without any > > optional parameters, and using 10G NICs using the ixgbe driver, can be > > significant - approx 25% or more. > > > > Updates in V2: > > * Updated commit message with additional details > > > > Signed-off-by: Bruce Richardson > > --- > > app/test-pmd/testpmd.c | 4 +++- > > 1 file changed, 3 insertions(+), 1 deletion(-) > > > > diff --git a/app/test-pmd/testpmd.c b/app/test-pmd/testpmd.c > > index 9f6cdc4..f76406f 100644 > > --- a/app/test-pmd/testpmd.c > > +++ b/app/test-pmd/testpmd.c > > @@ -225,7 +225,9 @@ struct rte_eth_thresh tx_thresh =3D { > > /* > > * Configurable value of RX free threshold. > > */ > > -uint16_t rx_free_thresh =3D 0; /* Immediately free RX descriptors by d= efault. */ > > +uint16_t rx_free_thresh =3D 32; /* Refill RX descriptors once every 32= packets, > > + This setting is needed for ixgbe to enable bulk alloc or vector > > + receive functionality. */ >=20 > I thought we were talking about making this a pmd private selectable item= , or > allowing a reserved "let the pmd decide" setting. Or are we saving that = for a > later time? >=20 Yes, we are looking at that - and hopefully we can also get a patch for tha= t in for our next release. However, I've left this patch in just in case th= at doesn't actually happen, as the performance improvements for 10G are jus= t too good to leave aside for the sake of a 1-line change. Ideally, I'd lik= e this go to in, and then be replaced by a "proper" fix. /Bruce > Neil >=20 > > > > /* > > * Configurable value of RX drop enable. > > -- > > 1.9.3 > > > >