From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mails.dpdk.org (mails.dpdk.org [217.70.189.124]) by inbox.dpdk.org (Postfix) with ESMTP id A037442C99; Mon, 12 Jun 2023 21:48:08 +0200 (CEST) Received: from mails.dpdk.org (localhost [127.0.0.1]) by mails.dpdk.org (Postfix) with ESMTP id 8F85A410F9; Mon, 12 Jun 2023 21:48:08 +0200 (CEST) Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by mails.dpdk.org (Postfix) with ESMTP id 87F7C40689 for ; Mon, 12 Jun 2023 21:48:07 +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 1D90D1FB; Mon, 12 Jun 2023 12:48:52 -0700 (PDT) Received: from ampere-altra-2-1.usa.Arm.com (ampere-altra-2-1.usa.arm.com [10.118.91.158]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 0133E3F5A1; Mon, 12 Jun 2023 12:48:06 -0700 (PDT) From: Wathsala Vithanage To: honnappa.nagarahalli@arm.com, konstantin.v.ananyev@yandex.ru, thomas@monjalon.net, ruifeng.wang@arm.com Cc: dev@dpdk.org, nd@arm.com, Wathsala Vithanage Subject: [RFC] ring: remove unnecessary fences in C11 ring for performance Date: Mon, 12 Jun 2023 19:47:16 +0000 Message-Id: <20230612194716.1050379-2-wathsala.vithanage@arm.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20230612194716.1050379-1-wathsala.vithanage@arm.com> References: <20230612194716.1050379-1-wathsala.vithanage@arm.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces@dpdk.org For improved performance over the current C11 based ring implementation, two ACQUIRE fences between the load of the old_head and the load of the const_tail in __rte_ring_move_prod_head and the load of old_head and load of the prod_tail in __rte_ring_move_cons_head functions have been removed. These two fences are not required for the safety of the ring library. Signed-off-by: Wathsala Vithanage Reviewed-by: Honnappa Nagarahalli Reviewed-by: Ruifeng Wang --- .mailmap | 1 + lib/ring/rte_ring_c11_pvt.h | 6 ------ 2 files changed, 1 insertion(+), 6 deletions(-) diff --git a/.mailmap b/.mailmap index 4018f0fc47..367115d134 100644 --- a/.mailmap +++ b/.mailmap @@ -1430,6 +1430,7 @@ Walter Heymans Wang Sheng-Hui Wangyu (Eric) Waterman Cao +Wathsala Vithanage Weichun Chen Wei Dai Weifeng Li diff --git a/lib/ring/rte_ring_c11_pvt.h b/lib/ring/rte_ring_c11_pvt.h index f895950df4..eb59c61b6a 100644 --- a/lib/ring/rte_ring_c11_pvt.h +++ b/lib/ring/rte_ring_c11_pvt.h @@ -66,9 +66,6 @@ __rte_ring_move_prod_head(struct rte_ring *r, unsigned int is_sp, /* Reset n to the initial burst count */ n = max; - /* Ensure the head is read before tail */ - __atomic_thread_fence(__ATOMIC_ACQUIRE); - /* load-acquire synchronize with store-release of ht->tail * in update_tail. */ @@ -142,9 +139,6 @@ __rte_ring_move_cons_head(struct rte_ring *r, int is_sc, /* Restore n as it may change every loop */ n = max; - /* Ensure the head is read before tail */ - __atomic_thread_fence(__ATOMIC_ACQUIRE); - /* this load-acquire synchronize with store-release of ht->tail * in update_tail. */ -- 2.25.1