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 X-Spam-Level: X-Spam-Status: No, score=-9.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,NICE_REPLY_A,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 9FBCDC4363D for ; Wed, 7 Oct 2020 12:56:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 46435207EA for ; Wed, 7 Oct 2020 12:56:52 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=nvidia.com header.i=@nvidia.com header.b="GLRyM+FE" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728327AbgJGM4v (ORCPT ); Wed, 7 Oct 2020 08:56:51 -0400 Received: from hqnvemgate26.nvidia.com ([216.228.121.65]:1179 "EHLO hqnvemgate26.nvidia.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727253AbgJGM4v (ORCPT ); Wed, 7 Oct 2020 08:56:51 -0400 Received: from hqmail.nvidia.com (Not Verified[216.228.121.13]) by hqnvemgate26.nvidia.com (using TLS: TLSv1.2, AES256-SHA) id ; Wed, 07 Oct 2020 05:56:38 -0700 Received: from [172.27.0.178] (10.124.1.5) by HQMAIL107.nvidia.com (172.20.187.13) with Microsoft SMTP Server (TLS) id 15.0.1473.3; Wed, 7 Oct 2020 12:56:38 +0000 Subject: Re: reduce iSERT Max IO size To: Krishnamraju Eraparaju CC: Sagi Grimberg , , "Potnuri Bharat Teja" , Max Gurtovoy References: <20200922104424.GA18887@chelsio.com> <07e53835-8389-3e07-6976-505edbd94f2a@grimberg.me> <20201002171007.GA16636@chelsio.com> <4d0b1a3f-2980-c7ed-ef9a-0ed6a9c87a69@grimberg.me> <20201003033644.GA19516@chelsio.com> <4391e240-5d6d-fb59-e6fb-e7818d1d0bd2@nvidia.com> <20201007033619.GA11425@chelsio.com> From: Max Gurtovoy Message-ID: <1a034761-3723-3c70-8a44-25ef2cbf786e@nvidia.com> Date: Wed, 7 Oct 2020 15:56:26 +0300 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:68.0) Gecko/20100101 Thunderbird/68.12.1 MIME-Version: 1.0 In-Reply-To: <20201007033619.GA11425@chelsio.com> Content-Type: text/plain; charset="utf-8"; format=flowed Content-Transfer-Encoding: 7bit Content-Language: en-US X-Originating-IP: [10.124.1.5] X-ClientProxiedBy: HQMAIL111.nvidia.com (172.20.187.18) To HQMAIL107.nvidia.com (172.20.187.13) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=nvidia.com; s=n1; t=1602075398; bh=KGi2EGqHzZcHvsQFp3UhbKKhXpiDRmtuyhLH08FSzzU=; h=Subject:To:CC:References:From:Message-ID:Date:User-Agent: MIME-Version:In-Reply-To:Content-Type:Content-Transfer-Encoding: Content-Language:X-Originating-IP:X-ClientProxiedBy; b=GLRyM+FEm4UGEv2Xy+9a79BiwLvKv3ZSdHamad4J0R2h5dYh5jIVbsjJ39XNsySUQ PdCk9zCCvKIFC4+c7vT26uPOH56IB+HuZVAHM/gD8DWt7Iq7VlPjvz2LqZ8GQpviWx f0d5KtZM9f4svsI6McjYTlpHMHsqr8M7zNhPFYZvdgz0YS0GVULRe4P/AzVImDrIvo Cfb+uOQxWD3VbK19NA/D6HogvtYsymbH0Hq46dbZ5GfxI4bvGvN/wQOjE2zTZT6BRH bQQGD6Oj+82/JAWaDJwb70rZBNBVbJ3iseeITTu1g44AEUvdflK13eb8c/OkS+NkGX DCmWPxOWcCngA== Precedence: bulk List-ID: X-Mailing-List: linux-rdma@vger.kernel.org On 10/7/2020 6:36 AM, Krishnamraju Eraparaju wrote: > On Sunday, October 10/04/20, 2020 at 00:45:26 +0300, Max Gurtovoy wrote: >> On 10/3/2020 6:36 AM, Krishnamraju Eraparaju wrote: >>> On Friday, October 10/02/20, 2020 at 13:29:30 -0700, Sagi Grimberg wrote: >>>>> Hi Sagi & Max, >>>>> >>>>> Any update on this? >>>>> Please change the max IO size to 1MiB(256 pages). >>>> I think that the reason why this was changed to handle the worst case >>>> was in case there are different capabilities on the initiator and the >>>> target with respect to number of pages per MR. There is no handshake >>>> that aligns expectations. >>> But, the max pages per MR supported by most adapters is around 256 pages >>> only. >>> And I think only those iSER initiators, whose max pages per MR is 4096, >>> could send 16MiB sized IOs, am I correct? >> If the initiator can send 16MiB, we must make sure the target is >> capable to receive it. > I think max IO size, at iSER initiator, depends on > "max_fast_reg_page_list_len". > currently, below are the supported "max_fast_reg_page_list_len" of > various iwarp drivers: > > iw_cxgb4: 128 pages > Softiwarp: 256 pages > i40iw: 512 pages > qedr: couldn't find. > > For iwarp case, if 512 is the max pages supported by all iwarp drivers, > then provisioning a gigantic MR pool at target(to accommodate never used > 16MiB IO) wouldn't be a overkill? For RoCE/IB Mellanox HCAs we support 16MiB IO size and even more. We limited to 16MiB in iSER/iSERT. Sagi, what about adding a module parameter for this as we did in iSER initiator ? >>>> If we revert that it would restore the issue that you reported in the >>>> first place: >>>> >>>> -- >>>> IB/isert: allocate RW ctxs according to max IO size >>> I don't see the reported issue after reducing the IO size to 256 >>> pages(keeping all other changes of this patch intact). >>> That is, "attr.cap.max_rdma_ctxs" is now getting filled properly with >>> "rdma_rw_mr_factor()" related changes, I think. >>> >>> Before this change "attr.cap.max_rdma_ctxs" was hardcoded with >>> 128(ISCSI_DEF_XMIT_CMDS_MAX) pages, which is very low for single target >>> and muli-luns case. >>> >>> So reverting only ISCSI_ISER_MAX_SG_TABLESIZE macro to 256 doesn't cause the >>> reported issue. >>> >>> Thanks, >>> Krishnam Raju. >>>> Current iSER target code allocates MR pool budget based on queue size. >>>> Since there is no handshake between iSER initiator and target on max IO >>>> size, we'll set the iSER target to support upto 16MiB IO operations and >>>> allocate the correct number of RDMA ctxs according to the factor of MR's >>>> per IO operation. This would guaranty sufficient size of the MR pool for >>>> the required IO queue depth and IO size. >>>> >>>> Reported-by: Krishnamraju Eraparaju >>>> Tested-by: Krishnamraju Eraparaju >>>> Signed-off-by: Max Gurtovoy >>>> -- >>>> >>>>> Thanks, >>>>> Krishnam Raju. >>>>> On Wednesday, September 09/23/20, 2020 at 01:57:47 -0700, Sagi Grimberg wrote: >>>>>>> Hi, >>>>>>> >>>>>>> Please reduce the Max IO size to 1MiB(256 pages), at iSER Target. >>>>>>> The PBL memory consumption has increased significantly after increasing >>>>>>> the Max IO size to 16MiB(with commit:317000b926b07c). >>>>>>> Due to the large MR pool, the max no.of iSER connections(On one variant >>>>>>> of Chelsio cards) came down to 9, before it was 250. >>>>>>> NVMe-RDMA target also uses 1MiB max IO size. >>>>>> Max, remind me what was the point to support 16M? Did this resolve >>>>>> an issue?