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 A4C1AA2EEB for ; Thu, 12 Sep 2019 13:25:09 +0200 (CEST) Received: from [92.243.14.124] (localhost [127.0.0.1]) by dpdk.org (Postfix) with ESMTP id 075AF1E939; Thu, 12 Sep 2019 13:25:08 +0200 (CEST) Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by dpdk.org (Postfix) with ESMTP id 28CC61E8BC for ; Thu, 12 Sep 2019 13:25:06 +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 1373528; Thu, 12 Sep 2019 04:25:05 -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 46D703F67D; Thu, 12 Sep 2019 04:25:03 -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 Date: Thu, 12 Sep 2019 19:24:25 +0800 Message-Id: <1568287473-55306-1-git-send-email-gavin.hu@arm.com> X-Mailer: git-send-email 2.7.4 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 v5 0/8] use WFE for 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" V5: - add doxygen comments for the new APIs - spinlock early exit without wfe if the spinlock not taken by others. V4: - rename the config as CONFIG_RTE_ARM_USE_WFE to indicate it applys to arm only - introduce a macro for assembly Skelton to reduce the duplication of code - add one patch for nxp fslmc to address a compiling error V3: - Convert RFCs to patches V2: - Use inline functions instead of marcos - Add load and compare in the beginning of the APIs - Fix some style errors in asm inline V1: - Add the new APIs and use it for ring and locks DPDK has multiple use cases where the core repeatedly polls a location in memory. This polling results in many cache and memory transactions. Arm architecture provides WFE (Wait For Event) instruction, which allows the cpu core to enter a low power state until woken up by the update to the memory location being polled. Thus reducing the cache and memory transactions. x86 has the PAUSE hint instruction to reduce such overhead. The rte_wait_until_equal_xxx APIs abstract the functionality of 'polling for a memory location to become equal to a given value'. For non-Arm platforms, these APIs are just wrappers around do-while loop with rte_pause, so there are no performance differences. For Arm platforms, use of WFE can be configured using CONFIG_RTE_USE_WFE option. It is disabled by default. Currently, use of WFE is supported only for aarch64 platforms. armv7 platforms do support the WFE instruction, but they require explicit wake up events(sev) and are less performannt. Testing shows that, performance varies across different platforms, with some showing degradation. CONFIG_RTE_ARM_USE_WFE should be enabled depending on the performance benchmarking on the target platforms. Power saving should be an bonus, but currenly we don't have ways to characterize that. Gavin Hu (8): config: add WFE config entry for aarch64 bus/fslmc: fix the conflicting dmb function eal: add the APIs to wait until equal spinlock: use wfe to reduce contention on aarch64 ticketlock: use new API to reduce contention on aarch64 ring: use wfe to wait for ring tail update on aarch64 net/thunderx: use new API to save cycles on aarch64 event/opdl: use new API to save cycles on aarch64 config/arm/meson.build | 1 + config/common_base | 6 + drivers/bus/fslmc/mc/fsl_mc_sys.h | 10 +- drivers/bus/fslmc/mc/mc_sys.c | 3 +- drivers/event/opdl/opdl_ring.c | 5 +- drivers/net/thunderx/nicvf_rxtx.c | 3 +- .../common/include/arch/arm/rte_pause_64.h | 30 +++++ .../common/include/arch/arm/rte_spinlock.h | 26 ++++ lib/librte_eal/common/include/generic/rte_pause.h | 146 ++++++++++++++++++++- .../common/include/generic/rte_ticketlock.h | 3 +- lib/librte_ring/rte_ring_c11_mem.h | 4 +- lib/librte_ring/rte_ring_generic.h | 3 +- 12 files changed, 223 insertions(+), 17 deletions(-) -- 2.7.4