From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from dpdk.org (dpdk.org [92.243.14.124]) by inbox.dpdk.org (Postfix) with ESMTP id C41DBA3201 for ; Mon, 21 Oct 2019 11:48:50 +0200 (CEST) Received: from [92.243.14.124] (localhost [127.0.0.1]) by dpdk.org (Postfix) with ESMTP id 7C2E11BE9C; Mon, 21 Oct 2019 11:48:40 +0200 (CEST) Received: from foss.arm.com (unknown [217.140.110.172]) by dpdk.org (Postfix) with ESMTP id F07631BEA4 for ; Mon, 21 Oct 2019 11:48:38 +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 D9C1B105A; Mon, 21 Oct 2019 02:48:29 -0700 (PDT) Received: from net-arm-thunderx2-01.test.ast.arm.com (net-arm-thunderx2-01.shanghai.arm.com [10.169.40.40]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 071FF3F718; Mon, 21 Oct 2019 02:48:25 -0700 (PDT) From: Gavin Hu To: dev@dpdk.org Cc: nd@arm.com, david.marchand@redhat.com, konstantin.ananyev@intel.com, thomas@monjalon.net, stephen@networkplumber.org, hemant.agrawal@nxp.com, jerinj@marvell.com, pbhagavatula@marvell.com, Honnappa.Nagarahalli@arm.com, ruifeng.wang@arm.com, phil.yang@arm.com, steve.capper@arm.com Date: Mon, 21 Oct 2019 17:47:56 +0800 Message-Id: <1571651279-51857-4-git-send-email-gavin.hu@arm.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1571651279-51857-1-git-send-email-gavin.hu@arm.com> References: <1571651279-51857-1-git-send-email-gavin.hu@arm.com> In-Reply-To: <1561911676-37718-1-git-send-email-gavin.hu@arm.com> References: <1561911676-37718-1-git-send-email-gavin.hu@arm.com> Subject: [dpdk-dev] [PATCH v8 3/6] spinlock: use wfe to reduce contention on aarch64 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" In acquiring a spinlock, cores repeatedly poll the lock variable. This is replaced by rte_wait_until_equal API. Running the micro benchmarking and the testpmd and l3fwd traffic tests on ThunderX2, Ampere eMAG80 and Arm N1SDP, everything went well and no notable performance gain nor degradation was measured. Signed-off-by: Gavin Hu Reviewed-by: Ruifeng Wang Reviewed-by: Phil Yang Reviewed-by: Steve Capper Reviewed-by: Ola Liljedahl Reviewed-by: Honnappa Nagarahalli Tested-by: Pavan Nikhilesh --- .../common/include/arch/arm/rte_spinlock.h | 26 ++++++++++++++++++++++ .../common/include/generic/rte_spinlock.h | 2 +- 2 files changed, 27 insertions(+), 1 deletion(-) diff --git a/lib/librte_eal/common/include/arch/arm/rte_spinlock.h b/lib/librte_eal/common/include/arch/arm/rte_spinlock.h index 1a6916b..c69bed1 100644 --- a/lib/librte_eal/common/include/arch/arm/rte_spinlock.h +++ b/lib/librte_eal/common/include/arch/arm/rte_spinlock.h @@ -16,6 +16,32 @@ extern "C" { #include #include "generic/rte_spinlock.h" +/* armv7a does support WFE, but an explicit wake-up signal using SEV is + * required (must be preceded by DSB to drain the store buffer) and + * this is less performant, so keep armv7a implementation unchanged. + */ +#ifdef RTE_ARM_USE_WFE +static inline void +rte_spinlock_lock(rte_spinlock_t *sl) +{ + unsigned int tmp; + /* http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc. + * faqs/ka16809.html + */ + asm volatile( + "1: ldaxr %w[tmp], %w[locked]\n" + "cbnz %w[tmp], 2f\n" + "stxr %w[tmp], %w[one], %w[locked]\n" + "cbnz %w[tmp], 1b\n" + "ret\n" + "2: sevl\n" + "wfe\n" + "jmp 1b\n" + : [tmp] "=&r" (tmp), [locked] "+Q"(sl->locked) + : [one] "r" (1) +} +#endif + static inline int rte_tm_supported(void) { return 0; diff --git a/lib/librte_eal/common/include/generic/rte_spinlock.h b/lib/librte_eal/common/include/generic/rte_spinlock.h index 87ae7a4..cf57c72 100644 --- a/lib/librte_eal/common/include/generic/rte_spinlock.h +++ b/lib/librte_eal/common/include/generic/rte_spinlock.h @@ -57,7 +57,7 @@ rte_spinlock_init(rte_spinlock_t *sl) static inline void rte_spinlock_lock(rte_spinlock_t *sl); -#ifdef RTE_FORCE_INTRINSICS +#if defined(RTE_FORCE_INTRINSICS) && !defined(RTE_ARM_USE_WFE) static inline void rte_spinlock_lock(rte_spinlock_t *sl) { -- 2.7.4