Re: [PATCH] PM: trace events for suspend/resume

[Todd E Brandt <todd.e.brandt@linux.intel.com>]

On Thu, May 22, 2014 at 02:01:44AM +0200, Rafael J. Wysocki wrote:
> On Monday, May 19, 2014 04:02:26 PM Todd E Brandt wrote:
> > Adds trace events that give finer resolution into suspend/resume. These
> > events are graphed in the timelines generated by the analyze_suspend.py
> > script. They represent large areas of time consumed that are typical in
> > suspend and resume.
> > 
> > The event is triggered by calling the function "trace_suspend_resume"
> > with two arguments: a string (the name of the event to be displayed
> > in the timeline), and a boolean (where true is used to denote the start
> > of the timeline event, and false to denote the end).
> > 
> > Signed-off-by: Todd Brandt <todd.e.brandt@intel.com>
> > ---
> >  drivers/acpi/nvs.c           |  6 ++++++
> >  drivers/acpi/osl.c           |  3 +++
> >  drivers/base/syscore.c       |  5 +++++
> >  include/trace/events/power.h | 19 +++++++++++++++++++
> >  kernel/cpu.c                 |  9 +++++++++
> >  kernel/power/process.c       |  3 +++
> >  kernel/power/suspend.c       |  4 ++++
> >  7 files changed, 49 insertions(+)
> > 
> > For more info see:
> > https://01.org/suspendresume/blogs/tebrandt/2014/custom-timeline-event-support-0
> > 
> > I'm also interested to know if any tools depend on the machine_suspend
> > tracepoints, as this patch expands on the same info. I'd be willing to
> > merge the existing machine_suspend calls into this patch and rename
> > everything to suspend_resume provided it doesn't hurt any downstream tools.
> > 
> > diff --git a/drivers/acpi/nvs.c b/drivers/acpi/nvs.c
> > index de4fe03..b52b686 100644
> > --- a/drivers/acpi/nvs.c
> > +++ b/drivers/acpi/nvs.c
> > @@ -12,6 +12,7 @@
> >  #include <linux/mm.h>
> >  #include <linux/slab.h>
> >  #include <linux/acpi.h>
> > +#include <trace/events/power.h>
> >  
> >  #include "internal.h"
> >  
> > @@ -171,6 +172,7 @@ int suspend_nvs_save(void)
> >  {
> >  	struct nvs_page *entry;
> >  
> > +	trace_suspend_resume("save_nvs_memory", true);
> >  	printk(KERN_INFO "PM: Saving platform NVS memory\n");
> >  
> >  	list_for_each_entry(entry, &nvs_list, node)
> > @@ -185,11 +187,13 @@ int suspend_nvs_save(void)
> >  			}
> >  			if (!entry->kaddr) {
> >  				suspend_nvs_free();
> > +				trace_suspend_resume("save_nvs_memory", false);
> >  				return -ENOMEM;
> >  			}
> >  			memcpy(entry->data, entry->kaddr, entry->size);
> >  		}
> >  
> > +	trace_suspend_resume("save_nvs_memory", false);
> >  	return 0;
> >  }
> >  
> > @@ -203,10 +207,12 @@ void suspend_nvs_restore(void)
> >  {
> >  	struct nvs_page *entry;
> >  
> > +	trace_suspend_resume("restore_nvs_memory", true);
> >  	printk(KERN_INFO "PM: Restoring platform NVS memory\n");
> >  
> >  	list_for_each_entry(entry, &nvs_list, node)
> >  		if (entry->data)
> >  			memcpy(entry->kaddr, entry->data, entry->size);
> > +	trace_suspend_resume("restore_nvs_memory", false);
> >  }
> >  #endif
> > diff --git a/drivers/acpi/osl.c b/drivers/acpi/osl.c
> > index 6776c59..b65a77a 100644
> > --- a/drivers/acpi/osl.c
> > +++ b/drivers/acpi/osl.c
> > @@ -44,6 +44,7 @@
> >  #include <linux/list.h>
> >  #include <linux/jiffies.h>
> >  #include <linux/semaphore.h>
> > +#include <trace/events/power.h>
> >  
> >  #include <asm/io.h>
> >  #include <asm/uaccess.h>
> > @@ -835,7 +836,9 @@ acpi_status acpi_os_remove_interrupt_handler(u32 irq, acpi_osd_handler handler)
> >  
> >  void acpi_os_sleep(u64 ms)
> >  {
> > +	trace_suspend_resume("acpi_os_sleep", true);
> >  	msleep(ms);
> > +	trace_suspend_resume("acpi_os_sleep", false);
> >  }
> 
> This function doesn't have anything to do with system suspend/resume.
> It is for waiting. :-)

Yea but it really helps you diagnose bad firmware during suspend/resume
(for instance when there's just an arbitrary sleep 100ms in the ACPI code).
But it doesn't matter for general performance testing, I'll remove it on v2
submit.

> 
> The rest of the patch looks OK to me.
> 
> Steven, what about the tracing angle?
> 
> >  
> >  void acpi_os_stall(u32 us)
> > diff --git a/drivers/base/syscore.c b/drivers/base/syscore.c
> > index e8d11b6..c2fd5d4 100644
> > --- a/drivers/base/syscore.c
> > +++ b/drivers/base/syscore.c
> > @@ -10,6 +10,7 @@
> >  #include <linux/mutex.h>
> >  #include <linux/module.h>
> >  #include <linux/interrupt.h>
> > +#include <trace/events/power.h>
> >  
> >  static LIST_HEAD(syscore_ops_list);
> >  static DEFINE_MUTEX(syscore_ops_lock);
> > @@ -49,6 +50,7 @@ int syscore_suspend(void)
> >  	struct syscore_ops *ops;
> >  	int ret = 0;
> >  
> > +	trace_suspend_resume("syscore_suspend", true);
> >  	pr_debug("Checking wakeup interrupts\n");
> >  
> >  	/* Return error code if there are any wakeup interrupts pending. */
> > @@ -70,6 +72,7 @@ int syscore_suspend(void)
> >  				"Interrupts enabled after %pF\n", ops->suspend);
> >  		}
> >  
> > +	trace_suspend_resume("syscore_suspend", false);
> >  	return 0;
> >  
> >   err_out:
> > @@ -92,6 +95,7 @@ void syscore_resume(void)
> >  {
> >  	struct syscore_ops *ops;
> >  
> > +	trace_suspend_resume("syscore_resume", true);
> >  	WARN_ONCE(!irqs_disabled(),
> >  		"Interrupts enabled before system core resume.\n");
> >  
> > @@ -103,6 +107,7 @@ void syscore_resume(void)
> >  			WARN_ONCE(!irqs_disabled(),
> >  				"Interrupts enabled after %pF\n", ops->resume);
> >  		}
> > +	trace_suspend_resume("syscore_resume", false);
> >  }
> >  EXPORT_SYMBOL_GPL(syscore_resume);
> >  #endif /* CONFIG_PM_SLEEP */
> > diff --git a/include/trace/events/power.h b/include/trace/events/power.h
> > index 9a7e08d..1d9fd76 100644
> > --- a/include/trace/events/power.h
> > +++ b/include/trace/events/power.h
> > @@ -151,6 +151,25 @@ TRACE_EVENT(device_pm_report_time,
> >  		__entry->ops_time, __entry->error)
> >  );
> >  
> > +TRACE_EVENT(suspend_resume,
> > +
> > +	TP_PROTO(char *action, bool start),
> > +
> > +	TP_ARGS(action, start),
> > +
> > +	TP_STRUCT__entry(
> > +		__string(action, action)
> > +		__field(bool, start)
> > +	),
> > +
> > +	TP_fast_assign(
> > +		__assign_str(action, action);
> > +		__entry->start = start;
> > +	),
> > +
> > +	TP_printk("%s %s", __get_str(action), (__entry->start)?"begin":"end")
> > +);
> > +
> >  DECLARE_EVENT_CLASS(wakeup_source,
> >  
> >  	TP_PROTO(const char *name, unsigned int state),
> > diff --git a/kernel/cpu.c b/kernel/cpu.c
> > index a9e710e..7aa30ec 100644
> > --- a/kernel/cpu.c
> > +++ b/kernel/cpu.c
> > @@ -20,6 +20,7 @@
> >  #include <linux/gfp.h>
> >  #include <linux/suspend.h>
> >  #include <linux/lockdep.h>
> > +#include <trace/events/power.h>
> >  
> >  #include "smpboot.h"
> >  
> > @@ -509,6 +510,7 @@ static cpumask_var_t frozen_cpus;
> >  int disable_nonboot_cpus(void)
> >  {
> >  	int cpu, first_cpu, error = 0;
> > +	char buf[12];
> >  
> >  	cpu_maps_update_begin();
> >  	first_cpu = cpumask_first(cpu_online_mask);
> > @@ -522,7 +524,10 @@ int disable_nonboot_cpus(void)
> >  	for_each_online_cpu(cpu) {
> >  		if (cpu == first_cpu)
> >  			continue;
> > +		sprintf(buf, "CPU%u_OFF", cpu);
> > +		trace_suspend_resume(buf, true);
> >  		error = _cpu_down(cpu, 1);
> > +		trace_suspend_resume(buf, false);
> >  		if (!error)
> >  			cpumask_set_cpu(cpu, frozen_cpus);
> >  		else {
> > @@ -554,6 +559,7 @@ void __weak arch_enable_nonboot_cpus_end(void)
> >  void __ref enable_nonboot_cpus(void)
> >  {
> >  	int cpu, error;
> > +	char buf[10];
> >  
> >  	/* Allow everyone to use the CPU hotplug again */
> >  	cpu_maps_update_begin();
> > @@ -566,7 +572,10 @@ void __ref enable_nonboot_cpus(void)
> >  	arch_enable_nonboot_cpus_begin();
> >  
> >  	for_each_cpu(cpu, frozen_cpus) {
> > +		sprintf(buf, "CPU%u_ON", cpu);
> > +		trace_suspend_resume(buf, true);
> >  		error = _cpu_up(cpu, 1);
> > +		trace_suspend_resume(buf, false);
> >  		if (!error) {
> >  			printk(KERN_INFO "CPU%d is up\n", cpu);
> >  			continue;
> > diff --git a/kernel/power/process.c b/kernel/power/process.c
> > index 06ec886..4aec2d9 100644
> > --- a/kernel/power/process.c
> > +++ b/kernel/power/process.c
> > @@ -17,6 +17,7 @@
> >  #include <linux/delay.h>
> >  #include <linux/workqueue.h>
> >  #include <linux/kmod.h>
> > +#include <trace/events/power.h>
> >  
> >  /* 
> >   * Timeout for stopping processes
> > @@ -175,6 +176,7 @@ void thaw_processes(void)
> >  	struct task_struct *g, *p;
> >  	struct task_struct *curr = current;
> >  
> > +	trace_suspend_resume("thaw_processes", true);
> >  	if (pm_freezing)
> >  		atomic_dec(&system_freezing_cnt);
> >  	pm_freezing = false;
> > @@ -201,6 +203,7 @@ void thaw_processes(void)
> >  
> >  	schedule();
> >  	printk("done.\n");
> > +	trace_suspend_resume("thaw_processes", false);
> >  }
> >  
> >  void thaw_kernel_threads(void)
> > diff --git a/kernel/power/suspend.c b/kernel/power/suspend.c
> > index 8233cd4..c7e3e9f 100644
> > --- a/kernel/power/suspend.c
> > +++ b/kernel/power/suspend.c
> > @@ -147,7 +147,9 @@ static int suspend_prepare(suspend_state_t state)
> >  	if (error)
> >  		goto Finish;
> >  
> > +	trace_suspend_resume("freeze_processes", true);
> >  	error = suspend_freeze_processes();
> > +	trace_suspend_resume("freeze_processes", false);
> >  	if (!error)
> >  		return 0;
> >  
> > @@ -337,9 +339,11 @@ static int enter_state(suspend_state_t state)
> >  	if (state == PM_SUSPEND_FREEZE)
> >  		freeze_begin();
> >  
> > +	trace_suspend_resume("sync_filesystems", true);
> >  	printk(KERN_INFO "PM: Syncing filesystems ... ");
> >  	sys_sync();
> >  	printk("done.\n");
> > +	trace_suspend_resume("sync_filesystems", false);
> >  
> >  	pr_debug("PM: Preparing system for %s sleep\n", pm_states[state]);
> >  	error = suspend_prepare(state);
> > --
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> 
> -- 
> I speak only for myself.
> Rafael J. Wysocki, Intel Open Source Technology Center.