From patchwork Thu Sep 11 07:48:31 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Hiroshi Shimamoto X-Patchwork-Id: 337 Return-Path: X-Original-To: patchwork@dpdk.org Delivered-To: patchwork@dpdk.org Received: from [92.243.14.124] (localhost [IPv6:::1]) by dpdk.org (Postfix) with ESMTP id 384F55909; Thu, 11 Sep 2014 09:52:50 +0200 (CEST) Received: from tyo202.gate.nec.co.jp (TYO202.gate.nec.co.jp [210.143.35.52]) by dpdk.org (Postfix) with ESMTP id 128495901 for ; Thu, 11 Sep 2014 09:52:47 +0200 (CEST) Received: from mailgate3.nec.co.jp ([10.7.69.195]) by tyo202.gate.nec.co.jp (8.13.8/8.13.4) with ESMTP id s8B7vxMc013433 for ; Thu, 11 Sep 2014 16:57:59 +0900 (JST) Received: from mailsv.nec.co.jp (imss62.nec.co.jp [10.7.69.157]) by mailgate3.nec.co.jp (8.11.7/3.7W-MAILGATE-NEC) with ESMTP id s8B7vxx08641 for ; Thu, 11 Sep 2014 16:57:59 +0900 (JST) Received: from mail02.kamome.nec.co.jp (mail02.kamome.nec.co.jp [10.25.43.5]) by mailsv.nec.co.jp (8.13.8/8.13.4) with ESMTP id s8B7vw8V021635 for ; Thu, 11 Sep 2014 16:57:58 +0900 (JST) Received: from bpxc99gp.gisp.nec.co.jp ([10.38.151.143] [10.38.151.143]) by mail03.kamome.nec.co.jp with ESMTP id BT-MMP-1866691; Thu, 11 Sep 2014 16:48:32 +0900 Received: from BPXM14GP.gisp.nec.co.jp ([169.254.1.238]) by BPXC15GP.gisp.nec.co.jp ([10.38.151.143]) with mapi id 14.02.0328.011; Thu, 11 Sep 2014 16:48:31 +0900 From: Hiroshi Shimamoto To: "dev@dpdk.org" Thread-Topic: [memnic PATCH 4/7] pmd: use compiler barrier Thread-Index: Ac/NlMCoOHz0IbAaSSqSD302Hm2F/A== Date: Thu, 11 Sep 2014 07:48:31 +0000 Message-ID: <7F861DC0615E0C47A872E6F3C5FCDDBD011A9934@BPXM14GP.gisp.nec.co.jp> Accept-Language: ja-JP, en-US Content-Language: ja-JP X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [10.205.5.123] MIME-Version: 1.0 Cc: Hayato Momma Subject: [dpdk-dev] [memnic PATCH 4/7] pmd: use compiler barrier 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: , Errors-To: dev-bounces@dpdk.org Sender: "dev" From: Hiroshi Shimamoto x86 can keep store ordering with standard operations. Using memory barrier is much expensive in main packet processing loop. Removing this improves xmit/recv packet performance. We can see performance improvements with memnic-tester. Using Xeon E5-2697 v2 @ 2.70GHz, 4 vCPU. size | before | after 64 | 4.18Mpps | 4.59Mpps 128 | 3.85Mpps | 4.87Mpps 256 | 4.01Mpps | 4.72Mpps 512 | 3.52Mpps | 4.41Mpps 1024 | 3.18Mpps | 3.64Mpps 1280 | 2.86Mpps | 3.15Mpps 1518 | 2.59Mpps | 2.87Mpps Note: we have to take care if we use temporal cache. Signed-off-by: Hiroshi Shimamoto Reviewed-by: Hayato Momma --- pmd/pmd_memnic.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/pmd/pmd_memnic.c b/pmd/pmd_memnic.c index 8341da7..c22a14d 100644 --- a/pmd/pmd_memnic.c +++ b/pmd/pmd_memnic.c @@ -316,7 +316,7 @@ static uint16_t memnic_recv_pkts(void *rx_queue, bytes += p->len; drop: - rte_mb(); + rte_compiler_barrier(); p->status = MEMNIC_PKT_ST_FREE; if (++idx >= MEMNIC_NR_PACKET) @@ -403,7 +403,7 @@ retry: pkts++; bytes += pkt_len; - rte_mb(); + rte_compiler_barrier(); p->status = MEMNIC_PKT_ST_FILLED; rte_pktmbuf_free(tx_pkts[nr]);