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 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 smtp.lore.kernel.org (Postfix) with ESMTPS id 4A48DE936EB for ; Wed, 4 Oct 2023 22:00:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Message-ID:Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=727VwNoaDSwa4BQiJdZHlOEPWbzXE9TnU581Y9IJXBg=; b=FYPs0U/FHgWsbJ /YOIEmD8pE6CX1md8fF9VMAb25yuIkb1Hb3bmUl+niQ1V0lwvbP6BVUKwhVqYXdnfVexegXilBsXu TeM/3kUzxsF7M2ya3bukmbMLvuCtyCOsk4ok6Q7m4DfwwAc9yJ4twRRlYn1P7HBiB/WXNJvV/EmpF mdGlQtuHV1LpJa/nqFFqJJ0ZNRj+uIuFZ0ZG+hkKIfmu2sm4HXQYCj3dM2MsdJTZB4Z+QiGSeWwR4 qdWTwqG/bgC+EBgbLoyrhSPWct++VkavuO11EGh69stWpSJeDyTLLnioZmzIcKkX6CFGD+ssqhesX YC5+lAe79KU6swH6g6Mg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1qo9uQ-000xc9-0z; Wed, 04 Oct 2023 21:59:58 +0000 Received: from dfw.source.kernel.org ([2604:1380:4641:c500::1]) by bombadil.infradead.org with esmtps (Exim 4.96 #2 (Red Hat Linux)) id 1qo9uM-000xbd-0Y for linux-arm-kernel@lists.infradead.org; Wed, 04 Oct 2023 21:59:55 +0000 Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by dfw.source.kernel.org (Postfix) with ESMTP id 351A461782; Wed, 4 Oct 2023 21:59:53 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0ACD8C433C8; Wed, 4 Oct 2023 21:59:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1696456792; bh=h1wuJu7EQsw0ISUx0TDepOY/LS54P4l5en5rkpEd2fY=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=IQXXKp3mHSs7C3RpBvqk6NjjA3omclpdvfBr+th98AGd/jJHwr+SNYt3DrQA/tTC6 CGVXbkPAeLNP+ogRrvru18i0GSibBl+w7HXMap5DQDuOrYmLdw+Tx1W6/MbCpIrsYq uQ3amhujSUY0KGp2MM38dxsXREQ33YXtIE15pnkYiOSaXPIiIUmxtBEpzyfZ9vgDDo bI7OyMePLY5CWCjr27kEoifclTlu1G2sjnuJ22oAvnoWRy9zz4MvD4Uf4V77e1j84o PZj8x033qUbHukwEnp7u6/RJOHhxm8BSYTwVY5olkQb+SrKjjXJGu8bwuLwx25JHMi kQ8hdjMEwCLSQ== Date: Wed, 4 Oct 2023 14:59:51 -0700 From: Jakub Kicinski To: Shenwei Wang Cc: "David S. Miller" , Eric Dumazet , Paolo Abeni , Shawn Guo , Sascha Hauer , Maxime Coquelin , Alexandre Torgue , Jose Abreu , Pengutronix Kernel Team , Fabio Estevam , NXP Linux Team , netdev@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-stm32@st-md-mailman.stormreply.com, imx@lists.linux.dev, Mario Castaneda Subject: Re: [PATCH net] net: stmmac: dwmac-imx: request high frequency mode Message-ID: <20231004145951.570a8ce4@kernel.org> In-Reply-To: <20231004195442.414766-1-shenwei.wang@nxp.com> References: <20231004195442.414766-1-shenwei.wang@nxp.com> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20231004_145954_275134_9972F801 X-CRM114-Status: GOOD ( 16.13 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Wed, 4 Oct 2023 14:54:42 -0500 Shenwei Wang wrote: > Some i.MX SoCs like the i.mx8mq support adjusting the frequency of the > DDR, AHB, and AXI buses based on system loading. If the dwmac interface > in the driver does not request a HIGH frequency, it can significantly > degrade performance when the system switches to a lower frequency to > conserve power. > > For example, on an i.MX8MQ EVK board, the throughput dropped to around > 100Mbit/s on a 1Gbit connection: > > [ ID] Interval Transfer Bitrate > [ 5] 0.00-10.00 sec 117 MBytes 97.9 Mbits/sec > > However, throughput can return to expected levels after its driver requests > the high frequency mode. Requesting high frequency in the dwmac driver is > essential to maintain full throughput when the i.MX SoC adjusts bus speeds > for power savings. Oh, another one in one day :S Although this one feels much more like a bug that escaped testing because testing didn't use power saving? In any case, do you happen to have a user report you can mention here? Quoting stable rules: | Serious issues as reported by a user of a distribution kernel may also | be considered if they fix a notable performance or interactivity | issue. As these fixes are not as obvious and have a higher risk of a | subtle regression they should only be submitted by a distribution | kernel maintainer and include an addendum linking to a bugzilla entry | if it exists and additional information on the user-visible impact. And a Fixes tag would be good, please add. -- pw-bot: cr _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel