From patchwork Mon Jul 6 23:43:31 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Honnappa Nagarahalli X-Patchwork-Id: 234899 Delivered-To: patch@linaro.org Received: by 2002:a92:d244:0:0:0:0:0 with SMTP id v4csp411190ilg; Mon, 6 Jul 2020 16:43:52 -0700 (PDT) X-Google-Smtp-Source: ABdhPJxfXwVwbdLVicE9C2v3HSlIlEqtKlITsFDs1kwvYWTNW2suMOCIjK8f6DKcUcCcoZPA44pL X-Received: by 2002:a25:30d5:: with SMTP id w204mr25310735ybw.405.1594079032127; Mon, 06 Jul 2020 16:43:52 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1594079032; cv=none; d=google.com; s=arc-20160816; b=FiIvsJy6xsTAQfNzxzGHavRpksLF+r182ns90K42UICYujjiwjWid6TrJPnurUDipI tifPHX0mG4s2V2sD+ZiFSfLzzO2YZe9UqzAcPTRrR3rLvWlcxSEgl2FoA2JrqKWdGol1 T9ACjf4dmqJ0f4KGXTSMRmAEYLsBrsqu0K4oEi9F9J1L4Z0cLELE/P1ZRzLe0mYSNFZl IcHwv5Pvucr6fHRZWMyrd0eWhSuHcjDd2POnPZ2+30bLwu5H/Qoj8N4SniEXH3M0vl+S x+e92sCtSb0nPG0QLL/fuNwSH3i5FkLaTx4YJn3GNDO2aYEWldyOC90BharFCMfEr4tb 03zA== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=sender:errors-to:list-subscribe:list-help:list-post:list-archive :list-unsubscribe:list-id:precedence:subject:references:in-reply-to :message-id:date:cc:to:from; bh=aSRPs1KfPYlb/C8yuxHSi+HPKYEHFzGANuANTRuIIuI=; b=KaciL88zdJVUa7i7AhHkk2oWaH+vmul2SxmvcR0ChnwiZ19UTpJ9vn/MjBweHaD3+C CSHNtdaJ7EYmlSJH7+ByToH5yhsU917+/92tSzodWN5er3KfxJzDtIjhDibjCBSzXyhM dTAbJVSm8aSmuHuUT4muxQOUBpenqKLP3y1Poop0zthISqU+jrRqHCflY8eTbTPeI7fg ARAfnKuAzi10IZ0e0TKKAkrFbX35qXaiixe+L32MgtlV0Fv/4B+5vIhKND+qHVxfXbdF bcUmUYrjD8LPKEyJZjzY4KwhKRl7cFpXFnEk7064+H/uOpycyUrWZUO0pyhHMeo/3I7y drpQ== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: domain of dev-bounces@dpdk.org designates 92.243.14.124 as permitted sender) smtp.mailfrom=dev-bounces@dpdk.org Return-Path: Received: from dpdk.org (dpdk.org. [92.243.14.124]) by mx.google.com with ESMTP id a12si5079542ybp.210.2020.07.06.16.43.51; Mon, 06 Jul 2020 16:43:52 -0700 (PDT) Received-SPF: pass (google.com: domain of dev-bounces@dpdk.org designates 92.243.14.124 as permitted sender) client-ip=92.243.14.124; Authentication-Results: mx.google.com; spf=pass (google.com: domain of dev-bounces@dpdk.org designates 92.243.14.124 as permitted sender) smtp.mailfrom=dev-bounces@dpdk.org Received: from [92.243.14.124] (localhost [127.0.0.1]) by dpdk.org (Postfix) with ESMTP id 518531DC7E; Tue, 7 Jul 2020 01:43:50 +0200 (CEST) Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by dpdk.org (Postfix) with ESMTP id 2FA081DC0F for ; Tue, 7 Jul 2020 01:43:49 +0200 (CEST) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 908E4C0A; Mon, 6 Jul 2020 16:43:48 -0700 (PDT) Received: from qc2400f-1.austin.arm.com (qc2400f-1.austin.arm.com [10.118.12.27]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 7CB693F718; Mon, 6 Jul 2020 16:43:48 -0700 (PDT) From: Honnappa Nagarahalli To: dev@dpdk.org, honnappa.nagarahalli@arm.com, ruifeng.wang@arm.com, jerinj@marvell.com, hemant.agrawal@nxp.com, ajit.khaparde@broadcom.com, igorch@amazon.com, thomas@monjalon.net, viacheslavo@mellanox.com, arybchenko@solarflare.com, bruce.richardson@intel.com Cc: nd@arm.com Date: Mon, 6 Jul 2020 18:43:31 -0500 Message-Id: <20200706234333.26310-1-honnappa.nagarahalli@arm.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20200410164127.54229-1-gavin.hu@arm.com> References: <20200410164127.54229-1-gavin.hu@arm.com> Subject: [dpdk-dev] [PATCH v4 1/3] eal: adjust barriers for IO on Armv8-a 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: , Errors-To: dev-bounces@dpdk.org Sender: "dev" Change the barrier APIs for IO to reflect that Armv8-a is other-multi-copy atomicity memory model. Armv8-a memory model has been strengthened to require other-multi-copy atomicity. This property requires memory accesses from an observer to become visible to all other observers simultaneously [3]. This means a) A write arriving at an endpoint shared between multiple CPUs is visible to all CPUs b) A write that is visible to all CPUs is also visible to all other observers in the shareability domain This allows for using cheaper DMB instructions in the place of DSB for devices that are visible to all CPUs (i.e. devices that DPDK caters to). Please refer to [1], [2] and [3] for more information. [1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=22ec71615d824f4f11d38d0e55a88d8956b7e45f [2] https://www.youtube.com/watch?v=i6DayghhA8Q [3] https://www.cl.cam.ac.uk/~pes20/armv8-mca/ Signed-off-by: Honnappa Nagarahalli Acked-by: Jerin Jacob Tested-by: Ruifeng Wang --- lib/librte_eal/arm/include/rte_atomic_64.h | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) -- 2.17.1 diff --git a/lib/librte_eal/arm/include/rte_atomic_64.h b/lib/librte_eal/arm/include/rte_atomic_64.h index 7b7099cdc..e42f69edc 100644 --- a/lib/librte_eal/arm/include/rte_atomic_64.h +++ b/lib/librte_eal/arm/include/rte_atomic_64.h @@ -1,6 +1,6 @@ /* SPDX-License-Identifier: BSD-3-Clause * Copyright(c) 2015 Cavium, Inc - * Copyright(c) 2019 Arm Limited + * Copyright(c) 2020 Arm Limited */ #ifndef _RTE_ATOMIC_ARM64_H_ @@ -19,11 +19,11 @@ extern "C" { #include #include -#define rte_mb() asm volatile("dsb sy" : : : "memory") +#define rte_mb() asm volatile("dmb osh" : : : "memory") -#define rte_wmb() asm volatile("dsb st" : : : "memory") +#define rte_wmb() asm volatile("dmb oshst" : : : "memory") -#define rte_rmb() asm volatile("dsb ld" : : : "memory") +#define rte_rmb() asm volatile("dmb oshld" : : : "memory") #define rte_smp_mb() asm volatile("dmb ish" : : : "memory") @@ -37,9 +37,9 @@ extern "C" { #define rte_io_rmb() rte_rmb() -#define rte_cio_wmb() asm volatile("dmb oshst" : : : "memory") +#define rte_cio_wmb() rte_wmb() -#define rte_cio_rmb() asm volatile("dmb oshld" : : : "memory") +#define rte_cio_rmb() rte_rmb() /*------------------------ 128 bit atomic operations -------------------------*/