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Thu, 3 Apr 2025 23:57:52 +0000 (GMT) X-AuditID: b6c32a48-b7fff7000000268f-e8-67ef2081e7e3 Received: from epsmtip1.samsung.com ( [182.195.34.30]) by epsmgms1p2new.samsung.com (Symantec Messaging Gateway) with SMTP id A7.C6.08805.0802FE76; Fri, 4 Apr 2025 08:57:52 +0900 (KST) Received: from perf (unknown [10.229.95.91]) by epsmtip1.samsung.com (KnoxPortal) with ESMTPA id 20250403235752epsmtip1465881f309eff79f043b5d2e8e0b2852~y9FnXfgci2285222852epsmtip1D; Thu, 3 Apr 2025 23:57:52 +0000 (GMT) Date: Fri, 4 Apr 2025 09:02:08 +0900 From: Youngmin Nam To: William McVicker Cc: 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 , 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, Will Deacon , Youngmin Nam Subject: Re: [PATCH v1 4/6] arm64: dts: exynos: gs101: Add 'local-timer-stop' to cpuidle nodes Message-ID: MIME-Version: 1.0 In-Reply-To: X-Brightmail-Tracker: H4sIAAAAAAAAA01TfUxTVxTn9r0+Xp0sj8rYlVWC3TCDDGihhQsKM0HnS7ZlJGQZTDN4oW8t o7RNX2tA3cQJAzo14uTDrsOqREwDgRXokC9dIfFjBBATTDo2ZuYIH1NmkW7igLU8XPzvd879 /c75nXvuJTGxh4ggC3Um1qhjtFJiE+4ajFHGHYtaUMssKzj6rdFFoM65DhwtXD4BUEv/iAA1 Lm5D54dGhKj7hzA0a/2VQM7fJ4Tobo+NQA2jAwLU3rCKo7W+7mBkca8QqMNZiyGv5xNUPqlE lU/nceTwrgF06bo3eHcY7ep1CemWxhZA251m2umoJujJiT6CfjQyEkx3NB2lT3U6AL3ojMwS fVy0S8MyKtYYxeoK9KpCnTpd+m52XmaeMlkmj5OnohRplI4pZtOle97LinunUOufShp1kNGa /akshuOkCRm7jHqziY3S6DlTupQ1qLSGFEM8xxRzZp06Xsea0uQyWaLST8wv0lwe/8jwzY6S pnPNeBl4ss0CRCSkFPD4nUncAjaRYqobwLrb9RgfeAGcH7cLAiwx5QPw6592Plf8Yh3cUPQD 6FtaAnxwH8Bnvht4gIVTb8BKr20dE1QcdN1c9ZNIMoyKh/9WlAT4GDUrhKdcMyDA2ULlwzsD c8IADqFeh2dnr2I8DoW3zj1YryOiYuH9oZl1e5B6QMJ2uzuYt7QH/l37s5DHW+Dcjc6NfARc fNRP8JiDZVOeDXE5gLfvzWD8QRK0Tleuu8AoDey9O4wFnEK/iyEPzqdfhlWDK8F8OgRWfSXm lTvg8tl2wGMJ7L10ZaMiDbvWXAR/KV0CaG8bxk+DSOsL81hf6Mbjt6C910tY/S0w6jXYvEry MAa29STYgdABwlkDV6xmuUSD4v8FF+iLnWD9kcfS3eDbh3/Fu4GABG4ASUwaFjIjWVCLQ1RM 6SHWqM8zmrUs5wZK/3JqsIhXCvT+X6Iz5ckVqTJFcrI8JVEpS5G+GuJ+/IdaTKkZE1vEsgbW +FwnIEURZYJ9vhqD7LMcT+Y+RZYlyaep2MncXH76eMKe3bT1grx0rLLnIqkSJsYcQs0OZ9tg ZOqbrVz3Ulrm7qDPWyckDxOmrOXVQZuL+tIMs2u12fPP4kyd8zUnfeGHo7Gq+u8cw5vPf7B6 RrUV/Hi6rjqHnvknuitXlhZbG5oznn/RrM3cb/PsNQ4e8eaGwmvCubCMAsN1b6Pkz9z9S4bt OccGxhbfLrXIM4IqRO6+J/prdSeu1Fw4MtV6RpW4nD3deXU5iVq0yfq7Glrst4AkTyhaUI+B VAs4ePwLUZVbrvkw7Uvv+/cOY9G04OT2iPLeo6OTnyoqSg6Mfn9AYntptn7aGS7FOQ0jj8WM HPMfDGQsKW0EAAA= X-Brightmail-Tracker: H4sIAAAAAAAAA02RW0xScRzH9+dcPLDRjkj5T5EampUmpeX6t6x1mx7rIX1os5Yp5YksQYJM rQetLIwua5pLmWIX0yKXhoqIwgy1VUtzubDZRV21BbZM2UqXUaFr9fb5fW8vPwoT3MCDqEzl MVatlGVJSB5u7pKIowoXj8tXjdjC0IjBTKJmdxOOxmsvAlRv6+MggycEVXf3EcjSKkQu/TsS md47CTRgrSRR+XM7BzWWe3H0q8Pih3SOnyRqMpVhaHJoHyp6E4u002M4Mk7+AuhW56TfJiFj bjcTTL2hHjDXTTmMyXieZN44O0jmS1+fH9NUU8BcbjYCxmMSJ3H38OIy2KzM46x65cZ03qHe wVukaiA075zeShaC3mAd4FKQXgPf6rtwHeBRArodwObbvsNniODruwPEHAfA4aJuYi40DGDr S9dsCKfDoHaycpZJOgqaH3uBDlCUkJbCmbN5vjxGewjYUtyD+TIBdDp8Ufya42M+HQqvutqw udE2Duy/8BifM/zhk4oPs4zREfCV18XxjWJ0MKzzUj6Z+0ce7f6EXQG0/r+G/r+G/l/jOsCM YCGr0ijkCk20KkbJ5ko1MoUmRymXHshWmMDsFyMiLKDD+FXqABwKOACkMImQ/0k0LhfwM2T5 J1h1dpo6J4vVOEAwhUsC+d/GLmUIaLnsGHuEZVWs+q/LobhBhZy92VfonftPHm66506oWrco ZFRCZm31cD3XJuLskWE9Bul2/xF7dSrhjoWrc+PW1mrFG6pr1ht+PBLFMzHbVihipkpCdfOS G9vzRxb0prlqH6V8kRYnFczbalM3bICtpTsuhXz2ipJGR9ecThhf6zjYWFHTVRHbEn1mIMXj ke+KsU5XLq9W2XgPT2lEz84tis3jz8dJt1s0mGpK2EeF+2uJZEsvf0kar2TB/curyxLtM4na oc6b4siLaPMdfb8FdKm/C5wN/bLCox+r0scmHNS3LTny5VtShyfsIDyzvq7xaYs8UEJM7XEK a4vi85Y1c1udH/EHp0t3WxuCsKUSXHNIFh2BqTWy32UE4mc0AwAA X-CMS-MailID: 20250403235752epcas2p192712bf4c5cbf0fda2c9b1dc71d3ac61 X-Msg-Generator: CA Content-Type: multipart/mixed; boundary="----rHPRFtJkdx5CiZJP2v5Cn8OZ9YZY2B0tfPkXi2gvBl6TiQFm=_8b7dd_" X-Sendblock-Type: AUTO_CONFIDENTIAL CMS-TYPE: 102P DLP-Filter: Pass X-CFilter-Loop: Reflected X-CMS-RootMailID: 20250331230151epcas2p486a7c6d7153737f4168cfef74249742f References: <20250331230034.806124-1-willmcvicker@google.com> <20250331230034.806124-5-willmcvicker@google.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20250403_165802_785280_7B022023 X-CRM114-Status: GOOD ( 41.01 ) 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: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org ------rHPRFtJkdx5CiZJP2v5Cn8OZ9YZY2B0tfPkXi2gvBl6TiQFm=_8b7dd_ Content-Type: text/plain; charset="us-ascii" Content-Disposition: inline On Thu, Apr 03, 2025 at 11:39:23AM -0700, William McVicker wrote: > On 04/03/2025, Youngmin Nam wrote: > > On Wed, Apr 02, 2025 at 02:59:31PM -0700, William McVicker wrote: > > > Hi Youngmin, > > > > > > On 04/02/2025, Youngmin Nam wrote: > > > > On Mon, Mar 31, 2025 at 04:00:26PM -0700, Will McVicker wrote: > > > > > From: Will Deacon > > > > > > > > > > In preparation for switching to the architected timer as the primary > > > > > clockevents device, mark the cpuidle nodes with the 'local-timer-stop' > > > > > property to indicate that an alternative clockevents device must be > > > > > used for waking up from the "c2" idle state. > > > > > > > > > > Signed-off-by: Will Deacon > > > > > [Original commit from https://android.googlesource.com/kernel/gs/+/a896fd98638047989513d05556faebd28a62b27c] > > > > > Signed-off-by: Will McVicker > > > > > --- > > > > > arch/arm64/boot/dts/exynos/google/gs101.dtsi | 3 +++ > > > > > 1 file changed, 3 insertions(+) > > > > > > > > > > diff --git a/arch/arm64/boot/dts/exynos/google/gs101.dtsi b/arch/arm64/boot/dts/exynos/google/gs101.dtsi > > > > > index 3de3a758f113..fd0badf24e6f 100644 > > > > > --- a/arch/arm64/boot/dts/exynos/google/gs101.dtsi > > > > > +++ b/arch/arm64/boot/dts/exynos/google/gs101.dtsi > > > > > @@ -155,6 +155,7 @@ ananke_cpu_sleep: cpu-ananke-sleep { > > > > > idle-state-name = "c2"; > > > > > compatible = "arm,idle-state"; > > > > > arm,psci-suspend-param = <0x0010000>; > > > > > + local-timer-stop; > > > > > entry-latency-us = <70>; > > > > > exit-latency-us = <160>; > > > > > min-residency-us = <2000>; > > > > > @@ -164,6 +165,7 @@ enyo_cpu_sleep: cpu-enyo-sleep { > > > > > idle-state-name = "c2"; > > > > > compatible = "arm,idle-state"; > > > > > arm,psci-suspend-param = <0x0010000>; > > > > > + local-timer-stop; > > > > > entry-latency-us = <150>; > > > > > exit-latency-us = <190>; > > > > > min-residency-us = <2500>; > > > > > @@ -173,6 +175,7 @@ hera_cpu_sleep: cpu-hera-sleep { > > > > > idle-state-name = "c2"; > > > > > compatible = "arm,idle-state"; > > > > > arm,psci-suspend-param = <0x0010000>; > > > > > + local-timer-stop; > > > > > entry-latency-us = <235>; > > > > > exit-latency-us = <220>; > > > > > min-residency-us = <3500>; > > > > > -- > > > > > 2.49.0.472.ge94155a9ec-goog > > > > > > > > > Hi Will. > > > > > > > > Are you using this property in production? > > > > If so, have you noticed any performance improvements? > > > > > > On Pixel 6, I have only recently switched to using the arch_timer as the > > > default clocksource. I haven't noticed any major perf improvements to the main > > > benchmarks, but also haven't seen any regressions. Based on the ChromeOS perf > > > analysis in [1,2], there was a significant perf difference found. > > > > > > [1] https://lore.kernel.org/linux-samsung-soc/CAJFHJrrgWGc4XGQB0ysLufAg3Wouz-aYXu97Sy2Kp=HzK+akVQ@mail.gmail.com/ > > > [2] https://lore.kernel.org/linux-samsung-soc/CAASgrz2Nr69tpfC8ka9gbs2OvjLEGsvgAj4vBCFxhsamuFum7w@mail.gmail.com/ > > > > > > If it helps, I found that Pixel 8 and 9 devices (didn't check Pixel 7) > > > are already using the arch_timer with this 'local-timer-stop' as the default > > > clocksource in the production kernel. > > > > > > Thanks, > > > Will > > > > > > [...] > > > > > > > Hi Will, > > > > Thanks for sharing the status of Pixel devices. > > > > I agree that using the arch_timer as a clock source device brings significant benefits. > > The links you shared are definitely related to that. > > > > However, I would also like to know whether arch_timer is used as a clock event device in Pixel production. > > For Pixel 8 and 9, the arch_timer is used as both the clocksource and > clockevent device which is what my series is proposing for Pixel 6 upstream. > The MCT device is solely being used as the alternative clockevents device for > waking up from the "c2" state. The reason for using the arch_timer as the > clockevents device is because we were seeing hrtimer stability issues where > a 10ms interval timer would delay about 300ms-1s before starting the callback. > This resulted in several media-related latency issues. > > Thanks, > Will > > [...] > Thank you for sharing your valuable experience. That will be helpful to us. Thanks, Youngmin ------rHPRFtJkdx5CiZJP2v5Cn8OZ9YZY2B0tfPkXi2gvBl6TiQFm=_8b7dd_ Content-Type: text/plain; charset="utf-8" ------rHPRFtJkdx5CiZJP2v5Cn8OZ9YZY2B0tfPkXi2gvBl6TiQFm=_8b7dd_--