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Wed, 2 Apr 2025 02:28:39 +0000 (GMT) Received: from epsmgms1p2new.samsung.com (unknown [182.195.42.42]) by epsmtrp2.samsung.com (KnoxPortal) with ESMTP id 20250402022839epsmtrp207b0765e1a3566a3b11851eb31b81dd6~yX2swXerG2617026170epsmtrp24; Wed, 2 Apr 2025 02:28:39 +0000 (GMT) X-AuditID: b6c32a48-b95f07000000268f-87-67eca0d8adcf Received: from epsmtip1.samsung.com ( [182.195.34.30]) by epsmgms1p2new.samsung.com (Symantec Messaging Gateway) with SMTP id 11.D6.08805.7D0ACE76; Wed, 2 Apr 2025 11:28:39 +0900 (KST) Received: from perf (unknown [10.229.95.91]) by epsmtip1.samsung.com (KnoxPortal) with ESMTPA id 20250402022839epsmtip12afaf422178eadf15f85237be9f86c93~yX2sc-fs01452614526epsmtip1X; Wed, 2 Apr 2025 02:28:39 +0000 (GMT) Date: Wed, 2 Apr 2025 11:32:57 +0900 From: Youngmin Nam To: William McVicker Cc: John Stultz , Catalin Marinas , Will Deacon , Peter Griffin , =?iso-8859-1?Q?Andr=E9?= Draszik , Tudor Ambarus , Rob Herring , Krzysztof Kozlowski , Conor Dooley , Alim Akhtar , Daniel Lezcano , Thomas Gleixner , Saravana Kannan , Krzysztof Kozlowski , kernel-team@android.com, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-samsung-soc@vger.kernel.org, devicetree@vger.kernel.org, tigersoundkim@gmail.com Subject: Re: [PATCH v1 3/6] clocksource/drivers/exynos_mct: Set local timer interrupts as percpu Message-ID: Precedence: bulk X-Mailing-List: devicetree@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 In-Reply-To: X-Brightmail-Tracker: H4sIAAAAAAAAA01Tf1DTZRzm3b77bqNbfp2YL4S0ptFJAhtt7KUDrxrVt/KC6rg4PIUBXzdk bGs/PPrhSYFKwxM0uYOpyK9iNyfgGHOohE5FggTvCjFC0CMISEBYmdcha2Oz47/nfT7P836e z33el0XnzuNhrDyVntKqZEo+How5rm6RRN+pfSAX1DQz0b0aB47sM20Ymv/+MEDWzn4aqnFv RKev9TPQUs85HDnPh6Bp0yiOBgZamcg2fpuBfr5wEkdVAz/QUGvVMoY8l5xMZHQ9wVGbrZKO bg0OYGhxeBcqGREjy6IHvL6edFx0MEhrjRWQHaa7TLLWZiBtlm9wcuT2JZyc6+9nkm2N+8kj dgsg3baI1OCM/EQFJcultDxKlaPOzVPJk/jvf5wpzRTHC4TRwgQk4fNUsgIqiZ+8PTX67Tyl dz4+b69MafBSqTKdjh+7LVGrNugpnkKt0yfxKU2uUiPRxOhkBTqDSh6jovSvCQWCOLFXmJWv OH7ATNO4OYUtvWfoRaD2GSNgsyAhgo1//YoZQTCLSzgBNM1OMfyHRQDtp44FKo8AnByqpz21 VFw5RfMXOgHs7h4LWO4DaCl3rqgwYjPstfQxfRgnoqGjZxkYAYsVQsTApQOFPj2d8DDgnXPn gU+zjsiGV+a/xXwaDrEJXq9L8dEcYi38sfp3zIfZRBScnhun+7yQKGdD55+/4P5EybDiURnm x+vgzA0704/DoHuuM6DRwaKx4YC5BMDeoSm6v/AqNE0eWglBJxTQaL7O9IWA3hDXhjE//Sws vfokQHNg6UGu3xkJ/z3eCvw4HF5sMAduJGFXU8NKWy5hpcFb9Z9WgAjTqnFMq5qZvLfSiS2w 5UKsn34BFrefoPvp52HTMmuVohbgFvAcpdEVyCldnEb0/65z1AU2sPLyo0gnODH7MMYFaCzg ApBF54dw0v+elnM5ubLPPqe06kytQUnpXEDs3dJRetj6HLX366j0mUJRgkAUHy+UxIkFEv4G jmthQs4l5DI9lU9RGkr71EdjscOKaGl9utGsobMkDTAdh3jlD7s+it8XldLeHbljh3F/NR9t tGYnz7Ijij958x2HcU2kvSp3oblsJ2PkpULzH7acmamUF5stxBvSlP57c/u23uzq7itFOYku xC9pcXTsnuC8NZV+84MKjH1m3BOy6eBOj2jhw4LLoscll4Pd6UGisLSMiL1BipfjMnavDXe3 72EebYs/6dlqHpQSE4xjEvGGSiohXfGu5r0vJtuzZkbrouzmbdt5PdIvg3/qG9QW1wiCbpzt qD/dwLkv/vofw+Dj+iawJjzu8FfSPaHGlPQy6YNY5dgrgwONprvfLVRWLw1N9iWHTrQcmRaF /pZtTdtVt7nDw8d0Cpkwiq7Vyf4DmLJZ64IEAAA= X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFjrEIsWRmVeSWpSXmKPExsWy7bCSnO71BW/SDT7+V7J4MG8bm8WWV5tZ LN4v62G0WLP3HJPFvM+yFvOPnGO1+HNiI5vFju0iFi9n3WOzOH9+A7vFpsfXWC0u75rDZjHj /D4miw0z/rFY/N+zg92i69BfNovNm6YyW1y4ep7F4tOtOIuWO6YWqz79Z3QQ9di2exurx5p5 axg9ds66y+6xYFOpx6ZVnWwed67tYfN4d+4cu8fmJfUefVtWMXp83iQXwBXFZZOSmpNZllqk b5fAlXF1yQbmgqncFd/39DA3MN7j6GLk5JAQMJGYcHAuUxcjF4eQwG5Gic+fLzFCJGQkbq+8 zAphC0vcbznCClF0n1Fi1sEZzCAJFgEViVOrTrOD2GwCuhLbTvwDaubgEBHQk/jTWgFSzyzQ ySbR/fwuE0iNsECSxMH3k1lAangFlCWOLvSHmLmGSeL43l1gc3gFBCVOznzCAmIzC6hL/Jl3 iRmknllAWmL5Pw6IsLxE89bZYCdwCmhJvHz3mHkCo+AsJN2zkHTPQuiehaR7ASPLKkbJ1ILi 3PTcYsMCo7zUcr3ixNzi0rx0veT83E2M4GjW0trBuGfVB71DjEwcjIcYJTiYlUR4I76+TBfi TUmsrEotyo8vKs1JLT7EKM3BoiTO++11b4qQQHpiSWp2ampBahFMlomDU6qBSczw6vq2L1p/ /ixS9eRevH2BekX4NHPhm6vi92S7L3FymLIiS/WZxIpiiVbfbVY2QVKyvzgmKx56J756mhOT TUnf0fO8fIf809n/lGsWJS/bttz1peNhmeCVO7dWSj/fmyvwmNM5pFLwmh3zx9AJs7fab/jP P9/yy26fLbWNnA9yz9a8bylb2xa86sqmi9vDj7m+Notmufri6fSAI/c2zf2x6OkWa4WHivXi 10u2TljKaqK8SHC1mGHQAasVs/X4NH6y7XXqsHufvetgzoOShWsTFaVOZ8zR27EqzOxX56// i69ELuXj4TuWt4LRweBuT8ymj/u368zuf61V/jVPgzPljMVFFrbFSsaK+zncdiqxFGckGmox FxUnAgBuIFEVVQMAAA== X-CMS-MailID: 20250402022839epcas2p418dd591006fe8a00ecba240a3b60baaf X-Msg-Generator: CA Content-Type: multipart/mixed; boundary="-----xErIy8MFyp5znNcbVfGOYxfVuB8z5fzEV-ls754GuccR_q1=_74052_" X-Sendblock-Type: AUTO_CONFIDENTIAL CMS-TYPE: 102P DLP-Filter: Pass X-CFilter-Loop: Reflected X-CMS-RootMailID: 20250401163914epcas2p1a16e2b7a6ecac9f010ef6eb4c8efc6fb References: <20250331230034.806124-1-willmcvicker@google.com> <20250331230034.806124-4-willmcvicker@google.com> -------xErIy8MFyp5znNcbVfGOYxfVuB8z5fzEV-ls754GuccR_q1=_74052_ Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 8bit Content-Disposition: inline On Tue, Apr 01, 2025 at 09:36:19AM -0700, William McVicker wrote: > On 03/31/2025, John Stultz wrote: > > On Mon, Mar 31, 2025 at 4:00 PM 'Will McVicker' via kernel-team > > wrote: > > > > > > From: Hosung Kim > > > > > > The MCT local timers can be used as a per-cpu event timer. To prevent > > > > Can be used, or are used? If it's an option, is this change important > > in both cases? > > > > > the timer interrupts from migrating to other CPUs, set the flag > > > IRQF_PERCPU. > > > > Might be work expanding this a bit to clarify why the interrupts > > migrating to other cpus is undesired. > > Let me dig into this further to figure out if the IP has a limitation where the > interrupts need to be handled by the CPU the timer was triggered on or if this > is just an optimization. > > Any chance you know this @Youngmin? > > Thanks, > Will > Hi Will. Yes. In downstream, we’ve been using MCT as the clock event timer instead of the ARM timer. Setting this flag allows each CPU to handle its own clock events, such as scheduling interrupts. > > > > > Signed-off-by: Hosung Kim > > > [Original commit from https://android.googlesource.com/kernel/gs/+/03267fad19f093bac979ca78309483e9eb3a8d16] > > > Signed-off-by: Will McVicker > > > > thanks! > > -john > > -------xErIy8MFyp5znNcbVfGOYxfVuB8z5fzEV-ls754GuccR_q1=_74052_ Content-Type: text/plain; charset="utf-8" -------xErIy8MFyp5znNcbVfGOYxfVuB8z5fzEV-ls754GuccR_q1=_74052_--