From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from lindbergh.monkeyblade.net (lindbergh.monkeyblade.net [23.128.96.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 9F701171A1 for ; Mon, 22 May 2023 19:17:12 +0000 (UTC) X-Greylist: delayed 4201 seconds by postgrey-1.37 at lindbergh.monkeyblade.net; Mon, 22 May 2023 12:17:10 PDT Received: from mail.8bytes.org (mail.8bytes.org [IPv6:2a01:238:42d9:3f00:e505:6202:4f0c:f051]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id EA8FDE9; Mon, 22 May 2023 12:17:09 -0700 (PDT) Received: from 8bytes.org (p200300c2773e310086ad4f9d2505dd0d.dip0.t-ipconnect.de [IPv6:2003:c2:773e:3100:86ad:4f9d:2505:dd0d]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange ECDHE (P-256) server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mail.8bytes.org (Postfix) with ESMTPSA id 0771D2434D7; Mon, 22 May 2023 18:10:03 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=8bytes.org; s=default; t=1684771803; bh=IEYacWChjS8pqW2eXYZUvSMLj48VE4JauxQLZBxYtqA=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=dsW1m+Y4pRxReMA3YAV1dR7xSpCrEFNRWPSoWZvvgL9y9t+B8nkXGdS5pIZgE/Mxc jDkmtQgdl3dVqv6n3e4yCwCoQwKfP4wgVU7uooQ8pyt47lwv0bvnKcPDbqciBPuGzz QflQuvzLHWoxNs4RdcEri8p72xuZLmU5YY/fJNWHmC0sEkQSGm+KOysLl+ctiUYkJ4 7Qlh+elGqPq5y9QZv4ABmp2fOJsDSjiUh+6IV6ASZ54RN9zWxU/tU36JULF7zRzETM EVBM6Dq0OgEW2aYEblrwJsY5LuCTfZP55UCddCCkbSfFJKvpE/vQhuL22KcZwPL64w mMOPCB+3NQIhg== Date: Mon, 22 May 2023 18:10:01 +0200 From: Joerg Roedel To: Niklas Schnelle Cc: Matthew Rosato , Will Deacon , Wenjia Zhang , Robin Murphy , Jason Gunthorpe , Gerd Bayer , Julian Ruess , Pierre Morel , Alexandra Winter , Heiko Carstens , Vasily Gorbik , Alexander Gordeev , Christian Borntraeger , Sven Schnelle , Suravee Suthikulpanit , Hector Martin , Sven Peter , Alyssa Rosenzweig , David Woodhouse , Lu Baolu , Andy Gross , Bjorn Andersson , Konrad Dybcio , Yong Wu , Matthias Brugger , AngeloGioacchino Del Regno , Gerald Schaefer , Orson Zhai , Baolin Wang , Chunyan Zhang , Chen-Yu Tsai , Jernej Skrabec , Samuel Holland , Thierry Reding , Krishna Reddy , Jonathan Hunter , Jonathan Corbet , linux-s390@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, iommu@lists.linux.dev, asahi@lists.linux.dev, linux-arm-kernel@lists.infradead.org, linux-arm-msm@vger.kernel.org, linux-mediatek@lists.infradead.org, linux-sunxi@lists.linux.dev, linux-tegra@vger.kernel.org, linux-doc@vger.kernel.org Subject: Re: [PATCH v9 6/6] iommu/dma: Make flush queue sizes and timeout driver configurable Message-ID: References: <20230310-dma_iommu-v9-0-65bb8edd2beb@linux.ibm.com> <20230310-dma_iommu-v9-6-65bb8edd2beb@linux.ibm.com> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20230310-dma_iommu-v9-6-65bb8edd2beb@linux.ibm.com> X-Spam-Status: No, score=-2.1 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,SPF_HELO_NONE,SPF_PASS, T_SCC_BODY_TEXT_LINE autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net On Mon, May 15, 2023 at 11:15:56AM +0200, Niklas Schnelle wrote: > In the s390 IOMMU driver a large fixed queue size and timeout is then > set together with single queue mode bringing its performance on s390 > paged memory guests on par with the previous s390 specific DMA API > implementation. Hmm, the right flush-queue size and timeout settings are more a function of the endpoint device and device driver than of the iommu driver, no? I think something like this could also help solving the recently reported scalability problems in the fq-code, if done right. Regards, Joerg