trace: osnoise tracer fixes

PATCH New Daniel Bristot de Oliveira 1 participant 5 messages Jun 28, 2021

Subsystems (4)

Documentation x86 Tracing Tracing OS noise / latency tracers

lore

Share & tools

lore

Daniel Bristot de Oliveira

author

2021-06-28 09:46 UTC #0 lore raw

cover trace: osnoise tracer fixes

Fixes problems reported by kernel test robot <[email protected]>, and a typo in the documentation.

No functional change.

Daniel Bristot de Oliveira (4):
trace/osnoise: Fix 'no previous prototype' warnings trace/osnoise: Make interval u64 on osnoise_main trace/osnoise: Fix return value on osnoise_init_hotplug_support
Documentation: Fix a typo on trace/osnoise-tracer

 Documentation/trace/osnoise-tracer.rst |  2 +-
 arch/x86/kernel/trace.c                |  3 ---
 include/linux/trace.h                  |  2 ++
 kernel/trace/trace_osnoise.c           | 24 +++++++++++++-----------
 4 files changed, 16 insertions(+), 15 deletions(-)

Signature · 1 line

2.31.1

Daniel Bristot de Oliveira

author

2021-06-28 09:46 UTC #1 lore raw

PATCH 1/4 trace/osnoise: Fix 'no previous prototype' warnings

kernel test robot reported some osnoise functions with "no previous prototype."

Fix these warnings by making local functions static, and by adding:

void osnoise_trace_irq_entry(int id);
void osnoise_trace_irq_exit(int id, const char *desc);

to include/linux/trace.h.

Fixes bce29ac9ce0b ("trace: Add osnoise tracer")

Reported-by kernel test robot <[email protected]>

Signed-off-by Daniel Bristot de Oliveira <[email protected]>

---
 arch/x86/kernel/trace.c      |  3 ---
 include/linux/trace.h        |  2 ++
 kernel/trace/trace_osnoise.c | 20 +++++++++++---------
 3 files changed, 13 insertions(+), 12 deletions(-)

arch/x86/kernel/trace.c +0 -3

index 6912672c33a7..6b73b6f92ad3 100644
@@ -2,9 +2,6 @@
 #include <linux/trace.h>
 
 #if defined(CONFIG_OSNOISE_TRACER) && defined(CONFIG_X86_LOCAL_APIC)
-extern void osnoise_trace_irq_entry(int id);
-extern void osnoise_trace_irq_exit(int id, const char *desc);
-
 /*
  * trace_intel_irq_entry - record intel specific IRQ entry
  */

include/linux/trace.h +2 -0

index 4e3858640c47..bf169612ffe1 100644
@@ -45,6 +45,8 @@ int trace_array_destroy(struct trace_array *tr);
 /* For osnoise tracer */
 int osnoise_arch_register(void);
 void osnoise_arch_unregister(void);
+void osnoise_trace_irq_entry(int id);
+void osnoise_trace_irq_exit(int id, const char *desc);
 
 #endif	/* CONFIG_TRACING */

kernel/trace/trace_osnoise.c +11 -9

index 38aa5e208ffd..e2401659b0e5 100644
@@ -736,7 +736,7 @@ void __weak osnoise_arch_unregister(void)
  * This function hooks the IRQ related callbacks to the respective trace
  * events.
  */
-int hook_irq_events(void)
+static int hook_irq_events(void)
 {
 	int ret;

@@ -768,7 +768,7 @@ int hook_irq_events(void)
  * This function unhooks the IRQ related callbacks to the respective trace
  * events.
  */
-void unhook_irq_events(void)
+static void unhook_irq_events(void)
 {
 	osnoise_arch_unregister();
 	unregister_trace_irq_handler_exit(trace_irqexit_callback, NULL);

@@ -785,7 +785,7 @@ void unhook_irq_events(void)
  * arrival time. The delta_start is used to compute the duration at the
  * softirq exit handler. See cond_move_softirq_delta_start().
  */
-void trace_softirq_entry_callback(void *data, unsigned int vec_nr)
+static void trace_softirq_entry_callback(void *data, unsigned int vec_nr)
 {
 	struct osnoise_variables *osn_var = this_cpu_osn_var();

@@ -808,7 +808,7 @@ void trace_softirq_entry_callback(void *data, unsigned int vec_nr)
  * Computes the duration of the softirq noise, and trace it. Also discounts the
  * interference from other sources of noise could be currently being accounted.
  */
-void trace_softirq_exit_callback(void *data, unsigned int vec_nr)
+static void trace_softirq_exit_callback(void *data, unsigned int vec_nr)
 {
 	struct osnoise_variables *osn_var = this_cpu_osn_var();
 	int duration;

@@ -949,7 +949,7 @@ thread_exit(struct osnoise_variables *osn_var, struct task_struct *t)
  * This function is hooked to the sched:sched_switch trace event, and it is
  * used to record the beginning and to report the end of a thread noise window.
  */
-void
+static void
 trace_sched_switch_callback(void *data, bool preempt, struct task_struct *p,
 			    struct task_struct *n)
 {

@@ -968,7 +968,7 @@ trace_sched_switch_callback(void *data, bool preempt, struct task_struct *p,
  * Hook the osnoise tracer callbacks to handle the noise from other
  * threads on the necessary kernel events.
  */
-int hook_thread_events(void)
+static int hook_thread_events(void)
 {
 	int ret;

@@ -985,7 +985,7 @@ int hook_thread_events(void)
  * Unook the osnoise tracer callbacks to handle the noise from other
  * threads on the necessary kernel events.
  */
-void unhook_thread_events(void)
+static void unhook_thread_events(void)
 {
 	unregister_trace_sched_switch(trace_sched_switch_callback, NULL);
 }

@@ -997,7 +997,8 @@ void unhook_thread_events(void)
  * values will be used later to compute the diff betwneen the statistics
  * before and after the osnoise sampling.
  */
-void save_osn_sample_stats(struct osnoise_variables *osn_var, struct osnoise_sample *s)
+static void
+save_osn_sample_stats(struct osnoise_variables *osn_var, struct osnoise_sample *s)
 {
 	s->nmi_count = osn_var->nmi.count;
 	s->irq_count = osn_var->irq.count;

@@ -1012,7 +1013,8 @@ void save_osn_sample_stats(struct osnoise_variables *osn_var, struct osnoise_sam
  * statistics. The struct osnoise_sample *s contains the statistics saved via
  * save_osn_sample_stats() before the osnoise sampling.
  */
-void diff_osn_sample_stats(struct osnoise_variables *osn_var, struct osnoise_sample *s)
+static void
+diff_osn_sample_stats(struct osnoise_variables *osn_var, struct osnoise_sample *s)
 {
 	s->nmi_count = osn_var->nmi.count - s->nmi_count;
 	s->irq_count = osn_var->irq.count - s->irq_count;

Signature · 1 line

2.31.1

Daniel Bristot de Oliveira

author

2021-06-28 09:47 UTC #2 lore raw

PATCH 2/4 trace/osnoise: Make interval u64 on osnoise_main

In reply to Daniel Bristot de Oliveira

kernel test robot reported:

Quoted 1 line

Quoted 1 line
kernel/trace/trace_osnoise.c:966:3: warning: comparison of distinct

     pointer types ('typeof ((interval)) *' (aka 'long long *') and
     'uint64_t *' (aka 'unsigned long long *'))
     [-Wcompare-distinct-pointer-types]
                   do_div(interval, USEC_PER_MSEC);
                   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   include/asm-generic/div64.h:228:28: note: expanded from macro 'do_div'
           (void)(((typeof((n)) *)0) == ((uint64_t *)0));  \
                  ~~~~~~~~~~~~~~~~~~ ^  ~~~~~~~~~~~~~~~

As interval cannot be negative because sample_period >= sample_runtime, making interval u64 on osnoise_main() is enough to fix this problem.

Fixes bce29ac9ce0b ("trace: Add osnoise tracer")

Reported-by kernel test robot <[email protected]>

Signed-off-by Daniel Bristot de Oliveira <[email protected]>

---
 kernel/trace/trace_osnoise.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

kernel/trace/trace_osnoise.c +1 -1

index e2401659b0e5..4cd9e66e8513 100644
@@ -1202,7 +1202,7 @@ static struct cpumask save_cpumask;
  */
 static int osnoise_main(void *data)
 {
-	s64 interval;
+	u64 interval;
 
 	while (!kthread_should_stop()) {

Signature · 1 line

2.31.1

Daniel Bristot de Oliveira

author

2021-06-28 09:47 UTC #3 lore raw

PATCH 3/4 trace/osnoise: Fix return value on osnoise_init_hotplug_support

In reply to Daniel Bristot de Oliveira

kernel test robot reported:

Quoted 1 line

Quoted 1 line
kernel/trace/trace_osnoise.c:1584:2: error: void function

'osnoise_init_hotplug_support' should not return a value [-Wreturn-type]

           return 0;

When !CONFIG_HOTPLUG_CPU.

Fix it problem by removing the return value.

Fixes c8895e271f79 ("trace/osnoise: Support hotplug operations")

Reported-by kernel test robot <[email protected]>

Signed-off-by Daniel Bristot de Oliveira <[email protected]>

---
 kernel/trace/trace_osnoise.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

kernel/trace/trace_osnoise.c +1 -1

index 4cd9e66e8513..03d41cb2219f 100644
@@ -1583,7 +1583,7 @@ static void osnoise_init_hotplug_support(void)
 #else /* CONFIG_HOTPLUG_CPU */
 static void osnoise_init_hotplug_support(void)
 {
-	return 0;
+	return;
 }
 #endif /* CONFIG_HOTPLUG_CPU */

Signature · 1 line

2.31.1

Daniel Bristot de Oliveira

author

2021-06-28 09:47 UTC #4 lore raw

PATCH 4/4 Documentation: Fix a typo on trace/osnoise-tracer

In reply to Daniel Bristot de Oliveira

s/RUNTIME IN USE/RUNTIME IN US/

Fixes bce29ac9ce0b ("trace: Add osnoise tracer")

Signed-off-by Daniel Bristot de Oliveira <[email protected]>

---
 Documentation/trace/osnoise-tracer.rst | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Documentation/trace/osnoise-tracer.rst +1 -1

index 37a3c10fb216..b648cb9bf1f0 100644
@@ -77,7 +77,7 @@ In addition to the regular trace fields (from TASK-PID to TIMESTAMP), the
 tracer prints a message at the end of each period for each CPU that is
 running an osnoise/ thread. The osnoise specific fields report:
 
- - The RUNTIME IN USE reports the amount of time in microseconds that
+ - The RUNTIME IN US reports the amount of time in microseconds that
    the osnoise thread kept looping reading the time.
  - The NOISE IN US reports the sum of noise in microseconds observed
    by the osnoise tracer during the associated runtime.

Signature · 1 line

2.31.1