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 A7F476A87 for ; Tue, 30 Sep 2014 15:32:59 +0200 (CEST) Received: from fmsmga003.fm.intel.com ([10.253.24.29]) by fmsmga101.fm.intel.com with ESMTP; 30 Sep 2014 06:39:39 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.97,862,1389772800"; d="scan'208";a="393568865" Received: from fmsmsx106.amr.corp.intel.com ([10.18.124.204]) by FMSMGA003.fm.intel.com with ESMTP; 30 Sep 2014 06:33:21 -0700 Received: from fmsmsx101.amr.corp.intel.com (10.18.124.199) by FMSMSX106.amr.corp.intel.com (10.18.124.204) with Microsoft SMTP Server (TLS) id 14.3.195.1; Tue, 30 Sep 2014 06:39:39 -0700 Received: from shsmsx102.ccr.corp.intel.com (10.239.4.154) by fmsmsx101.amr.corp.intel.com (10.18.124.199) with Microsoft SMTP Server (TLS) id 14.3.195.1; Tue, 30 Sep 2014 06:39:38 -0700 Received: from shsmsx101.ccr.corp.intel.com ([169.254.1.203]) by shsmsx102.ccr.corp.intel.com ([169.254.2.192]) with mapi id 14.03.0195.001; Tue, 30 Sep 2014 21:39:37 +0800 From: "Xie, Huawei" To: Hiroshi Shimamoto , "dev@dpdk.org" Thread-Topic: [memnic PATCH v2 6/7] pmd: add branch hint in recv/xmit Thread-Index: Ac/cn7cr+0i1sUkPRO2iopF1mOwIlQAE78KA Date: Tue, 30 Sep 2014 13:39:36 +0000 Message-ID: References: <7F861DC0615E0C47A872E6F3C5FCDDBD02AE26C5@BPXM14GP.gisp.nec.co.jp> In-Reply-To: <7F861DC0615E0C47A872E6F3C5FCDDBD02AE26C5@BPXM14GP.gisp.nec.co.jp> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [10.239.127.40] Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Cc: Hayato Momma Subject: Re: [dpdk-dev] [memnic PATCH v2 6/7] pmd: add branch hint in recv/xmit 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: Tue, 30 Sep 2014 13:33:00 -0000 The patch is ok. For the commit message, is it better=20 "to reduce branch mispredication"? > -----Original Message----- > From: dev [mailto:dev-bounces@dpdk.org] On Behalf Of Hiroshi Shimamoto > Sent: Tuesday, September 30, 2014 7:15 PM > To: dev@dpdk.org > Cc: Hayato Momma > Subject: [dpdk-dev] [memnic PATCH v2 6/7] pmd: add branch hint in recv/xm= it >=20 > From: Hiroshi Shimamoto >=20 > To reduce instruction cache miss, add branch condition hints into > recv/xmit functions. This improves a bit performance. >=20 > We can see performance improvements with memnic-tester. > Using Xeon E5-2697 v2 @ 2.70GHz, 4 vCPU. > size | before | after > 64 | 5.54Mpps | 5.55Mpps > 128 | 5.46Mpps | 5.44Mpps > 256 | 5.21Mpps | 5.22Mpps > 512 | 4.50Mpps | 4.52Mpps > 1024 | 3.71Mpps | 3.73Mpps > 1280 | 3.21Mpps | 3.22Mpps > 1518 | 2.92Mpps | 2.93Mpps >=20 > Signed-off-by: Hiroshi Shimamoto > Reviewed-by: Hayato Momma > --- > pmd/pmd_memnic.c | 18 +++++++++--------- > 1 file changed, 9 insertions(+), 9 deletions(-) >=20 > diff --git a/pmd/pmd_memnic.c b/pmd/pmd_memnic.c > index 7fc3093..875d3ea 100644 > --- a/pmd/pmd_memnic.c > +++ b/pmd/pmd_memnic.c > @@ -289,26 +289,26 @@ static uint16_t memnic_recv_pkts(void *rx_queue, > int idx, next; > struct rte_eth_stats *st =3D &adapter->stats[rte_lcore_id()]; >=20 > - if (!adapter->nic->hdr.valid) > + if (unlikely(!adapter->nic->hdr.valid)) > return 0; >=20 > pkts =3D bytes =3D errs =3D 0; > idx =3D adapter->up_idx; > for (nr =3D 0; nr < nb_pkts; nr++) { > p =3D &data->packets[idx]; > - if (p->status !=3D MEMNIC_PKT_ST_FILLED) > + if (unlikely(p->status !=3D MEMNIC_PKT_ST_FILLED)) > break; > /* prefetch the next area */ > next =3D idx; > - if (++next >=3D MEMNIC_NR_PACKET) > + if (unlikely(++next >=3D MEMNIC_NR_PACKET)) > next =3D 0; > rte_prefetch0(&data->packets[next]); > - if (p->len > framesz) { > + if (unlikely(p->len > framesz)) { > errs++; > goto drop; > } > mb =3D rte_pktmbuf_alloc(adapter->mp); > - if (!mb) > + if (unlikely(!mb)) > break; >=20 > rte_memcpy(rte_pktmbuf_mtod(mb, void *), p->data, p->len); > @@ -350,7 +350,7 @@ static uint16_t memnic_xmit_pkts(void *tx_queue, > uint64_t pkts, bytes, errs; > uint32_t framesz =3D adapter->framesz; >=20 > - if (!adapter->nic->hdr.valid) > + if (unlikely(!adapter->nic->hdr.valid)) > return 0; >=20 > pkts =3D bytes =3D errs =3D 0; > @@ -360,7 +360,7 @@ static uint16_t memnic_xmit_pkts(void *tx_queue, > struct rte_mbuf *sg; > void *ptr; >=20 > - if (pkt_len > framesz) { > + if (unlikely(pkt_len > framesz)) { > errs++; > break; > } > @@ -379,7 +379,7 @@ retry: > goto retry; > } >=20 > - if (idx !=3D ACCESS_ONCE(adapter->down_idx)) { > + if (unlikely(idx !=3D ACCESS_ONCE(adapter->down_idx))) { > /* > * host freed this and got false positive, > * need to recover the status and retry. > @@ -388,7 +388,7 @@ retry: > goto retry; > } >=20 > - if (++idx >=3D MEMNIC_NR_PACKET) > + if (unlikely(++idx >=3D MEMNIC_NR_PACKET)) > idx =3D 0; > adapter->down_idx =3D idx; >=20 > -- > 1.8.3.1