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[PATCH v2] cpuidle: psci: Add trace for PSCI domain idle

Keita Morisaki posted 1 patch 1 year ago
There is a newer version of this series
drivers/cpuidle/cpuidle-psci.c |  3 +++
include/trace/events/power.h   | 37 ++++++++++++++++++++++++++++++++++
2 files changed, 40 insertions(+)
[PATCH v2] cpuidle: psci: Add trace for PSCI domain idle
Posted by Keita Morisaki 1 year ago 
The trace event cpu_idle provides insufficient information for debugging
PSCI requests due to lacking access to determined PSCI domain idle
states. The cpu_idle usually only shows -1, 0, or 1 regardless how many
idle states the power domain has.

Add new trace events namely psci_domain_idle_enter and
psci_domain_idle_exit to trace enter and exit events with a determined
idle state.

These new trace events will help developers debug CPUidle issues on ARM
systems using PSCI by providing more detailed information about the
requested idle states.

Signed-off-by: Keita Morisaki <keyz@google.com>
---
v1->v2: Split the ftrace event into two (psci_domain_idle_(enter|exit))
		and rephrase the commit message accordingly. Rebased onto the latest.

 drivers/cpuidle/cpuidle-psci.c |  3 +++
 include/trace/events/power.h   | 37 ++++++++++++++++++++++++++++++++++
 2 files changed, 40 insertions(+)

diff --git a/drivers/cpuidle/cpuidle-psci.c b/drivers/cpuidle/cpuidle-psci.c
index 2562dc001fc1..dd8d776d6e39 100644
--- a/drivers/cpuidle/cpuidle-psci.c
+++ b/drivers/cpuidle/cpuidle-psci.c
@@ -25,6 +25,7 @@
 #include <linux/syscore_ops.h>

 #include <asm/cpuidle.h>
+#include <trace/events/power.h>

 #include "cpuidle-psci.h"
 #include "dt_idle_states.h"
@@ -74,7 +75,9 @@ static __cpuidle int __psci_enter_domain_idle_state(struct cpuidle_device *dev,
 	if (!state)
 		state = states[idx];

+	trace_psci_domain_idle_enter(dev->cpu, state, s2idle);
 	ret = psci_cpu_suspend_enter(state) ? -1 : idx;
+	trace_psci_domain_idle_exit(dev->cpu, state, s2idle);

 	if (s2idle)
 		dev_pm_genpd_resume(pd_dev);
diff --git a/include/trace/events/power.h b/include/trace/events/power.h
index d2349b6b531a..9253e83b9bb4 100644
--- a/include/trace/events/power.h
+++ b/include/trace/events/power.h
@@ -62,6 +62,43 @@ TRACE_EVENT(cpu_idle_miss,
 		(unsigned long)__entry->state, (__entry->below)?"below":"above")
 );

+DECLARE_EVENT_CLASS(psci_domain_idle,
+
+	TP_PROTO(unsigned int cpu_id, unsigned int state, bool s2idle),
+
+	TP_ARGS(cpu_id, state, s2idle),
+
+	TP_STRUCT__entry(
+		__field(u32,		cpu_id)
+		__field(u32,		state)
+		__field(bool,		s2idle)
+	),
+
+	TP_fast_assign(
+		__entry->cpu_id = cpu_id;
+		__entry->state = state;
+		__entry->s2idle = s2idle;
+	),
+
+	TP_printk("cpu_id=%lu state=0x%lx is_s2idle=%s",
+		  (unsigned long)__entry->cpu_id, (unsigned long)__entry->state,
+		  (__entry->s2idle)?"yes":"no")
+);
+
+DEFINE_EVENT(psci_domain_idle, psci_domain_idle_enter,
+
+	TP_PROTO(unsigned int cpu_id, unsigned int state, bool s2idle),
+
+	TP_ARGS(cpu_id, state, s2idle)
+);
+
+DEFINE_EVENT(psci_domain_idle, psci_domain_idle_exit,
+
+	TP_PROTO(unsigned int cpu_id, unsigned int state, bool s2idle),
+
+	TP_ARGS(cpu_id, state, s2idle)
+);
+
 TRACE_EVENT(powernv_throttle,

 	TP_PROTO(int chip_id, const char *reason, int pmax),

base-commit: ffd294d346d185b70e28b1a28abe367bbfe53c04
--
2.48.0.rc2.279.g1de40edade-goog
Re: [PATCH v2] cpuidle: psci: Add trace for PSCI domain idle
Posted by Christian Loehle 1 year ago 
On 1/20/25 01:36, Keita Morisaki wrote:
> The trace event cpu_idle provides insufficient information for debugging
> PSCI requests due to lacking access to determined PSCI domain idle
> states. The cpu_idle usually only shows -1, 0, or 1 regardless how many
> idle states the power domain has.
> 
> Add new trace events namely psci_domain_idle_enter and
> psci_domain_idle_exit to trace enter and exit events with a determined
> idle state.
> 
> These new trace events will help developers debug CPUidle issues on ARM
> systems using PSCI by providing more detailed information about the
> requested idle states.
> 
> Signed-off-by: Keita Morisaki <keyz@google.com>
> ---
> v1->v2: Split the ftrace event into two (psci_domain_idle_(enter|exit))
> 		and rephrase the commit message accordingly. Rebased onto the latest.


Which makes it different to cpu_idle event FWIW.

> 
>  drivers/cpuidle/cpuidle-psci.c |  3 +++
>  include/trace/events/power.h   | 37 ++++++++++++++++++++++++++++++++++
>  2 files changed, 40 insertions(+)
> 
> diff --git a/drivers/cpuidle/cpuidle-psci.c b/drivers/cpuidle/cpuidle-psci.c
> index 2562dc001fc1..dd8d776d6e39 100644
> --- a/drivers/cpuidle/cpuidle-psci.c
> +++ b/drivers/cpuidle/cpuidle-psci.c
> @@ -25,6 +25,7 @@
>  #include <linux/syscore_ops.h>
> 
>  #include <asm/cpuidle.h>
> +#include <trace/events/power.h>
> 
>  #include "cpuidle-psci.h"
>  #include "dt_idle_states.h"
> @@ -74,7 +75,9 @@ static __cpuidle int __psci_enter_domain_idle_state(struct cpuidle_device *dev,
>  	if (!state)
>  		state = states[idx];
> 
> +	trace_psci_domain_idle_enter(dev->cpu, state, s2idle);
>  	ret = psci_cpu_suspend_enter(state) ? -1 : idx;
> +	trace_psci_domain_idle_exit(dev->cpu, state, s2idle);

Not tracking ret seems odd, is that fine?
Re: [PATCH v2] cpuidle: psci: Add trace for PSCI domain idle
Posted by Keita Morisaki 1 year ago 
> > The trace event cpu_idle provides insufficient information for debugging
> > PSCI requests due to lacking access to determined PSCI domain idle
> > states. The cpu_idle usually only shows -1, 0, or 1 regardless how many
> > idle states the power domain has.
> >
> > Add new trace events namely psci_domain_idle_enter and
> > psci_domain_idle_exit to trace enter and exit events with a determined
> > idle state.
> >
> > These new trace events will help developers debug CPUidle issues on ARM
> > systems using PSCI by providing more detailed information about the
> > requested idle states.
> >
> > Signed-off-by: Keita Morisaki <keyz@google.com>
> > ---
> > v1->v2: Split the ftrace event into two (psci_domain_idle_(enter|exit))
> > 		and rephrase the commit message accordingly. Rebased onto the latest.
> Which makes it different to cpu_idle event FWIW.

Yes, psci_domain_idle_(enter|exit) are not meant to replace cpu_idle nor a
variant of it. It's new and different events that provide finer=grained info.

> >  drivers/cpuidle/cpuidle-psci.c |  3 +++
> >  include/trace/events/power.h   | 37 ++++++++++++++++++++++++++++++++++
> >  2 files changed, 40 insertions(+)
> >
> > diff --git a/drivers/cpuidle/cpuidle-psci.c b/drivers/cpuidle/cpuidle-psci.c
> > index 2562dc001fc1..dd8d776d6e39 100644
> > --- a/drivers/cpuidle/cpuidle-psci.c
> > +++ b/drivers/cpuidle/cpuidle-psci.c
> > @@ -25,6 +25,7 @@
> >  #include <linux/syscore_ops.h>
> >
> >  #include <asm/cpuidle.h>
> > +#include <trace/events/power.h>
> >
> >  #include "cpuidle-psci.h"
> >  #include "dt_idle_states.h"
> > @@ -74,7 +75,9 @@ static __cpuidle int __psci_enter_domain_idle_state(struct cpuidle_device *dev,
> >  	if (!state)
> >  		state = states[idx];
> >
> > +	trace_psci_domain_idle_enter(dev->cpu, state, s2idle);
> >  	ret = psci_cpu_suspend_enter(state) ? -1 : idx;
> > +	trace_psci_domain_idle_exit(dev->cpu, state, s2idle);
> Not tracking ret seems odd, is that fine?

I think it's fine not to track ret here.
__psci_enter_domain_idle_state does not seems to care the return value of
psci_cpu_suspend_enter to me because it just proceeds with executing subsequent
functions regardless of ret, and returns ret to the higher function. If the
value should be traced, it should probably be done in a lower layer or a higher
layer.

Another small small reason I'm not interested in adding ret to the
trace_psci_domain_idle_exit's arguments is that
trace_psci_domain_idle_(enter|exit) currently share the same trace event
(i.e. same set of arguments) and it makes the trace events simple.
Re: [PATCH v2] cpuidle: psci: Add trace for PSCI domain idle
Posted by Christian Loehle 1 year ago 
On 1/28/25 04:24, Keita Morisaki wrote:
>>> The trace event cpu_idle provides insufficient information for debugging
>>> PSCI requests due to lacking access to determined PSCI domain idle
>>> states. The cpu_idle usually only shows -1, 0, or 1 regardless how many
>>> idle states the power domain has.
>>>
>>> Add new trace events namely psci_domain_idle_enter and
>>> psci_domain_idle_exit to trace enter and exit events with a determined
>>> idle state.
>>>
>>> These new trace events will help developers debug CPUidle issues on ARM
>>> systems using PSCI by providing more detailed information about the
>>> requested idle states.
>>>
>>> Signed-off-by: Keita Morisaki <keyz@google.com>
>>> ---
>>> v1->v2: Split the ftrace event into two (psci_domain_idle_(enter|exit))
>>> 		and rephrase the commit message accordingly. Rebased onto the latest.
>> Which makes it different to cpu_idle event FWIW.
> 
> Yes, psci_domain_idle_(enter|exit) are not meant to replace cpu_idle nor a
> variant of it. It's new and different events that provide finer=grained info.
> 

I mentioned it because it means it doesn't benefit from cpu_idle tooling
directly, which is slightly odd, but fine with me.
Re: [PATCH v2] cpuidle: psci: Add trace for PSCI domain idle
Posted by Keita Morisaki 1 year ago 
> > Yes, psci_domain_idle_(enter|exit) are not meant to replace cpu_idle nor a
> > variant of it. It's new and different events that provide finer=grained info.

> I mentioned it because it means it doesn't benefit from cpu_idle tooling
> directly, which is slightly odd, but fine with me.

I might not fully understand your comments.
Do you mean that even mentioning cpu_idle in the commit message does not feel
right to you, or utilizing cpu_idle by exposing the determined state instead of
adding new trace events is the right direction?
Re: [PATCH v2] cpuidle: psci: Add trace for PSCI domain idle
Posted by Steven Rostedt 1 year ago 
On Mon, 20 Jan 2025 09:36:16 +0800
Keita Morisaki <keyz@google.com> wrote:

> The trace event cpu_idle provides insufficient information for debugging
> PSCI requests due to lacking access to determined PSCI domain idle
> states. The cpu_idle usually only shows -1, 0, or 1 regardless how many
> idle states the power domain has.
> 
> Add new trace events namely psci_domain_idle_enter and
> psci_domain_idle_exit to trace enter and exit events with a determined
> idle state.
> 
> These new trace events will help developers debug CPUidle issues on ARM
> systems using PSCI by providing more detailed information about the
> requested idle states.
> 
> Signed-off-by: Keita Morisaki <keyz@google.com>
> ---
> v1->v2: Split the ftrace event into two (psci_domain_idle_(enter|exit))
> 		and rephrase the commit message accordingly. Rebased onto the latest.
> 
>  drivers/cpuidle/cpuidle-psci.c |  3 +++
>  include/trace/events/power.h   | 37 ++++++++++++++++++++++++++++++++++
>  2 files changed, 40 insertions(+)

From the tracing point of view, there's nothing that sticks out that is incorrect.

Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org>

As for if it should be applied, that's for the maintainers of the subsystem
that it exists in.

-- Steve
Re: [PATCH v2] cpuidle: psci: Add trace for PSCI domain idle
Posted by Keita Morisaki 1 year ago 
> Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org>

> As for if it should be applied, that's for the maintainers of the subsystem
> that it exists in.

Thank you so much!
[PATCH v3] cpuidle: psci: Add trace for PSCI domain idle
Posted by Keita Morisaki 1 year ago 
The trace event cpu_idle provides insufficient information for debugging
PSCI requests due to lacking access to determined PSCI domain idle
states. The cpu_idle usually only shows -1, 0, or 1 regardless how many
idle states the power domain has.

Add new trace events namely psci_domain_idle_enter and
psci_domain_idle_exit to trace enter and exit events with a determined
idle state.

These new trace events will help developers debug CPUidle issues on ARM
systems using PSCI by providing more detailed information about the
requested idle states.

Signed-off-by: Keita Morisaki <keyz@google.com>
Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org>
---
v1->v2: Split the ftrace event into two (psci_domain_idle_(enter|exit))
        and rephrase the commit message accordingly. Rebased onto the latest.
v2->v3: Add the Reviewed-by label

 drivers/cpuidle/cpuidle-psci.c |  3 +++
 include/trace/events/power.h   | 37 ++++++++++++++++++++++++++++++++++
 2 files changed, 40 insertions(+)

diff --git a/drivers/cpuidle/cpuidle-psci.c b/drivers/cpuidle/cpuidle-psci.c
index 2562dc001fc1..dd8d776d6e39 100644
--- a/drivers/cpuidle/cpuidle-psci.c
+++ b/drivers/cpuidle/cpuidle-psci.c
@@ -25,6 +25,7 @@
 #include <linux/syscore_ops.h>

 #include <asm/cpuidle.h>
+#include <trace/events/power.h>

 #include "cpuidle-psci.h"
 #include "dt_idle_states.h"
@@ -74,7 +75,9 @@ static __cpuidle int __psci_enter_domain_idle_state(struct cpuidle_device *dev,
 	if (!state)
 		state = states[idx];

+	trace_psci_domain_idle_enter(dev->cpu, state, s2idle);
 	ret = psci_cpu_suspend_enter(state) ? -1 : idx;
+	trace_psci_domain_idle_exit(dev->cpu, state, s2idle);

 	if (s2idle)
 		dev_pm_genpd_resume(pd_dev);
diff --git a/include/trace/events/power.h b/include/trace/events/power.h
index d2349b6b531a..9253e83b9bb4 100644
--- a/include/trace/events/power.h
+++ b/include/trace/events/power.h
@@ -62,6 +62,43 @@ TRACE_EVENT(cpu_idle_miss,
 		(unsigned long)__entry->state, (__entry->below)?"below":"above")
 );

+DECLARE_EVENT_CLASS(psci_domain_idle,
+
+	TP_PROTO(unsigned int cpu_id, unsigned int state, bool s2idle),
+
+	TP_ARGS(cpu_id, state, s2idle),
+
+	TP_STRUCT__entry(
+		__field(u32,		cpu_id)
+		__field(u32,		state)
+		__field(bool,		s2idle)
+	),
+
+	TP_fast_assign(
+		__entry->cpu_id = cpu_id;
+		__entry->state = state;
+		__entry->s2idle = s2idle;
+	),
+
+	TP_printk("cpu_id=%lu state=0x%lx is_s2idle=%s",
+		  (unsigned long)__entry->cpu_id, (unsigned long)__entry->state,
+		  (__entry->s2idle)?"yes":"no")
+);
+
+DEFINE_EVENT(psci_domain_idle, psci_domain_idle_enter,
+
+	TP_PROTO(unsigned int cpu_id, unsigned int state, bool s2idle),
+
+	TP_ARGS(cpu_id, state, s2idle)
+);
+
+DEFINE_EVENT(psci_domain_idle, psci_domain_idle_exit,
+
+	TP_PROTO(unsigned int cpu_id, unsigned int state, bool s2idle),
+
+	TP_ARGS(cpu_id, state, s2idle)
+);
+
 TRACE_EVENT(powernv_throttle,

 	TP_PROTO(int chip_id, const char *reason, int pmax),

base-commit: ffd294d346d185b70e28b1a28abe367bbfe53c04
--
2.48.1.262.g85cc9f2d1e-goog
Re: [PATCH v3] cpuidle: psci: Add trace for PSCI domain idle
Posted by Kevin Hilman 1 year ago 
Keita Morisaki <keyz@google.com> writes:

> The trace event cpu_idle provides insufficient information for debugging
> PSCI requests due to lacking access to determined PSCI domain idle
> states. The cpu_idle usually only shows -1, 0, or 1 regardless how many
> idle states the power domain has.
>
> Add new trace events namely psci_domain_idle_enter and
> psci_domain_idle_exit to trace enter and exit events with a determined
> idle state.
>
> These new trace events will help developers debug CPUidle issues on ARM
> systems using PSCI by providing more detailed information about the
> requested idle states.
>
> Signed-off-by: Keita Morisaki <keyz@google.com>
> Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org>

Tested-by: Kevin Hilman <khilman@baylibre.com>

I've been using some local trace_printk() to do exactly this, so I fully
support having some official tracepoints here. 

For my local hacks, I was trackin the state index as well as the state
value since for quick debug, I find the index to more human readable
than the state value, which I have to compare with the
arm,psci-suspend-pararm from the DT.

Anyways, thanks for submitting this!

Kevin
Re: [PATCH v3] cpuidle: psci: Add trace for PSCI domain idle
Posted by Keita Morisaki 1 year ago 
> Tested-by: Kevin Hilman <khilman@baylibre.com>
>
> I've been using some local trace_printk() to do exactly this, so I fully
> support having some official tracepoints here.
>
> For my local hacks, I was trackin the state index as well as the state
> value since for quick debug, I find the index to more human readable
> than the state value, which I have to compare with the
> arm,psci-suspend-pararm from the DT.
>
> Anyways, thanks for submitting this!
>
> Kevin

Thank you so much for the endorsement.
Showing the index sounds like a good idea, although it should be done in a
different layer (probably in the GenPD governor or cpuidle-psci driver?) because
idx here should be the different index from the one we're looking for.
I will keep my patch as it is just for now. Thank you for the idea!
[PATCH v4] cpuidle: psci: Add trace for PSCI domain idle
Posted by Keita Morisaki 1 year ago 
The trace event cpu_idle provides insufficient information for debugging
PSCI requests due to lacking access to determined PSCI domain idle
states. The cpu_idle usually only shows -1, 0, or 1 regardless how many
idle states the power domain has.

Add new trace events namely psci_domain_idle_enter and
psci_domain_idle_exit to trace enter and exit events with a determined
idle state.

These new trace events will help developers debug CPUidle issues on ARM
systems using PSCI by providing more detailed information about the
requested idle states.

Signed-off-by: Keita Morisaki <keyz@google.com>
Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Tested-by: Kevin Hilman <khilman@baylibre.com>
---
v1->v2: Split the ftrace event into two (psci_domain_idle_(enter|exit))
        and rephrase the commit message accordingly. Rebased onto the latest.
v2->v3: Add the Reviewed-by label
v3->v4: Add the Tested-by label

 drivers/cpuidle/cpuidle-psci.c |  3 +++
 include/trace/events/power.h   | 37 ++++++++++++++++++++++++++++++++++
 2 files changed, 40 insertions(+)

diff --git a/drivers/cpuidle/cpuidle-psci.c b/drivers/cpuidle/cpuidle-psci.c
index 2562dc001fc1..dd8d776d6e39 100644
--- a/drivers/cpuidle/cpuidle-psci.c
+++ b/drivers/cpuidle/cpuidle-psci.c
@@ -25,6 +25,7 @@
 #include <linux/syscore_ops.h>

 #include <asm/cpuidle.h>
+#include <trace/events/power.h>

 #include "cpuidle-psci.h"
 #include "dt_idle_states.h"
@@ -74,7 +75,9 @@ static __cpuidle int __psci_enter_domain_idle_state(struct cpuidle_device *dev,
 	if (!state)
 		state = states[idx];

+	trace_psci_domain_idle_enter(dev->cpu, state, s2idle);
 	ret = psci_cpu_suspend_enter(state) ? -1 : idx;
+	trace_psci_domain_idle_exit(dev->cpu, state, s2idle);

 	if (s2idle)
 		dev_pm_genpd_resume(pd_dev);
diff --git a/include/trace/events/power.h b/include/trace/events/power.h
index d2349b6b531a..9253e83b9bb4 100644
--- a/include/trace/events/power.h
+++ b/include/trace/events/power.h
@@ -62,6 +62,43 @@ TRACE_EVENT(cpu_idle_miss,
 		(unsigned long)__entry->state, (__entry->below)?"below":"above")
 );

+DECLARE_EVENT_CLASS(psci_domain_idle,
+
+	TP_PROTO(unsigned int cpu_id, unsigned int state, bool s2idle),
+
+	TP_ARGS(cpu_id, state, s2idle),
+
+	TP_STRUCT__entry(
+		__field(u32,		cpu_id)
+		__field(u32,		state)
+		__field(bool,		s2idle)
+	),
+
+	TP_fast_assign(
+		__entry->cpu_id = cpu_id;
+		__entry->state = state;
+		__entry->s2idle = s2idle;
+	),
+
+	TP_printk("cpu_id=%lu state=0x%lx is_s2idle=%s",
+		  (unsigned long)__entry->cpu_id, (unsigned long)__entry->state,
+		  (__entry->s2idle)?"yes":"no")
+);
+
+DEFINE_EVENT(psci_domain_idle, psci_domain_idle_enter,
+
+	TP_PROTO(unsigned int cpu_id, unsigned int state, bool s2idle),
+
+	TP_ARGS(cpu_id, state, s2idle)
+);
+
+DEFINE_EVENT(psci_domain_idle, psci_domain_idle_exit,
+
+	TP_PROTO(unsigned int cpu_id, unsigned int state, bool s2idle),
+
+	TP_ARGS(cpu_id, state, s2idle)
+);
+
 TRACE_EVENT(powernv_throttle,

 	TP_PROTO(int chip_id, const char *reason, int pmax),

base-commit: ffd294d346d185b70e28b1a28abe367bbfe53c04
--
2.48.1.362.g079036d154-goog
Re: [PATCH v4] cpuidle: psci: Add trace for PSCI domain idle
Posted by Dhruva Gole 1 year ago 
Hi Keita,

On Feb 02, 2025 at 18:46:08 +0800, Keita Morisaki wrote:
> The trace event cpu_idle provides insufficient information for debugging
> PSCI requests due to lacking access to determined PSCI domain idle
> states. The cpu_idle usually only shows -1, 0, or 1 regardless how many
> idle states the power domain has.
> 
> Add new trace events namely psci_domain_idle_enter and
> psci_domain_idle_exit to trace enter and exit events with a determined
> idle state.

Thanks for this, will really ease those psci idle debugs for everyone!

> 
> These new trace events will help developers debug CPUidle issues on ARM
> systems using PSCI by providing more detailed information about the
> requested idle states.
> 
> Signed-off-by: Keita Morisaki <keyz@google.com>
> Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org>
> Tested-by: Kevin Hilman <khilman@baylibre.com>

Reviewed-by: Dhruva Gole <d-gole@ti.com>


-- 
Best regards,
Dhruva Gole
Texas Instruments Incorporated

Patchew 2.1-devel-b67e4c2

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