| Message ID | 20250331230034.806124-5-willmcvicker@google.com |
|---|---|
| State | Superseded |
| Headers | show |
| Series | Add module support for Arm64 Exynos MCT driver | expand |
On Mon, Mar 31, 2025 at 04:00:26PM -0700, Will McVicker wrote: > From: Will Deacon <willdeacon@google.com> > > 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 <willdeacon@google.com> > [Original commit from https://android.googlesource.com/kernel/gs/+/a896fd98638047989513d05556faebd28a62b27c] > Signed-off-by: Will McVicker <willmcvicker@google.com> > --- > 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? Thanks. Youngmin
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 <willdeacon@google.com> > > > > 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 <willdeacon@google.com> > > [Original commit from https://android.googlesource.com/kernel/gs/+/a896fd98638047989513d05556faebd28a62b27c] > > Signed-off-by: Will McVicker <willmcvicker@google.com> > > --- > > 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 [...]
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>;