arm64: rk3399: Add capacity-dmips-mhz attributes
diff mbox series

Message ID 20190224143525.15539-1-marc.zyngier@arm.com
State New
Headers show
Series
  • arm64: rk3399: Add capacity-dmips-mhz attributes
Related show

Commit Message

Marc Zyngier Feb. 24, 2019, 2:35 p.m. UTC
The RK3399 has the interesting property to be a so called "big-little"
system, where not all the CPUs are equal (the A53s are much weaker
than the A72s).

So far, we're not telling the OS that there is such a difference in
processing capacity, and Linux assumes that they are equal. Too bad.

Let's tell the OS about this by using the capacity-dmips-mhz
property. The values used here are those used on the Juno platform,
which is quite similar. This leads to the scheduler knowing that
it can pack more tasks on the A72s, and leads to a better interactive
experience.

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
 arch/arm64/boot/dts/rockchip/rk3399.dtsi | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

Comments

Robin Murphy Feb. 24, 2019, 8:07 p.m. UTC | #1
Hi Marc,

On 2019-02-24 2:35 pm, Marc Zyngier wrote:
> The RK3399 has the interesting property to be a so called "big-little"
> system, where not all the CPUs are equal (the A53s are much weaker
> than the A72s).
> 
> So far, we're not telling the OS that there is such a difference in
> processing capacity, and Linux assumes that they are equal. Too bad.
> 
> Let's tell the OS about this by using the capacity-dmips-mhz
> property. The values used here are those used on the Juno platform,
> which is quite similar. This leads to the scheduler knowing that
> it can pack more tasks on the A72s, and leads to a better interactive
> experience.
> 
> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
> ---
>   arch/arm64/boot/dts/rockchip/rk3399.dtsi | 7 ++++++-
>   1 file changed, 6 insertions(+), 1 deletion(-)
> 
> diff --git a/arch/arm64/boot/dts/rockchip/rk3399.dtsi b/arch/arm64/boot/dts/rockchip/rk3399.dtsi
> index 6cc1c9fa4ea6..7eab31184aee 100644
> --- a/arch/arm64/boot/dts/rockchip/rk3399.dtsi
> +++ b/arch/arm64/boot/dts/rockchip/rk3399.dtsi
> @@ -75,6 +75,7 @@
>   			#cooling-cells = <2>; /* min followed by max */
>   			dynamic-power-coefficient = <100>;
>   			cpu-idle-states = <&CPU_SLEEP &CLUSTER_SLEEP>;
> +			capacity-dmips-mhz = <578>;

Probably better to use the value from Juno r2 (485) which should more 
appropriately represent A53 vs. A72, rather than A53 vs. A57.

>   		};
>   
>   		cpu_l1: cpu@1 {
> @@ -86,6 +87,7 @@
>   			#cooling-cells = <2>; /* min followed by max */
>   			dynamic-power-coefficient = <100>;
>   			cpu-idle-states = <&CPU_SLEEP &CLUSTER_SLEEP>;
> +			capacity-dmips-mhz = <578>;
>   		};
>   
>   		cpu_l2: cpu@2 {
> @@ -97,6 +99,7 @@
>   			#cooling-cells = <2>; /* min followed by max */
>   			dynamic-power-coefficient = <100>;
>   			cpu-idle-states = <&CPU_SLEEP &CLUSTER_SLEEP>;
> +			capacity-dmips-mhz = <578>;
>   		};
>   
>   		cpu_l3: cpu@3 {
> @@ -108,6 +111,7 @@
>   			#cooling-cells = <2>; /* min followed by max */
>   			dynamic-power-coefficient = <100>;
>   			cpu-idle-states = <&CPU_SLEEP &CLUSTER_SLEEP>;
> +			capacity-dmips-mhz = <578>;
>   		};
>   
>   		cpu_b0: cpu@100 {
> @@ -118,7 +122,7 @@
>   			clocks = <&cru ARMCLKB>;
>   			#cooling-cells = <2>; /* min followed by max */
>   			dynamic-power-coefficient = <436>;
> -			cpu-idle-states = <&CPU_SLEEP &CLUSTER_SLEEP>;

Oops.

Otherwise, though, I was on the verge of tackling this myself now that 
my 3399 board is building its own kernels - annoyance at the linking 
bottleneck steadfastly refusing to move off CPU0 (except occasionally to 
another little core) has been growing steadily :) With the nits fixed,

Tested-by: Robin Murphy <robin.murphy@arm.com>

Cheers,
Robin.

> +			capacity-dmips-mhz = <1024>;
>   		};
>   
>   		cpu_b1: cpu@101 {
> @@ -130,6 +134,7 @@
>   			#cooling-cells = <2>; /* min followed by max */
>   			dynamic-power-coefficient = <436>;
>   			cpu-idle-states = <&CPU_SLEEP &CLUSTER_SLEEP>;
> +			capacity-dmips-mhz = <1024>;
>   		};
>   
>   		idle-states {
>
Marc Zyngier Feb. 24, 2019, 9:06 p.m. UTC | #2
On Sun, 24 Feb 2019 20:07:49 +0000
Robin Murphy <robin.murphy@arm.com> wrote:

Hi Robin,

> Hi Marc,
> 
> On 2019-02-24 2:35 pm, Marc Zyngier wrote:
> > The RK3399 has the interesting property to be a so called "big-little"
> > system, where not all the CPUs are equal (the A53s are much weaker
> > than the A72s).
> > 
> > So far, we're not telling the OS that there is such a difference in
> > processing capacity, and Linux assumes that they are equal. Too bad.
> > 
> > Let's tell the OS about this by using the capacity-dmips-mhz
> > property. The values used here are those used on the Juno platform,
> > which is quite similar. This leads to the scheduler knowing that
> > it can pack more tasks on the A72s, and leads to a better interactive
> > experience.
> > 
> > Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
> > ---
> >   arch/arm64/boot/dts/rockchip/rk3399.dtsi | 7 ++++++-
> >   1 file changed, 6 insertions(+), 1 deletion(-)
> > 
> > diff --git a/arch/arm64/boot/dts/rockchip/rk3399.dtsi b/arch/arm64/boot/dts/rockchip/rk3399.dtsi
> > index 6cc1c9fa4ea6..7eab31184aee 100644
> > --- a/arch/arm64/boot/dts/rockchip/rk3399.dtsi
> > +++ b/arch/arm64/boot/dts/rockchip/rk3399.dtsi
> > @@ -75,6 +75,7 @@
> >   			#cooling-cells = <2>; /* min followed by max */
> >   			dynamic-power-coefficient = <100>;
> >   			cpu-idle-states = <&CPU_SLEEP &CLUSTER_SLEEP>;
> > +			capacity-dmips-mhz = <578>;  
> 
> Probably better to use the value from Juno r2 (485) which should more
> appropriately represent A53 vs. A72, rather than A53 vs. A57.

Indeed. Although I doubt that there is such a difference between A57
and A72, but I guess it won't really show.

> >   		};  
> >   >   		cpu_l1: cpu@1 {  
> > @@ -86,6 +87,7 @@
> >   			#cooling-cells = <2>; /* min followed by
> > max */ dynamic-power-coefficient = <100>;
> >   			cpu-idle-states = <&CPU_SLEEP
> > &CLUSTER_SLEEP>;
> > +			capacity-dmips-mhz = <578>;
> >   		};  
> >   >   		cpu_l2: cpu@2 {  
> > @@ -97,6 +99,7 @@
> >   			#cooling-cells = <2>; /* min followed by
> > max */ dynamic-power-coefficient = <100>;
> >   			cpu-idle-states = <&CPU_SLEEP
> > &CLUSTER_SLEEP>;
> > +			capacity-dmips-mhz = <578>;
> >   		};  
> >   >   		cpu_l3: cpu@3 {  
> > @@ -108,6 +111,7 @@
> >   			#cooling-cells = <2>; /* min followed by
> > max */ dynamic-power-coefficient = <100>;
> >   			cpu-idle-states = <&CPU_SLEEP
> > &CLUSTER_SLEEP>;
> > +			capacity-dmips-mhz = <578>;
> >   		};  
> >   >   		cpu_b0: cpu@100 {  
> > @@ -118,7 +122,7 @@
> >   			clocks = <&cru ARMCLKB>;
> >   			#cooling-cells = <2>; /* min followed by
> > max */ dynamic-power-coefficient = <436>;
> > -			cpu-idle-states = <&CPU_SLEEP
> > &CLUSTER_SLEEP>;  
> 
> Oops.

Gahhhh! Rebase fail. What an idiot. Thanks for spotting this!

> 
> Otherwise, though, I was on the verge of tackling this myself now
> that my 3399 board is building its own kernels - annoyance at the
> linking bottleneck steadfastly refusing to move off CPU0 (except
> occasionally to another little core) has been growing steadily :)

Yeah, tell me about it. I still regularly build the kernel on my kevin,
and while the compilation time is reasonable for this kind of device
(and the storage media being an sdcard), the linking is just a pig.
Even on the A72.

> With the nits fixed,
> 
> Tested-by: Robin Murphy <robin.murphy@arm.com>

Cheers Robin. I'll post a v2 after -rc1.

	M.
Heiko Stuebner March 2, 2019, 12:39 p.m. UTC | #3
Hi Marc,

Am Sonntag, 24. Februar 2019, 22:06:57 CET schrieb Marc Zyngier:
> On Sun, 24 Feb 2019 20:07:49 +0000
> Robin Murphy <robin.murphy@arm.com> wrote:

[...]

> > With the nits fixed,
> > 
> > Tested-by: Robin Murphy <robin.murphy@arm.com>
> 
> Cheers Robin. I'll post a v2 after -rc1.

You can do that earlier as well, if you want to get it off your plate :-)
I'm normally not pausing patches over the merge-window, so from
my side there is no need to wait for rc1.

Heiko
Marc Zyngier March 2, 2019, 1:11 p.m. UTC | #4
On Sat, 2 Mar 2019 13:39:38 +0100
Heiko Stuebner <heiko@sntech.de> wrote:

Hi Heiko,

> Hi Marc,
> 
> Am Sonntag, 24. Februar 2019, 22:06:57 CET schrieb Marc Zyngier:
> > On Sun, 24 Feb 2019 20:07:49 +0000
> > Robin Murphy <robin.murphy@arm.com> wrote:  
> 
> [...]
> 
> > > With the nits fixed,
> > > 
> > > Tested-by: Robin Murphy <robin.murphy@arm.com>  
> > 
> > Cheers Robin. I'll post a v2 after -rc1.  
> 
> You can do that earlier as well, if you want to get it off your plate :-)
> I'm normally not pausing patches over the merge-window, so from
> my side there is no need to wait for rc1.

Your wish is my command! ;-) v2 on its way.

Thanks,

	M.
Heiko Stuebner March 2, 2019, 2:10 p.m. UTC | #5
Am Samstag, 2. März 2019, 14:11:22 CET schrieb Marc Zyngier:
> On Sat, 2 Mar 2019 13:39:38 +0100
> Heiko Stuebner <heiko@sntech.de> wrote:
> 
> Hi Heiko,
> 
> > Hi Marc,
> > 
> > Am Sonntag, 24. Februar 2019, 22:06:57 CET schrieb Marc Zyngier:
> > > On Sun, 24 Feb 2019 20:07:49 +0000
> > > Robin Murphy <robin.murphy@arm.com> wrote:  
> > 
> > [...]
> > 
> > > > With the nits fixed,
> > > > 
> > > > Tested-by: Robin Murphy <robin.murphy@arm.com>  
> > > 
> > > Cheers Robin. I'll post a v2 after -rc1.  
> > 
> > You can do that earlier as well, if you want to get it off your plate :-)
> > I'm normally not pausing patches over the merge-window, so from
> > my side there is no need to wait for rc1.
> 
> Your wish is my command! ;-) v2 on its way.

that even worked without sudo :-P [0] ... I need to remember that
for when we run into each other the next time.


[0] https://xkcd.com/149/

Patch
diff mbox series

diff --git a/arch/arm64/boot/dts/rockchip/rk3399.dtsi b/arch/arm64/boot/dts/rockchip/rk3399.dtsi
index 6cc1c9fa4ea6..7eab31184aee 100644
--- a/arch/arm64/boot/dts/rockchip/rk3399.dtsi
+++ b/arch/arm64/boot/dts/rockchip/rk3399.dtsi
@@ -75,6 +75,7 @@ 
 			#cooling-cells = <2>; /* min followed by max */
 			dynamic-power-coefficient = <100>;
 			cpu-idle-states = <&CPU_SLEEP &CLUSTER_SLEEP>;
+			capacity-dmips-mhz = <578>;
 		};
 
 		cpu_l1: cpu@1 {
@@ -86,6 +87,7 @@ 
 			#cooling-cells = <2>; /* min followed by max */
 			dynamic-power-coefficient = <100>;
 			cpu-idle-states = <&CPU_SLEEP &CLUSTER_SLEEP>;
+			capacity-dmips-mhz = <578>;
 		};
 
 		cpu_l2: cpu@2 {
@@ -97,6 +99,7 @@ 
 			#cooling-cells = <2>; /* min followed by max */
 			dynamic-power-coefficient = <100>;
 			cpu-idle-states = <&CPU_SLEEP &CLUSTER_SLEEP>;
+			capacity-dmips-mhz = <578>;
 		};
 
 		cpu_l3: cpu@3 {
@@ -108,6 +111,7 @@ 
 			#cooling-cells = <2>; /* min followed by max */
 			dynamic-power-coefficient = <100>;
 			cpu-idle-states = <&CPU_SLEEP &CLUSTER_SLEEP>;
+			capacity-dmips-mhz = <578>;
 		};
 
 		cpu_b0: cpu@100 {
@@ -118,7 +122,7 @@ 
 			clocks = <&cru ARMCLKB>;
 			#cooling-cells = <2>; /* min followed by max */
 			dynamic-power-coefficient = <436>;
-			cpu-idle-states = <&CPU_SLEEP &CLUSTER_SLEEP>;
+			capacity-dmips-mhz = <1024>;
 		};
 
 		cpu_b1: cpu@101 {
@@ -130,6 +134,7 @@ 
 			#cooling-cells = <2>; /* min followed by max */
 			dynamic-power-coefficient = <436>;
 			cpu-idle-states = <&CPU_SLEEP &CLUSTER_SLEEP>;
+			capacity-dmips-mhz = <1024>;
 		};
 
 		idle-states {