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Thu, 2 Jul 2020 10:26:18 +0900 (KST) Received: from [10.113.221.102] (unknown [10.113.221.102]) by epsmtip2.samsung.com (KnoxPortal) with ESMTPA id 20200702012618epsmtip2dc5d3d6ff220c54a553be1ac4db67d1a~dyx9IzkTV2710427104epsmtip2G; Thu, 2 Jul 2020 01:26:18 +0000 (GMT) Subject: Re: [PATCH v4 16/37] PM / devfreq: tegra20: Adjust clocks conversion ratio and polling interval To: Dmitry Osipenko , Thierry Reding , Jonathan Hunter , Georgi Djakov , Rob Herring , Michael Turquette , Stephen Boyd , Peter De Schrijver , MyungJoo Ham , Kyungmin Park , Mikko Perttunen Cc: =?UTF-8?B?QXJ0dXIgxZp3aWdvxYQ=?= , linux-tegra@vger.kernel.org, linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org, devicetree@vger.kernel.org From: Chanwoo Choi Organization: Samsung Electronics Message-ID: Date: Thu, 2 Jul 2020 10:37:34 +0900 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:59.0) Gecko/20100101 Thunderbird/59.0 MIME-Version: 1.0 In-Reply-To: <20200609131404.17523-17-digetx@gmail.com> Content-Language: en-US Content-Transfer-Encoding: 7bit X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFrrPJsWRmVeSWpSXmKPExsWy7bCmru5u879xBn82s1vcn9fKaPHu01NW i/lHzrFarP74mNHiytf3bBbT925is2iZtYjF4mzTG3aLy7vmsFl87j3CaNH5ZRabxcVTrha3 G1ewWUxaO5XRonXvEXaLf9c2slj83DWPxUHQ4/2NVnaPnbPusntcOveH2WPTqk42jzvX9rB5 3O8+zuTR2/yOzaNvyypGj8+b5AI4o7JtMlITU1KLFFLzkvNTMvPSbZW8g+Od403NDAx1DS0t zJUU8hJzU22VXHwCdN0yc4B+UVIoS8wpBQoFJBYXK+nb2RTll5akKmTkF5fYKqUWpOQUWBbo FSfmFpfmpesl5+daGRoYGJkCFSZkZ7xasYi1YJNwxb6jV9gaGF/ydzFyckgImEh823ecvYuR i0NIYAejxObml1DOJ0aJ5mnXWEGqhAQ+M0rcXlkJ13FpGzNE0S5Gibn3r0J1vGeUODd9GztI lbBAlsT9e/PYQBIiAkeYJVZ3HmcEcZgFLjNKnG37wgZSxSagJbH/xQ0wm19AUeLqj8eMIDav gJ3E72cHwHazCKhItO9ewgxiiwqESZzc1gJVIyhxcuYTFhCbU8Bc4vfb6WBzmAXEJW49mc8E YctLbH87B+xWCYF2TonbBy+yQTzhIrH34y5GCFtY4tXxLewQtpTEy/42KLtaYuXJI2wQzR2M Elv2X2CFSBhL7F86GWgDB9AGTYn1u/QhwooSO3/PZYRYzCfx7msPK0iJhACvREebEESJssTl B3eZIGxJicXtnWwTGJVmIXlnFpIXZiF5YRbCsgWMLKsYxVILinPTU4sNC4yQ43sTIzila5nt YJz09oPeIUYmDsZDjBIczEoivKcNfsUJ8aYkVlalFuXHF5XmpBYfYjQFBvBEZinR5HxgVskr iTc0NTI2NrYwMTQzNTRUEudVk7kQJySQnliSmp2aWpBaBNPHxMEp1cBkxmHzeoXVOa57lW+t 7YSMPH9wcfH+cmGrLedOe32N94jh/eyLD5wmp9j7OjyTeNBldTijwdNfM00yu7FSsqXEdnlu Rf3ssJcbdMPWbj+wNPl0z+GzM4SUma7nPo491bAm49Bk9frI51s/FdslWh/4WxO5psU+5Qnv sRWbuspvsYjPqv+7Lblu+rmWG0wPTX3n2DKyxatIlr5k3pk3qWnyYaZlkbNjm30NbiQb7n4n cZlNgrd2YURtyf01wo/Crzz6tbOKXWrO+oPd308Zmejr+XI/7evtXPo189E7oeRpegs7XS+0 NCYHZfvtD3u2QO7NLFkJi83aq0/L8d/WXVt56nhNF2O0pPT3BSael5VYijMSDbWYi4oTAT0q dw5yBAAA X-Brightmail-Tracker: H4sIAAAAAAAAA02Re0hTYRjG/c45np1Jw+NW7bMkc1niQtMS/IiQIKVjRESZQYa52sH7lB0v aRFlmc0wpfK2RE1KbZbVSptLK5xLdChObURODGZSllnquqld5gj87/fyPL/nn5fChb3EGipR kcEqFbIUCelGtBok3gH60MXYoNHuADRWnQ/Q55l3rqimq98VNX21ATRsnyZReYeWRBfUdQTq y/vEQ0P6KhLNFnUBpJpTk8jcG4FGzjWS6Oq9UoDyO7p46LflIYF+6quJnR7M9Ot8HtOmHuUx g/0LOKPVqEjGamknmbHL3RhTdP4zyVx5rAHMrHbdfv4Rtx1yNiUxi1VuCYtzS5hsrHNN14pO PjMOk2fBB/dCwKcgHQK/DbbihcCNEtI6AG0VE5gz8IRlZuO/gPrHImgwcM7OFID117SEoyOi k6DmTR/pCFbSL3GoNZkwx4HTQwDqVHbSqbQCWGoeXlJIWgqfv39NOtid9oGvftiAgwV0GJyf eOHqYIL2hQVPb+EOXkVHw7ZbNszZ8YA9leNLO3w6FM5PlS/t4LQfXKgexJ0shm/GazAne8Mn U1V4CRCpl+nqZYp6maJeptQCQgM82XQuNT6VC07fqmCzAzlZKpepiA88kZaqBUvvlkp1oF3z JbATYBToBJDCJSsFpqBfsUKBXJaTyyrTjikzU1iuE6ylCIlYYFffjBXS8bIMNpll01nl/xSj +GvOYjEbinX78nKbb3SMiMey9FFppXd8I5+YCgij5Xf0vrnvD6hsmfssJ6n0uPR8oD2ndMXI YgnZ5OeyaNlYNGctmLTP1+6p/CiShgsWvZIMtxvkXR+/nTZOb25Ozjpn+8E/wD1I/rThS8wC FyPu673zUO7TdgGGHb/fvJY2BVvydhfXRKjqDyUkHNSHZ2t1LcZj8WfsWNPdUOup8fWqDK8X u8z9faNxVfmKvRWMy4eNm2K7J07F1eYePXH4VZQ5YPvENjTQYi17e70ncJt/jkElj/TsnSsn H+nC50cvzvjjLe94oUCzOUboFa06cprzoqxRxX/g6hDz9k2ZMy4NyeKLEoJLkAVLcSUn+wuK LJ35XQMAAA== X-CMS-MailID: 20200702012618epcas1p22d53f5f254949f59ff091b8035ec360d X-Msg-Generator: CA Content-Type: text/plain; charset="utf-8" X-Sendblock-Type: SVC_REQ_APPROVE CMS-TYPE: 101P DLP-Filter: Pass X-CFilter-Loop: Reflected X-CMS-RootMailID: 20200609131504epcas1p1069393852a0d53f5ea31ded7aff34a93 References: <20200609131404.17523-1-digetx@gmail.com> <20200609131404.17523-17-digetx@gmail.com> Sender: devicetree-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: devicetree@vger.kernel.org On 6/9/20 10:13 PM, Dmitry Osipenko wrote: > The current conversion ratio results in a higher frequency than needed, > that is not very actual now since the Display Controller driver got > support for memory bandwidth management and hence memory frequency can > go lower now without bad consequences. Since memory freq now goes to a > lower rates, the responsiveness of interactive applications become worse > due to a quite high polling interval value that is currently set to 500ms. > Changing polling interval to 30ms results in a good responsiveness of the > system. > > Signed-off-by: Dmitry Osipenko > --- > drivers/devfreq/tegra20-devfreq.c | 14 +++++--------- > 1 file changed, 5 insertions(+), 9 deletions(-) > > diff --git a/drivers/devfreq/tegra20-devfreq.c b/drivers/devfreq/tegra20-devfreq.c > index 249d0dc44f6c..7cdea4ba38f7 100644 > --- a/drivers/devfreq/tegra20-devfreq.c > +++ b/drivers/devfreq/tegra20-devfreq.c > @@ -79,16 +79,12 @@ static int tegra_devfreq_get_dev_status(struct device *dev, > > /* > * EMC_COUNT returns number of memory events, that number is lower > - * than the number of clocks. Conversion ratio of 1/8 results in a > - * bit higher bandwidth than actually needed, it is good enough for > - * the time being because drivers don't support requesting minimum > - * needed memory bandwidth yet. > - * > - * TODO: adjust the ratio value once relevant drivers will support > - * memory bandwidth management. > + * than the number of total EMC clocks over the sampling period. > + * The clocks number is converted to maximum possible number of > + * memory events using the ratio of 1/4. > */ > stat->busy_time = readl_relaxed(tegra->regs + MC_STAT_EMC_COUNT); > - stat->total_time = readl_relaxed(tegra->regs + MC_STAT_EMC_CLOCKS) / 8; > + stat->total_time = readl_relaxed(tegra->regs + MC_STAT_EMC_CLOCKS) / 4; > stat->current_frequency = clk_get_rate(tegra->emc_clock); > > writel_relaxed(EMC_GATHER_CLEAR, tegra->regs + MC_STAT_CONTROL); > @@ -98,7 +94,7 @@ static int tegra_devfreq_get_dev_status(struct device *dev, > } > > static struct devfreq_dev_profile tegra_devfreq_profile = { > - .polling_ms = 500, > + .polling_ms = 30, > .target = tegra_devfreq_target, > .get_dev_status = tegra_devfreq_get_dev_status, > }; > Ackded-by: Chanwoo Choi -- Best Regards, Chanwoo Choi Samsung Electronics