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=-6.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=no 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 4F835C4338F for ; Tue, 10 Aug 2021 09:40:21 +0000 (UTC) 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 mail.kernel.org (Postfix) with ESMTPS id EC4286108C for ; Tue, 10 Aug 2021 09:40:20 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org EC4286108C Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=huawei.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:Content-Type: Content-Transfer-Encoding:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:Date:Message-ID:From: References:CC:To:Subject:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=kMrCsHc6qXT+P7JWmWOAHtrTTL7vNAHnPQVVjJw0vC0=; b=m+KaNTD3HQJ4D3wnQT8/W7TYs6 TWLkBdGnJC/gXk5Fclm/68R6ZPEwo29XtK01Lrgu7WkfL+9yoJSG6+XGIZu+dDqGcOjvlLhiU0K0a ENoWBiMujjJw5J9KX7J1NJUTi6N4Zp2dhKj8gWitaaW+kR3DlDbPCwwHZsyszg18+db53scYfu43p KC8dAVVqfWpJDVbPvAVHAxX5U+Pd+meWBFI+nNbnlBH7YqE+9ZCR7+GBxmZLSZHgj/zWpt5oVHvbr LV80CzKjzvQdbl6nDrcwTGRItM6Z/a61lb+OlY9XKRVwxbP2IhXdpaZ8m/vo8YFUb3bDj75sYMQ6P UE4bK/3w==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1mDOEq-003KrO-H0; Tue, 10 Aug 2021 09:40:00 +0000 Received: from frasgout.his.huawei.com ([185.176.79.56]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1mDOCO-003K1T-6p; Tue, 10 Aug 2021 09:37:30 +0000 Received: from fraeml740-chm.china.huawei.com (unknown [172.18.147.201]) by frasgout.his.huawei.com (SkyGuard) with ESMTP id 4GkSX12Jrkz6C9JD; Tue, 10 Aug 2021 17:36:49 +0800 (CST) Received: from lhreml724-chm.china.huawei.com (10.201.108.75) by fraeml740-chm.china.huawei.com (10.206.15.221) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2308.8; Tue, 10 Aug 2021 11:37:22 +0200 Received: from [10.47.80.4] (10.47.80.4) by lhreml724-chm.china.huawei.com (10.201.108.75) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2176.2; Tue, 10 Aug 2021 10:37:21 +0100 Subject: Re: [bug report] iommu_dma_unmap_sg() is very slow then running IO from remote numa node To: Ming Lei CC: Robin Murphy , , , , "Will Deacon" , References: <9c929985-4fcb-e65d-0265-34c820b770ea@huawei.com> <0adbe03b-ce26-e4d3-3425-d967bc436ef5@arm.com> <6ceab844-465f-3bf3-1809-5df1f1dbbc5c@huawei.com> From: John Garry Message-ID: Date: Tue, 10 Aug 2021 10:36:47 +0100 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: Content-Language: en-US X-Originating-IP: [10.47.80.4] X-ClientProxiedBy: lhreml712-chm.china.huawei.com (10.201.108.63) To lhreml724-chm.china.huawei.com (10.201.108.75) X-CFilter-Loop: Reflected X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210810_023728_497284_8FBA3828 X-CRM114-Status: GOOD ( 15.57 ) 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: , Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Sender: "Linux-nvme" Errors-To: linux-nvme-bounces+linux-nvme=archiver.kernel.org@lists.infradead.org On 28/07/2021 16:17, Ming Lei wrote: >>>> Have you tried turning off the IOMMU to ensure that this is really just >>>> an IOMMU problem? >>>> >>>> You can try setting CONFIG_ARM_SMMU_V3=n in the defconfig or passing >>>> cmdline param iommu.passthrough=1 to bypass the the SMMU (equivalent to >>>> disabling for kernel drivers). >>> Bypassing SMMU via iommu.passthrough=1 basically doesn't make a difference >>> on this issue. >> A ~90% throughput drop still seems to me to be too high to be a software >> issue. More so since I don't see similar on my system. And that throughput >> drop does not lead to a total CPU usage drop, from the fio log. >> >> Do you know if anyone has run memory benchmark tests on this board to find >> out NUMA effect? I think lmbench or stream could be used for this. > https://lore.kernel.org/lkml/YOhbc5C47IzC893B@T590/ Hi Ming, Out of curiosity, did you investigate this topic any further? And you also asked about my results earlier: On 22/07/2021 16:54, Ming Lei wrote: >> [ 52.035895] nvme 0000:81:00.0: Adding to iommu group 5 >> [ 52.047732] nvme nvme0: pci function 0000:81:00.0 >> [ 52.067216] nvme nvme0: 22/0/2 default/read/poll queues >> [ 52.087318] nvme0n1: p1 >> >> So I get these results: >> cpu0 335K >> cpu32 346K >> cpu64 300K >> cpu96 300K >> >> So still not massive changes. > In your last email, the results are the following with irq mode io_uring: > > cpu0 497K > cpu4 307K > cpu32 566K > cpu64 488K > cpu96 508K > > So looks you get much worse result with real io_polling? > Would the expectation be that at least I get the same performance with io_polling here? Anything else to try which you can suggest to investigate this lower performance? Thanks, John _______________________________________________ Linux-nvme mailing list Linux-nvme@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-nvme