| Message ID | 20250120013616.1116126-1-keyz@google.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | [v2] cpuidle: psci: Add trace for PSCI domain idle | expand |
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
> 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!
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?
> > 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.
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.
> > 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?
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),
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(+) base-commit: ffd294d346d185b70e28b1a28abe367bbfe53c04 -- 2.48.0.rc2.279.g1de40edade-goog