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Wed, 3 Apr 2024 01:42:08 +0000 (GMT) Received: from epsmgms1p1new.samsung.com (unknown [182.195.42.41]) by epsmtrp1.samsung.com (KnoxPortal) with ESMTP id 20240403014208epsmtrp1bb1f4079774e3a65d555c7cbbf6c87a1~CoaKWmwnH0428504285epsmtrp1d; Wed, 3 Apr 2024 01:42:08 +0000 (GMT) X-AuditID: b6c32a45-a89fa700000025c9-37-660cb3f0583e Received: from epsmtip1.samsung.com ( [182.195.34.30]) by epsmgms1p1new.samsung.com (Symantec Messaging Gateway) with SMTP id 77.06.08924.FE3BC066; Wed, 3 Apr 2024 10:42:07 +0900 (KST) Received: from KORCO045595.samsungds.net (unknown [10.229.38.76]) by epsmtip1.samsung.com (KnoxPortal) with ESMTPA id 20240403014207epsmtip15df1b7d5d829712f2cd93eacc3465cac~CoaKMMZDy1272212722epsmtip1A; Wed, 3 Apr 2024 01:42:07 +0000 (GMT) Date: Wed, 3 Apr 2024 10:42:07 +0900 From: Bongkyu Kim To: John Stultz Cc: peterz@infradead.org, mingo@redhat.com, will@kernel.org, longman@redhat.com, boqun.feng@gmail.com, linux-kernel@vger.kernel.org, gregkh@linuxfoundation.org, bongkyu7.kim@samsung.com Subject: Re: [PATCH v2 0/2] Make reader optimistic spinning optional Message-ID: <20240403014207.GA499@KORCO045595.samsungds.net> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 In-Reply-To: X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFlrHJsWRmVeSWpSXmKPExsWy7bCmue6HzTxpBtMXiVi8bnzJZLFmSyOT RfPi9WwWf05sZLO4vGsOm8XpYydYLC4dWMBkcbz3AJNFyx1TB06PnbPusnss2FTqsXmFlsem VZ1sHvvnrmH3eL/vKptH35ZVjB6fN8kFcERl22SkJqakFimk5iXnp2TmpdsqeQfHO8ebmhkY 6hpaWpgrKeQl5qbaKrn4BOi6ZeYAHaekUJaYUwoUCkgsLlbSt7Mpyi8tSVXIyC8usVVKLUjJ KTAv0CtOzC0uzUvXy0stsTI0MDAyBSpMyM749GQdY8F8uYol154yNTBOF+1i5OSQEDCReHB7 MlsXIxeHkMAORonV/3YxQTifGCVa751mhHC+MUrcaTzADtOy799OqKq9jBL3/71igavaeGUq cxcjBweLgIrE5yNaIA1sAjoS/1fPYAKxRYDCD+f+BNvHDNJ84cMlZpCEsICLRNv39YwgNq+A jcSEcxOhbEGJkzOfsIDYnAKBEo1334I1Swgs5ZBYuLKdCeIkF4ljv1qhzhOWeHV8C5QtJfGy vw3KLpaY+BLkOJDmBkaJptfbWSASxhKznrWDbWMWyJCY+fY/E8gHEgLKEkdusUCE+SQ6Dv9l hwjzSnS0CUF0qknsft7KCmHLSBw8uxbqHA+JawcnQ0PoEpNE7+9r7BMY5WYh+WcWkm2zgMYy C2hKrN+lDxGWl2jeOpsZIiwtsfwfB5KKBYxsqxjFUguKc9NTi40KDOGxnZyfu4kRnHC1XHcw Tn77Qe8QIxMH4yFGCQ5mJRHen96caUK8KYmVValF+fFFpTmpxYcYTYHxNJFZSjQ5H5jy80ri DU0sDUzMzAzNjUwNzJXEee+1zk0REkhPLEnNTk0tSC2C6WPi4JRqYAqI99xlr3RV6vVtd/7/ el9iEhy/d28RNfh0b33tZlf1diGrr4Yu6ff2cWaJ/2SSO2P1Y7OOxOutHw98TDGz40xq+Lvk dXri12d3dhw6+3tvpDxTONeestcG+5aWrDlf/+Q3W5ubxuyNtRf5rZ8JdtfxbP671U7F/qzJ g3WlZlPS5I9d2D+7cfrLd1xGJa09rgyPWKUYS8NEqtruRbaeN904Nypjol3tku8TObepfRRe fH7Z5oq578v89I8vX+64Zam46sXCEyXvbV+/q1Ddnn8t3++dqDFT+N26BWfenziWvfc0+1XP W7PzuUUeqq4MmrI+hKVAQatNjCVpRm5BZID1omnHtwiyKFkUC6blr1ViKc5INNRiLipOBAAN 9jtNQQQAAA== X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFmpgkeLIzCtJLcpLzFFi42LZdlhJTvf9Zp40g/3brC1eN75kslizpZHJ onnxejaLPyc2sllc3jWHzeL0sRMsFpcOLGCyON57gMmi5Y6pA6fHzll32T0WbCr12LxCy2PT qk42j/1z17B7vN93lc2jb8sqRo/Pm+QCOKK4bFJSczLLUov07RK4Mk7cPMxUcFC64ubmPtYG xqtCXYycHBICJhL7/u1k6mLk4hAS2M0o8ayniQkiISNx6N9aKFtY4n7LEVaIoi+MEpcX/mXs YuTgYBFQkfh8RAukhk1AR+L/6hlg9SJA4Ydzf7KB1DML7GeU6L6yghkkISzgItH2fT0jiM0r YCMx4dxERoihl5gkDkw4zw6REJQ4OfMJC4jNLKAu8WfeJWaQZcwC0hLL/3FAhOUlmrfOBpvJ KRAo0Xj3LdsERsFZSLpnIemehdA9C0n3AkaWVYySqQXFuem5xYYFhnmp5XrFibnFpXnpesn5 uZsYwZGkpbmDcfuqD3qHGJk4GA8xSnAwK4nw/vTmTBPiTUmsrEotyo8vKs1JLT7EKM3BoiTO K/6iN0VIID2xJDU7NbUgtQgmy8TBKdXANH319QvGa98uTQjKaf116+u7Py9etUtbl05f+mJl bKKT330j2+o71wTS7ux7MuW+1fFPHD/fykx5HbqrKCZ2fYml69vOy3kbl8jJbZVe+M42yk6M z1TsfvytoxMX8LDs+v9e/ePfRxl3d65+6FtWnf/Z+YnNpI/fJsR8N7Fg8l3a2pf1QED4uQgb z+GbBk6SE+ZWrviZon2waM5Sq6cH2N8IvwkxzBE+UjF54oHCGzrKJSWb73sem2Z4Lfdu6JVI /hSvZe6PJAr9rrovnPzsM3P4V/Uz7JxGk5c9fvS0+rKve9IrUZW+nJPzlBoOzTXz81VIy1HR N/b4cFnSXPBzeONJi2VMro+DuD6WXd21/ZISS3FGoqEWc1FxIgCTxerAEwMAAA== X-CMS-MailID: 20240403014208epcas2p4c27e6414361437cbe5a6ba6673d7058b X-Msg-Generator: CA Content-Type: multipart/mixed; boundary="----9D_2.EQ5cGIhcMb2E9QR8GFUB51-NQQYsO-rsNzGreYF.8HD=_b7a51_" X-Sendblock-Type: AUTO_CONFIDENTIAL CMS-TYPE: 102P DLP-Filter: Pass X-CFilter-Loop: Reflected X-CMS-RootMailID: 20230901010734epcas2p4aadced02d68d3db407fda23de34601d2 References: <20230901010704.18493-1-bongkyu7.kim@samsung.com> <20240403012132.GA460@KORCO045595.samsungds.net> ------9D_2.EQ5cGIhcMb2E9QR8GFUB51-NQQYsO-rsNzGreYF.8HD=_b7a51_ Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 8bit Content-Disposition: inline On Tue, Apr 02, 2024 at 06:27:40PM -0700, John Stultz wrote: > On Tue, Apr 2, 2024 at 6:21 PM Bongkyu Kim wrote: > > On Tue, Apr 02, 2024 at 04:46:06PM -0700, John Stultz wrote: > > > On Thu, Aug 31, 2023 at 6:07 PM Bongkyu Kim wrote: > > > > > > > > This is rework of the following discussed patch. > > > > https://lore.kernel.org/all/20230613043308.GA1027@KORCO045595.samsungds.net/ > > > > > > > > Changes from the previous patch > > > > - Split to revert and modify patches > > > > - Change according to Waiman Long's review > > > > More wording to documentation part > > > > Change module_param to early_param > > > > Code change by Waiman Long's suggestion > > > > > > > > In mobile environment, reader optimistic spinning is still useful > > > > because there're not many readers. In my test result at android device, > > > > it improves application startup time about 3.8% > > > > App startup time is most important factor for android user expriences. > > > > So, re-enable reader optimistic spinning by this commit. And, > > > > make it optional feature by cmdline. > > > > > > > > Test result: > > > > This is 15 application startup performance in our exynos soc. > > > > - Cortex A78*2 + Cortex A55*6 > > > > - unit: ms (lower is better) > > > > > > > > Application base opt_rspin Diff Diff(%) > > > > -------------------- ------ --------- ---- ------- > > > > * Total(geomean) 343 330 -13 +3.8% > > > > -------------------- ------ --------- ---- ------- > > > > helloworld 110 108 -2 +1.8% > > > > Amazon_Seller 397 388 -9 +2.3% > > > > Whatsapp 311 304 -7 +2.3% > > > > Simple_PDF_Reader 500 463 -37 +7.4% > > > > FaceApp 330 317 -13 +3.9% > > > > Timestamp_Camera_Free 451 443 -8 +1.8% > > > > Kindle 629 597 -32 +5.1% > > > > Coinbase 243 233 -10 +4.1% > > > > Firefox 425 399 -26 +6.1% > > > > Candy_Crush_Soda 552 538 -14 +2.5% > > > > Hill_Climb_Racing 245 230 -15 +6.1% > > > > Call_Recorder 437 426 -11 +2.5% > > > > Color_Fill_3D 190 180 -10 +5.3% > > > > eToro 512 505 -7 +1.4% > > > > GroupMe 281 266 -15 +5.3% > > > > > > > > > > Hey Bongkyu, > > > I wanted to reach out to see what the current status of this patch > > > set? I'm seeing other parties trying to work around the loss of the > > > optimistic spinning functionality since commit 617f3ef95177 > > > ("locking/rwsem: Remove reader optimistic spinning") as well, with > > > their own custom variants (providing some substantial gains), and > > > would really like to have a common solution. > > > > > > > I didn't get an reply, so I've been waiting. > > Could you let me know about their patch? > > I don't have insight/access to any other implementations, but I have > nudged folks to test your patch and chime in here. > > Mostly I just wanted to share that others are also seeing performance > trouble from the loss of optimistic spinning, so it would be good to > get some sort of shared solution upstream. > > thanks > -john > Thanks for your sharing! Bongkyu. ------9D_2.EQ5cGIhcMb2E9QR8GFUB51-NQQYsO-rsNzGreYF.8HD=_b7a51_ Content-Type: text/plain; charset="utf-8" ------9D_2.EQ5cGIhcMb2E9QR8GFUB51-NQQYsO-rsNzGreYF.8HD=_b7a51_--