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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id C0A54C4332F for ; Wed, 23 Nov 2022 02:13:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235093AbiKWCNw (ORCPT ); Tue, 22 Nov 2022 21:13:52 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33868 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233625AbiKWCNw (ORCPT ); Tue, 22 Nov 2022 21:13:52 -0500 Received: from szxga01-in.huawei.com (szxga01-in.huawei.com [45.249.212.187]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 88033B9B9E for ; Tue, 22 Nov 2022 18:13:51 -0800 (PST) Received: from canpemm500002.china.huawei.com (unknown [172.30.72.57]) by szxga01-in.huawei.com (SkyGuard) with ESMTP id 4NH4RL64zxzmW2r; Wed, 23 Nov 2022 10:13:18 +0800 (CST) Received: from [10.169.59.127] (10.169.59.127) 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 15.1.2375.31; Wed, 23 Nov 2022 10:13:49 +0800 Subject: Re: [for-next PATCH] infiniband:cma: add a parameter for the packet lifetime To: Jason Gunthorpe CC: , References: <20221122090206.865-1-lengchao@huawei.com> From: Chao Leng Message-ID: Date: Wed, 23 Nov 2022 10:13:48 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:68.0) Gecko/20100101 Thunderbird/68.12.1 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset="utf-8"; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-Originating-IP: [10.169.59.127] X-ClientProxiedBy: dggems701-chm.china.huawei.com (10.3.19.178) To canpemm500002.china.huawei.com (7.192.104.244) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-rdma@vger.kernel.org On 2022/11/22 22:08, Jason Gunthorpe wrote: > On Tue, Nov 22, 2022 at 05:02:06PM +0800, Chao Leng wrote: >> Now the default packet lifetime(CMA_IBOE_PACKET_LIFETIME) is 18. >> That means the minimum ack timeout is 2 seconds(2^(18+1)*4us=2.097seconds). >> The packet lifetime means the maximum transmission time of packets >> on the network, the maximum transmission time of packets is closely >> related to the network. 2 seconds is too long for simple lossless networks. >> The packet lifetime should allow the user to adjust according to the >> network situation. >> So add a parameter for the packet lifetime. >> >> Signed-off-by: Chao Leng >> --- >> drivers/infiniband/core/cma.c | 6 +++++- >> 1 file changed, 5 insertions(+), 1 deletion(-) >> >> diff --git a/drivers/infiniband/core/cma.c b/drivers/infiniband/core/cma.c >> index cc2222b85c88..8e2ff5d610e3 100644 >> --- a/drivers/infiniband/core/cma.c >> +++ b/drivers/infiniband/core/cma.c >> @@ -50,6 +50,10 @@ MODULE_LICENSE("Dual BSD/GPL"); >> #define CMA_IBOE_PACKET_LIFETIME 18 >> #define CMA_PREFERRED_ROCE_GID_TYPE IB_GID_TYPE_ROCE_UDP_ENCAP >> >> +static unsigned char cma_packet_lifetime = CMA_IBOE_PACKET_LIFETIME; >> +module_param_named(packet_lifetime, cma_packet_lifetime, byte, 0644); >> +MODULE_PARM_DESC(packet_lifetime, "max transmission time of the packet"); > > No new module parameters > > Maybe something in netlink would be appropriate, I'm not sure how > best to deal with this. > > Really, the entire retransmit strategy in CM is not suitable for > ethernet networks, this is just one symptom. What do you think to change the CMA_IBOE_PACKET_LIFETIME to 16. The maximum transmission time of packets will be about 500+ms, I think this is long enough for RoCE networks. 2 seconds is too long to my honest.