From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id D1EFCC25B0E for ; Fri, 19 Aug 2022 07:58:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Type:MIME-Version: Message-ID:Date:Subject:CC:To:From:Reply-To:Content-Transfer-Encoding: Content-ID:Content-Description:Resent-Date:Resent-From:Resent-Sender: Resent-To:Resent-Cc:Resent-Message-ID:In-Reply-To:References:List-Owner; bh=XB9pn4kwbplcA/heEuxVXtJ+EYgX8oQ7hFuMQGQcbJw=; b=Xcak/9beo+vRj3QDyF9/ElcDkm JKREn7Pm1UBacOd5SutAYiba/gOVkzTOLIrDk1JqQWJtY8l8G+zU7lG3qqJ5iLIVKdDvztt3Gvhw8 QS7NvXHWGXMFhBeMyE4ICs6oc+b5QrMN18taEjaPfKaC0JaIi/K5pImV9tGLUhiqq3RMTr+2nOXYY SFhYUvSye8DQ6OaK/ijef56x+xe5IoHWPnDUxO9opTTrj0EKKsOkBZosBPLVBUCusFJtlsN6OnW+5 Q560qTn/D2yDQdS7AXsS+XoSAp2Y/zFlZHNfg15lWqHV5SH1GHRQk9/F6yiMmY9XjXkI1ge1Z1DVN kOF003TQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1oOwtu-003hrc-S6; Fri, 19 Aug 2022 07:58:42 +0000 Received: from szxga02-in.huawei.com ([45.249.212.188]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1oOwtr-003hn5-Rl for linux-nvme@lists.infradead.org; Fri, 19 Aug 2022 07:58:41 +0000 Received: from canpemm500002.china.huawei.com (unknown [172.30.72.55]) by szxga02-in.huawei.com (SkyGuard) with ESMTP id 4M8DZH56fkzlW7S; Fri, 19 Aug 2022 15:55:19 +0800 (CST) Received: from huawei.com (10.29.88.127) by canpemm500002.china.huawei.com (7.192.104.244) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.24; Fri, 19 Aug 2022 15:58:26 +0800 From: Chao Leng To: CC: , , , Subject: [PATCH] nvme-rdma: set ack timeout of RoCE to 262ms Date: Fri, 19 Aug 2022 15:58:25 +0800 Message-ID: <20220819075825.21231-1-lengchao@huawei.com> X-Mailer: git-send-email 2.16.4 MIME-Version: 1.0 Content-Type: text/plain X-Originating-IP: [10.29.88.127] X-ClientProxiedBy: dggems702-chm.china.huawei.com (10.3.19.179) To canpemm500002.china.huawei.com (7.192.104.244) X-CFilter-Loop: Reflected X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20220819_005840_129089_5E5DF135 X-CRM114-Status: UNSURE ( 8.87 ) X-CRM114-Notice: Please train this message. X-BeenThere: linux-nvme@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "Linux-nvme" Errors-To: linux-nvme-bounces+linux-nvme=archiver.kernel.org@lists.infradead.org Now the ack timeout of RoCE is 2 second(2^(18+1)*4us=2 second). In the case of low concurrency, if some packets lost due to network abnormal such as network rerouting, Optical fiber signal interference, etc, it will wait 2 second to try retransmitting the lost packets. As a result, the I/O latency is greater than 2 seconds. The I/O latency is so long for real-time transaction service. Indeed we do not have to wait so long time to make sure that packets are lost. Setting the ack timeout to 262ms(2^(15+1)*4us=262ms) is sufficient. Signed-off-by: Chao Leng --- drivers/nvme/host/rdma.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/nvme/host/rdma.c b/drivers/nvme/host/rdma.c index 7d01fb770284..2dbb1b21acc8 100644 --- a/drivers/nvme/host/rdma.c +++ b/drivers/nvme/host/rdma.c @@ -602,6 +602,8 @@ static int nvme_rdma_alloc_queue(struct nvme_rdma_ctrl *ctrl, ret = PTR_ERR(queue->cm_id); goto out_destroy_mutex; } + /* set ack timeout to 262ms(2^(15+1)*4us=262ms) */ + rdma_set_ack_timeout(queue->cm_id, 15); if (ctrl->ctrl.opts->mask & NVMF_OPT_HOST_TRADDR) src_addr = (struct sockaddr *)&ctrl->src_addr; -- 2.16.4