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 4283DA0613 for ; Fri, 27 Sep 2019 07:42:53 +0200 (CEST) Received: from [92.243.14.124] (localhost [127.0.0.1]) by dpdk.org (Postfix) with ESMTP id AB2A32C58; Fri, 27 Sep 2019 07:42:33 +0200 (CEST) Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by dpdk.org (Postfix) with ESMTP id 3F75A2C58 for ; Fri, 27 Sep 2019 07:42:31 +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 C3531142F; Thu, 26 Sep 2019 22:42:30 -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 2BD0F3F67D; Thu, 26 Sep 2019 22:45:04 -0700 (PDT) From: Gavin Hu To: dev@dpdk.org Cc: nd@arm.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: Fri, 27 Sep 2019 13:41:40 +0800 Message-Id: <1569562904-43950-4-git-send-email-gavin.hu@arm.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1569562904-43950-1-git-send-email-gavin.hu@arm.com> References: <1569562904-43950-1-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 v7 3/7] 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 ++++++++++++++++++++++ 1 file changed, 26 insertions(+) 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..b61c055 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. + */ +#ifndef RTE_FORCE_INTRINSICS +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; -- 2.7.4