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 smtp2.osuosl.org (smtp2.osuosl.org [140.211.166.133]) (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 82B72C433EF for ; Mon, 18 Apr 2022 11:44:52 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by smtp2.osuosl.org (Postfix) with ESMTP id 2DA4941012; Mon, 18 Apr 2022 11:44:52 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from smtp2.osuosl.org ([127.0.0.1]) by localhost (smtp2.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id 7xJtgjdrmVpB; Mon, 18 Apr 2022 11:44:51 +0000 (UTC) Received: from lists.linuxfoundation.org (lf-lists.osuosl.org [IPv6:2605:bc80:3010:104::8cd3:938]) by smtp2.osuosl.org (Postfix) with ESMTPS id 13BCF40579; Mon, 18 Apr 2022 11:44:51 +0000 (UTC) Received: from lf-lists.osuosl.org (localhost [127.0.0.1]) by lists.linuxfoundation.org (Postfix) with ESMTP id E39BDC002F; Mon, 18 Apr 2022 11:44:50 +0000 (UTC) Received: from smtp2.osuosl.org (smtp2.osuosl.org [140.211.166.133]) by lists.linuxfoundation.org (Postfix) with ESMTP id C29EDC002C for ; Mon, 18 Apr 2022 11:44:49 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by smtp2.osuosl.org (Postfix) with ESMTP id A074040579 for ; Mon, 18 Apr 2022 11:44:49 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from smtp2.osuosl.org ([127.0.0.1]) by localhost (smtp2.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id ekk7YIk_itnI for ; Mon, 18 Apr 2022 11:44:49 +0000 (UTC) X-Greylist: domain auto-whitelisted by SQLgrey-1.8.0 Received: from mga06.intel.com (mga06b.intel.com [134.134.136.31]) by smtp2.osuosl.org (Postfix) with ESMTPS id DEE0740297 for ; Mon, 18 Apr 2022 11:44:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1650282288; x=1681818288; h=message-id:date:mime-version:cc:to:references:from: subject:in-reply-to:content-transfer-encoding; bh=ed9XtiWvuduH3tePyFDVZz4+lZ73C5IN2pEFYdP+YKI=; b=aw2Mjak+93FclCcIlf9i+OqhUpfmbIf6LjOV46n7HlmdtYKeBgR7Fr9r 60LN4nRizwPhYgbSBZgwSq+bx2m/aVs6VmxVAMsTWxP5h9GGNxNbpz5ks 3nitAuArXAwhmituSAobqgS1Q/2rtdlcMEwe2Yfql+5AU9w965a4QP0/M BJtb5N1HExkEUgpFt40pOFrtME4VQen4oO/A4/Qx1R/1Mt5AyuPwt7zTe Gwmec3B0+fU8CIlrVNjfVNdliPD7LDHkI1X4pyVgQYBxBibvx8t1hHqO9 o+0Vf2c1obq9oipg7KwiwS+c+uzVtDgWxC0l/1TwFttXA2TI3eF8I625v Q==; X-IronPort-AV: E=McAfee;i="6400,9594,10320"; a="323944345" X-IronPort-AV: E=Sophos;i="5.90,269,1643702400"; d="scan'208";a="323944345" Received: from orsmga008.jf.intel.com ([10.7.209.65]) by orsmga104.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 18 Apr 2022 04:44:48 -0700 X-IronPort-AV: E=Sophos;i="5.90,269,1643702400"; d="scan'208";a="575541874" Received: from blu2-mobl3.ccr.corp.intel.com (HELO [10.254.208.231]) ([10.254.208.231]) by orsmga008-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 18 Apr 2022 04:44:46 -0700 Message-ID: <46f51f30-28e9-4b91-acd5-1df43c1428d6@linux.intel.com> Date: Mon, 18 Apr 2022 19:44:44 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:91.0) Gecko/20100101 Thunderbird/91.8.0 Content-Language: en-US To: "Tian, Kevin" , "Pan, Jacob jun" , "Raj, Ashok" , "Liu, Yi L" References: <20220416123049.879969-1-baolu.lu@linux.intel.com> <20220416123049.879969-4-baolu.lu@linux.intel.com> From: Lu Baolu Subject: Re: [PATCH 3/3] iommu/vt-d: Size Page Request Queue to avoid overflow condition In-Reply-To: Cc: "iommu@lists.linux-foundation.org" , "linux-kernel@vger.kernel.org" X-BeenThere: iommu@lists.linux-foundation.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: Development issues for Linux IOMMU support List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Errors-To: iommu-bounces@lists.linux-foundation.org Sender: "iommu" On 2022/4/18 15:00, Tian, Kevin wrote: >> From: Lu Baolu >> Sent: Saturday, April 16, 2022 8:31 PM >> >> PRQ overflow may cause I/O throughput congestion, resulting in unnecessary >> degradation of IO performance. Appropriately increasing the length of PRQ >> can greatly reduce the occurrence of PRQ overflow. The count of maximum >> page requests that can be generated in parallel by a PCIe device is >> statically defined in the Outstanding Page Request Capacity field of the >> PCIe ATS configure space. >> >> The new lenght of PRQ is calculated by summing up the value of Outstanding >> Page Request Capacity register across all devices where Page Requests are >> supported on the real PR-capable platfrom (Intel Sapphire Rapids). The >> result is round to the nearest higher power of 2. > The actual requirement is usage and platform specific. What about > doubling the default size and also provide an option for admin to > tune? I also have this in my list to provide an opt-in interface for user. But I don't want to include it in this series as this is only for small tuning. The opt-in interface looks more like a new feature. :-) Best regards, baolu _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu