This is useful to check for any improvements or degradation related to
number of GP kthread wakeups during testing.
Signed-off-by: Joel Fernandes (Google) <[email protected]>
---
kernel/rcu/Kconfig.debug | 1 +
kernel/rcu/rcu.h | 2 ++
kernel/rcu/rcutorture.c | 23 ++++++++++++++++++++++-
kernel/rcu/tree.c | 7 +++++++
4 files changed, 32 insertions(+), 1 deletion(-)
diff --git a/kernel/rcu/Kconfig.debug b/kernel/rcu/Kconfig.debug
index 3cf6132a4bb9f..3323e3378af5a 100644
--- a/kernel/rcu/Kconfig.debug
+++ b/kernel/rcu/Kconfig.debug
@@ -50,6 +50,7 @@ config RCU_TORTURE_TEST
select TASKS_RCU
select TASKS_RUDE_RCU
select TASKS_TRACE_RCU
+ select SCHEDSTATS
default n
help
This option provides a kernel module that runs torture tests
diff --git a/kernel/rcu/rcu.h b/kernel/rcu/rcu.h
index cf66a3ccd7573..7e867e81d9738 100644
--- a/kernel/rcu/rcu.h
+++ b/kernel/rcu/rcu.h
@@ -511,6 +511,7 @@ srcu_batches_completed(struct srcu_struct *sp) { return 0; }
static inline void rcu_force_quiescent_state(void) { }
static inline void show_rcu_gp_kthreads(void) { }
static inline int rcu_get_gp_kthreads_prio(void) { return 0; }
+static inline struct task_struct *rcu_get_main_gp_kthread(void) { return 0; }
static inline void rcu_fwd_progress_check(unsigned long j) { }
#else /* #ifdef CONFIG_TINY_RCU */
bool rcu_dynticks_zero_in_eqs(int cpu, int *vp);
@@ -519,6 +520,7 @@ unsigned long rcu_exp_batches_completed(void);
unsigned long srcu_batches_completed(struct srcu_struct *sp);
void show_rcu_gp_kthreads(void);
int rcu_get_gp_kthreads_prio(void);
+struct task_struct *rcu_get_main_gp_kthread(void);
void rcu_fwd_progress_check(unsigned long j);
void rcu_force_quiescent_state(void);
extern struct workqueue_struct *rcu_gp_wq;
diff --git a/kernel/rcu/rcutorture.c b/kernel/rcu/rcutorture.c
index d0d265304d147..959a1f84d6904 100644
--- a/kernel/rcu/rcutorture.c
+++ b/kernel/rcu/rcutorture.c
@@ -23,6 +23,7 @@
#include <linux/rcupdate_wait.h>
#include <linux/interrupt.h>
#include <linux/sched/signal.h>
+#include <linux/sched/stat.h>
#include <uapi/linux/sched/types.h>
#include <linux/atomic.h>
#include <linux/bitops.h>
@@ -460,9 +461,29 @@ static void rcu_sync_torture_init(void)
INIT_LIST_HEAD(&rcu_torture_removed);
}
+unsigned long rcu_gp_nr_wakeups;
+
+static void rcu_flavor_init(void)
+{
+ rcu_sync_torture_init();
+
+ /* Make sure schedstat is enabled for GP thread wakeup count. */
+ force_schedstat_enabled();
+ rcu_gp_nr_wakeups = rcu_get_main_gp_kthread()->se.statistics.nr_wakeups;
+}
+
+static void rcu_flavor_cleanup(void)
+{
+ unsigned long now_nr = rcu_get_main_gp_kthread()->se.statistics.nr_wakeups;
+
+ pr_alert("End-test: Cleanup: Total GP-kthread wakeups: %lu\n",
+ now_nr - rcu_gp_nr_wakeups);
+}
+
static struct rcu_torture_ops rcu_ops = {
.ttype = RCU_FLAVOR,
- .init = rcu_sync_torture_init,
+ .init = rcu_flavor_init,
+ .cleanup = rcu_flavor_cleanup,
.readlock = rcu_torture_read_lock,
.read_delay = rcu_read_delay,
.readunlock = rcu_torture_read_unlock,
diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index c3bae7a83d792..a3a175feb310a 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -175,6 +175,13 @@ int rcu_get_gp_kthreads_prio(void)
}
EXPORT_SYMBOL_GPL(rcu_get_gp_kthreads_prio);
+/* Retrieve RCU's main GP kthread task_struct */
+struct task_struct *rcu_get_main_gp_kthread(void)
+{
+ return rcu_state.gp_kthread;
+}
+EXPORT_SYMBOL_GPL(rcu_get_main_gp_kthread);
+
/*
* Number of grace periods between delays, normalized by the duration of
* the delay. The longer the delay, the more the grace periods between
--
2.27.0.111.gc72c7da667-goog
On Thu, Jun 18, 2020 at 04:29:54PM -0400, Joel Fernandes (Google) wrote:
> This is useful to check for any improvements or degradation related to
> number of GP kthread wakeups during testing.
>
> Signed-off-by: Joel Fernandes (Google) <[email protected]>
This was a good way to collect the data for your testing, but
we can expect rcutorture to only do so much. ;-)
Thanx, Paul
> ---
> kernel/rcu/Kconfig.debug | 1 +
> kernel/rcu/rcu.h | 2 ++
> kernel/rcu/rcutorture.c | 23 ++++++++++++++++++++++-
> kernel/rcu/tree.c | 7 +++++++
> 4 files changed, 32 insertions(+), 1 deletion(-)
>
> diff --git a/kernel/rcu/Kconfig.debug b/kernel/rcu/Kconfig.debug
> index 3cf6132a4bb9f..3323e3378af5a 100644
> --- a/kernel/rcu/Kconfig.debug
> +++ b/kernel/rcu/Kconfig.debug
> @@ -50,6 +50,7 @@ config RCU_TORTURE_TEST
> select TASKS_RCU
> select TASKS_RUDE_RCU
> select TASKS_TRACE_RCU
> + select SCHEDSTATS
> default n
> help
> This option provides a kernel module that runs torture tests
> diff --git a/kernel/rcu/rcu.h b/kernel/rcu/rcu.h
> index cf66a3ccd7573..7e867e81d9738 100644
> --- a/kernel/rcu/rcu.h
> +++ b/kernel/rcu/rcu.h
> @@ -511,6 +511,7 @@ srcu_batches_completed(struct srcu_struct *sp) { return 0; }
> static inline void rcu_force_quiescent_state(void) { }
> static inline void show_rcu_gp_kthreads(void) { }
> static inline int rcu_get_gp_kthreads_prio(void) { return 0; }
> +static inline struct task_struct *rcu_get_main_gp_kthread(void) { return 0; }
> static inline void rcu_fwd_progress_check(unsigned long j) { }
> #else /* #ifdef CONFIG_TINY_RCU */
> bool rcu_dynticks_zero_in_eqs(int cpu, int *vp);
> @@ -519,6 +520,7 @@ unsigned long rcu_exp_batches_completed(void);
> unsigned long srcu_batches_completed(struct srcu_struct *sp);
> void show_rcu_gp_kthreads(void);
> int rcu_get_gp_kthreads_prio(void);
> +struct task_struct *rcu_get_main_gp_kthread(void);
> void rcu_fwd_progress_check(unsigned long j);
> void rcu_force_quiescent_state(void);
> extern struct workqueue_struct *rcu_gp_wq;
> diff --git a/kernel/rcu/rcutorture.c b/kernel/rcu/rcutorture.c
> index d0d265304d147..959a1f84d6904 100644
> --- a/kernel/rcu/rcutorture.c
> +++ b/kernel/rcu/rcutorture.c
> @@ -23,6 +23,7 @@
> #include <linux/rcupdate_wait.h>
> #include <linux/interrupt.h>
> #include <linux/sched/signal.h>
> +#include <linux/sched/stat.h>
> #include <uapi/linux/sched/types.h>
> #include <linux/atomic.h>
> #include <linux/bitops.h>
> @@ -460,9 +461,29 @@ static void rcu_sync_torture_init(void)
> INIT_LIST_HEAD(&rcu_torture_removed);
> }
>
> +unsigned long rcu_gp_nr_wakeups;
> +
> +static void rcu_flavor_init(void)
> +{
> + rcu_sync_torture_init();
> +
> + /* Make sure schedstat is enabled for GP thread wakeup count. */
> + force_schedstat_enabled();
> + rcu_gp_nr_wakeups = rcu_get_main_gp_kthread()->se.statistics.nr_wakeups;
> +}
> +
> +static void rcu_flavor_cleanup(void)
> +{
> + unsigned long now_nr = rcu_get_main_gp_kthread()->se.statistics.nr_wakeups;
> +
> + pr_alert("End-test: Cleanup: Total GP-kthread wakeups: %lu\n",
> + now_nr - rcu_gp_nr_wakeups);
> +}
> +
> static struct rcu_torture_ops rcu_ops = {
> .ttype = RCU_FLAVOR,
> - .init = rcu_sync_torture_init,
> + .init = rcu_flavor_init,
> + .cleanup = rcu_flavor_cleanup,
> .readlock = rcu_torture_read_lock,
> .read_delay = rcu_read_delay,
> .readunlock = rcu_torture_read_unlock,
> diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
> index c3bae7a83d792..a3a175feb310a 100644
> --- a/kernel/rcu/tree.c
> +++ b/kernel/rcu/tree.c
> @@ -175,6 +175,13 @@ int rcu_get_gp_kthreads_prio(void)
> }
> EXPORT_SYMBOL_GPL(rcu_get_gp_kthreads_prio);
>
> +/* Retrieve RCU's main GP kthread task_struct */
> +struct task_struct *rcu_get_main_gp_kthread(void)
> +{
> + return rcu_state.gp_kthread;
> +}
> +EXPORT_SYMBOL_GPL(rcu_get_main_gp_kthread);
> +
> /*
> * Number of grace periods between delays, normalized by the duration of
> * the delay. The longer the delay, the more the grace periods between
> --
> 2.27.0.111.gc72c7da667-goog
>
On Thu, Jun 18, 2020 at 03:40:58PM -0700, Paul E. McKenney wrote:
> On Thu, Jun 18, 2020 at 04:29:54PM -0400, Joel Fernandes (Google) wrote:
> > This is useful to check for any improvements or degradation related to
> > number of GP kthread wakeups during testing.
> >
> > Signed-off-by: Joel Fernandes (Google) <[email protected]>
>
> This was a good way to collect the data for your testing, but
> we can expect rcutorture to only do so much. ;-)
np, I will push this one into a git tag for the next time I need it ;)
thanks,
- Joel
> Thanx, Paul
>
> > ---
> > kernel/rcu/Kconfig.debug | 1 +
> > kernel/rcu/rcu.h | 2 ++
> > kernel/rcu/rcutorture.c | 23 ++++++++++++++++++++++-
> > kernel/rcu/tree.c | 7 +++++++
> > 4 files changed, 32 insertions(+), 1 deletion(-)
> >
> > diff --git a/kernel/rcu/Kconfig.debug b/kernel/rcu/Kconfig.debug
> > index 3cf6132a4bb9f..3323e3378af5a 100644
> > --- a/kernel/rcu/Kconfig.debug
> > +++ b/kernel/rcu/Kconfig.debug
> > @@ -50,6 +50,7 @@ config RCU_TORTURE_TEST
> > select TASKS_RCU
> > select TASKS_RUDE_RCU
> > select TASKS_TRACE_RCU
> > + select SCHEDSTATS
> > default n
> > help
> > This option provides a kernel module that runs torture tests
> > diff --git a/kernel/rcu/rcu.h b/kernel/rcu/rcu.h
> > index cf66a3ccd7573..7e867e81d9738 100644
> > --- a/kernel/rcu/rcu.h
> > +++ b/kernel/rcu/rcu.h
> > @@ -511,6 +511,7 @@ srcu_batches_completed(struct srcu_struct *sp) { return 0; }
> > static inline void rcu_force_quiescent_state(void) { }
> > static inline void show_rcu_gp_kthreads(void) { }
> > static inline int rcu_get_gp_kthreads_prio(void) { return 0; }
> > +static inline struct task_struct *rcu_get_main_gp_kthread(void) { return 0; }
> > static inline void rcu_fwd_progress_check(unsigned long j) { }
> > #else /* #ifdef CONFIG_TINY_RCU */
> > bool rcu_dynticks_zero_in_eqs(int cpu, int *vp);
> > @@ -519,6 +520,7 @@ unsigned long rcu_exp_batches_completed(void);
> > unsigned long srcu_batches_completed(struct srcu_struct *sp);
> > void show_rcu_gp_kthreads(void);
> > int rcu_get_gp_kthreads_prio(void);
> > +struct task_struct *rcu_get_main_gp_kthread(void);
> > void rcu_fwd_progress_check(unsigned long j);
> > void rcu_force_quiescent_state(void);
> > extern struct workqueue_struct *rcu_gp_wq;
> > diff --git a/kernel/rcu/rcutorture.c b/kernel/rcu/rcutorture.c
> > index d0d265304d147..959a1f84d6904 100644
> > --- a/kernel/rcu/rcutorture.c
> > +++ b/kernel/rcu/rcutorture.c
> > @@ -23,6 +23,7 @@
> > #include <linux/rcupdate_wait.h>
> > #include <linux/interrupt.h>
> > #include <linux/sched/signal.h>
> > +#include <linux/sched/stat.h>
> > #include <uapi/linux/sched/types.h>
> > #include <linux/atomic.h>
> > #include <linux/bitops.h>
> > @@ -460,9 +461,29 @@ static void rcu_sync_torture_init(void)
> > INIT_LIST_HEAD(&rcu_torture_removed);
> > }
> >
> > +unsigned long rcu_gp_nr_wakeups;
> > +
> > +static void rcu_flavor_init(void)
> > +{
> > + rcu_sync_torture_init();
> > +
> > + /* Make sure schedstat is enabled for GP thread wakeup count. */
> > + force_schedstat_enabled();
> > + rcu_gp_nr_wakeups = rcu_get_main_gp_kthread()->se.statistics.nr_wakeups;
> > +}
> > +
> > +static void rcu_flavor_cleanup(void)
> > +{
> > + unsigned long now_nr = rcu_get_main_gp_kthread()->se.statistics.nr_wakeups;
> > +
> > + pr_alert("End-test: Cleanup: Total GP-kthread wakeups: %lu\n",
> > + now_nr - rcu_gp_nr_wakeups);
> > +}
> > +
> > static struct rcu_torture_ops rcu_ops = {
> > .ttype = RCU_FLAVOR,
> > - .init = rcu_sync_torture_init,
> > + .init = rcu_flavor_init,
> > + .cleanup = rcu_flavor_cleanup,
> > .readlock = rcu_torture_read_lock,
> > .read_delay = rcu_read_delay,
> > .readunlock = rcu_torture_read_unlock,
> > diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
> > index c3bae7a83d792..a3a175feb310a 100644
> > --- a/kernel/rcu/tree.c
> > +++ b/kernel/rcu/tree.c
> > @@ -175,6 +175,13 @@ int rcu_get_gp_kthreads_prio(void)
> > }
> > EXPORT_SYMBOL_GPL(rcu_get_gp_kthreads_prio);
> >
> > +/* Retrieve RCU's main GP kthread task_struct */
> > +struct task_struct *rcu_get_main_gp_kthread(void)
> > +{
> > + return rcu_state.gp_kthread;
> > +}
> > +EXPORT_SYMBOL_GPL(rcu_get_main_gp_kthread);
> > +
> > /*
> > * Number of grace periods between delays, normalized by the duration of
> > * the delay. The longer the delay, the more the grace periods between
> > --
> > 2.27.0.111.gc72c7da667-goog
> >
On Thu, Jun 18, 2020 at 08:01:56PM -0400, Joel Fernandes wrote:
> On Thu, Jun 18, 2020 at 03:40:58PM -0700, Paul E. McKenney wrote:
> > On Thu, Jun 18, 2020 at 04:29:54PM -0400, Joel Fernandes (Google) wrote:
> > > This is useful to check for any improvements or degradation related to
> > > number of GP kthread wakeups during testing.
> > >
> > > Signed-off-by: Joel Fernandes (Google) <[email protected]>
> >
> > This was a good way to collect the data for your testing, but
> > we can expect rcutorture to only do so much. ;-)
>
> np, I will push this one into a git tag for the next time I need it ;)
Sounds like a plan!
Thanx, Paul
> thanks,
>
> - Joel
>
>
> > Thanx, Paul
> >
> > > ---
> > > kernel/rcu/Kconfig.debug | 1 +
> > > kernel/rcu/rcu.h | 2 ++
> > > kernel/rcu/rcutorture.c | 23 ++++++++++++++++++++++-
> > > kernel/rcu/tree.c | 7 +++++++
> > > 4 files changed, 32 insertions(+), 1 deletion(-)
> > >
> > > diff --git a/kernel/rcu/Kconfig.debug b/kernel/rcu/Kconfig.debug
> > > index 3cf6132a4bb9f..3323e3378af5a 100644
> > > --- a/kernel/rcu/Kconfig.debug
> > > +++ b/kernel/rcu/Kconfig.debug
> > > @@ -50,6 +50,7 @@ config RCU_TORTURE_TEST
> > > select TASKS_RCU
> > > select TASKS_RUDE_RCU
> > > select TASKS_TRACE_RCU
> > > + select SCHEDSTATS
> > > default n
> > > help
> > > This option provides a kernel module that runs torture tests
> > > diff --git a/kernel/rcu/rcu.h b/kernel/rcu/rcu.h
> > > index cf66a3ccd7573..7e867e81d9738 100644
> > > --- a/kernel/rcu/rcu.h
> > > +++ b/kernel/rcu/rcu.h
> > > @@ -511,6 +511,7 @@ srcu_batches_completed(struct srcu_struct *sp) { return 0; }
> > > static inline void rcu_force_quiescent_state(void) { }
> > > static inline void show_rcu_gp_kthreads(void) { }
> > > static inline int rcu_get_gp_kthreads_prio(void) { return 0; }
> > > +static inline struct task_struct *rcu_get_main_gp_kthread(void) { return 0; }
> > > static inline void rcu_fwd_progress_check(unsigned long j) { }
> > > #else /* #ifdef CONFIG_TINY_RCU */
> > > bool rcu_dynticks_zero_in_eqs(int cpu, int *vp);
> > > @@ -519,6 +520,7 @@ unsigned long rcu_exp_batches_completed(void);
> > > unsigned long srcu_batches_completed(struct srcu_struct *sp);
> > > void show_rcu_gp_kthreads(void);
> > > int rcu_get_gp_kthreads_prio(void);
> > > +struct task_struct *rcu_get_main_gp_kthread(void);
> > > void rcu_fwd_progress_check(unsigned long j);
> > > void rcu_force_quiescent_state(void);
> > > extern struct workqueue_struct *rcu_gp_wq;
> > > diff --git a/kernel/rcu/rcutorture.c b/kernel/rcu/rcutorture.c
> > > index d0d265304d147..959a1f84d6904 100644
> > > --- a/kernel/rcu/rcutorture.c
> > > +++ b/kernel/rcu/rcutorture.c
> > > @@ -23,6 +23,7 @@
> > > #include <linux/rcupdate_wait.h>
> > > #include <linux/interrupt.h>
> > > #include <linux/sched/signal.h>
> > > +#include <linux/sched/stat.h>
> > > #include <uapi/linux/sched/types.h>
> > > #include <linux/atomic.h>
> > > #include <linux/bitops.h>
> > > @@ -460,9 +461,29 @@ static void rcu_sync_torture_init(void)
> > > INIT_LIST_HEAD(&rcu_torture_removed);
> > > }
> > >
> > > +unsigned long rcu_gp_nr_wakeups;
> > > +
> > > +static void rcu_flavor_init(void)
> > > +{
> > > + rcu_sync_torture_init();
> > > +
> > > + /* Make sure schedstat is enabled for GP thread wakeup count. */
> > > + force_schedstat_enabled();
> > > + rcu_gp_nr_wakeups = rcu_get_main_gp_kthread()->se.statistics.nr_wakeups;
> > > +}
> > > +
> > > +static void rcu_flavor_cleanup(void)
> > > +{
> > > + unsigned long now_nr = rcu_get_main_gp_kthread()->se.statistics.nr_wakeups;
> > > +
> > > + pr_alert("End-test: Cleanup: Total GP-kthread wakeups: %lu\n",
> > > + now_nr - rcu_gp_nr_wakeups);
> > > +}
> > > +
> > > static struct rcu_torture_ops rcu_ops = {
> > > .ttype = RCU_FLAVOR,
> > > - .init = rcu_sync_torture_init,
> > > + .init = rcu_flavor_init,
> > > + .cleanup = rcu_flavor_cleanup,
> > > .readlock = rcu_torture_read_lock,
> > > .read_delay = rcu_read_delay,
> > > .readunlock = rcu_torture_read_unlock,
> > > diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
> > > index c3bae7a83d792..a3a175feb310a 100644
> > > --- a/kernel/rcu/tree.c
> > > +++ b/kernel/rcu/tree.c
> > > @@ -175,6 +175,13 @@ int rcu_get_gp_kthreads_prio(void)
> > > }
> > > EXPORT_SYMBOL_GPL(rcu_get_gp_kthreads_prio);
> > >
> > > +/* Retrieve RCU's main GP kthread task_struct */
> > > +struct task_struct *rcu_get_main_gp_kthread(void)
> > > +{
> > > + return rcu_state.gp_kthread;
> > > +}
> > > +EXPORT_SYMBOL_GPL(rcu_get_main_gp_kthread);
> > > +
> > > /*
> > > * Number of grace periods between delays, normalized by the duration of
> > > * the delay. The longer the delay, the more the grace periods between
> > > --
> > > 2.27.0.111.gc72c7da667-goog
> > >
On Thu, Jun 18, 2020 at 05:12:44PM -0700, Paul E. McKenney wrote:
> On Thu, Jun 18, 2020 at 08:01:56PM -0400, Joel Fernandes wrote:
> > On Thu, Jun 18, 2020 at 03:40:58PM -0700, Paul E. McKenney wrote:
> > > On Thu, Jun 18, 2020 at 04:29:54PM -0400, Joel Fernandes (Google) wrote:
> > > > This is useful to check for any improvements or degradation related to
> > > > number of GP kthread wakeups during testing.
> > > >
> > > > Signed-off-by: Joel Fernandes (Google) <[email protected]>
> > >
> > > This was a good way to collect the data for your testing, but
> > > we can expect rcutorture to only do so much. ;-)
> >
> > np, I will push this one into a git tag for the next time I need it ;)
>
> Sounds like a plan!
In case it is at all an option, I could put this as a statistic under
rcu_torture_stats_print(), that way it all is on the same line. But I take it
you are not too thrilled to have it for now.
thanks,
- Joel
> Thanx, Paul
>
> > thanks,
> >
> > - Joel
> >
> >
> > > Thanx, Paul
> > >
> > > > ---
> > > > kernel/rcu/Kconfig.debug | 1 +
> > > > kernel/rcu/rcu.h | 2 ++
> > > > kernel/rcu/rcutorture.c | 23 ++++++++++++++++++++++-
> > > > kernel/rcu/tree.c | 7 +++++++
> > > > 4 files changed, 32 insertions(+), 1 deletion(-)
> > > >
> > > > diff --git a/kernel/rcu/Kconfig.debug b/kernel/rcu/Kconfig.debug
> > > > index 3cf6132a4bb9f..3323e3378af5a 100644
> > > > --- a/kernel/rcu/Kconfig.debug
> > > > +++ b/kernel/rcu/Kconfig.debug
> > > > @@ -50,6 +50,7 @@ config RCU_TORTURE_TEST
> > > > select TASKS_RCU
> > > > select TASKS_RUDE_RCU
> > > > select TASKS_TRACE_RCU
> > > > + select SCHEDSTATS
> > > > default n
> > > > help
> > > > This option provides a kernel module that runs torture tests
> > > > diff --git a/kernel/rcu/rcu.h b/kernel/rcu/rcu.h
> > > > index cf66a3ccd7573..7e867e81d9738 100644
> > > > --- a/kernel/rcu/rcu.h
> > > > +++ b/kernel/rcu/rcu.h
> > > > @@ -511,6 +511,7 @@ srcu_batches_completed(struct srcu_struct *sp) { return 0; }
> > > > static inline void rcu_force_quiescent_state(void) { }
> > > > static inline void show_rcu_gp_kthreads(void) { }
> > > > static inline int rcu_get_gp_kthreads_prio(void) { return 0; }
> > > > +static inline struct task_struct *rcu_get_main_gp_kthread(void) { return 0; }
> > > > static inline void rcu_fwd_progress_check(unsigned long j) { }
> > > > #else /* #ifdef CONFIG_TINY_RCU */
> > > > bool rcu_dynticks_zero_in_eqs(int cpu, int *vp);
> > > > @@ -519,6 +520,7 @@ unsigned long rcu_exp_batches_completed(void);
> > > > unsigned long srcu_batches_completed(struct srcu_struct *sp);
> > > > void show_rcu_gp_kthreads(void);
> > > > int rcu_get_gp_kthreads_prio(void);
> > > > +struct task_struct *rcu_get_main_gp_kthread(void);
> > > > void rcu_fwd_progress_check(unsigned long j);
> > > > void rcu_force_quiescent_state(void);
> > > > extern struct workqueue_struct *rcu_gp_wq;
> > > > diff --git a/kernel/rcu/rcutorture.c b/kernel/rcu/rcutorture.c
> > > > index d0d265304d147..959a1f84d6904 100644
> > > > --- a/kernel/rcu/rcutorture.c
> > > > +++ b/kernel/rcu/rcutorture.c
> > > > @@ -23,6 +23,7 @@
> > > > #include <linux/rcupdate_wait.h>
> > > > #include <linux/interrupt.h>
> > > > #include <linux/sched/signal.h>
> > > > +#include <linux/sched/stat.h>
> > > > #include <uapi/linux/sched/types.h>
> > > > #include <linux/atomic.h>
> > > > #include <linux/bitops.h>
> > > > @@ -460,9 +461,29 @@ static void rcu_sync_torture_init(void)
> > > > INIT_LIST_HEAD(&rcu_torture_removed);
> > > > }
> > > >
> > > > +unsigned long rcu_gp_nr_wakeups;
> > > > +
> > > > +static void rcu_flavor_init(void)
> > > > +{
> > > > + rcu_sync_torture_init();
> > > > +
> > > > + /* Make sure schedstat is enabled for GP thread wakeup count. */
> > > > + force_schedstat_enabled();
> > > > + rcu_gp_nr_wakeups = rcu_get_main_gp_kthread()->se.statistics.nr_wakeups;
> > > > +}
> > > > +
> > > > +static void rcu_flavor_cleanup(void)
> > > > +{
> > > > + unsigned long now_nr = rcu_get_main_gp_kthread()->se.statistics.nr_wakeups;
> > > > +
> > > > + pr_alert("End-test: Cleanup: Total GP-kthread wakeups: %lu\n",
> > > > + now_nr - rcu_gp_nr_wakeups);
> > > > +}
> > > > +
> > > > static struct rcu_torture_ops rcu_ops = {
> > > > .ttype = RCU_FLAVOR,
> > > > - .init = rcu_sync_torture_init,
> > > > + .init = rcu_flavor_init,
> > > > + .cleanup = rcu_flavor_cleanup,
> > > > .readlock = rcu_torture_read_lock,
> > > > .read_delay = rcu_read_delay,
> > > > .readunlock = rcu_torture_read_unlock,
> > > > diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
> > > > index c3bae7a83d792..a3a175feb310a 100644
> > > > --- a/kernel/rcu/tree.c
> > > > +++ b/kernel/rcu/tree.c
> > > > @@ -175,6 +175,13 @@ int rcu_get_gp_kthreads_prio(void)
> > > > }
> > > > EXPORT_SYMBOL_GPL(rcu_get_gp_kthreads_prio);
> > > >
> > > > +/* Retrieve RCU's main GP kthread task_struct */
> > > > +struct task_struct *rcu_get_main_gp_kthread(void)
> > > > +{
> > > > + return rcu_state.gp_kthread;
> > > > +}
> > > > +EXPORT_SYMBOL_GPL(rcu_get_main_gp_kthread);
> > > > +
> > > > /*
> > > > * Number of grace periods between delays, normalized by the duration of
> > > > * the delay. The longer the delay, the more the grace periods between
> > > > --
> > > > 2.27.0.111.gc72c7da667-goog
> > > >
On Thu, Jun 18, 2020 at 09:00:12PM -0400, Joel Fernandes wrote:
> On Thu, Jun 18, 2020 at 05:12:44PM -0700, Paul E. McKenney wrote:
> > On Thu, Jun 18, 2020 at 08:01:56PM -0400, Joel Fernandes wrote:
> > > On Thu, Jun 18, 2020 at 03:40:58PM -0700, Paul E. McKenney wrote:
> > > > On Thu, Jun 18, 2020 at 04:29:54PM -0400, Joel Fernandes (Google) wrote:
> > > > > This is useful to check for any improvements or degradation related to
> > > > > number of GP kthread wakeups during testing.
> > > > >
> > > > > Signed-off-by: Joel Fernandes (Google) <[email protected]>
> > > >
> > > > This was a good way to collect the data for your testing, but
> > > > we can expect rcutorture to only do so much. ;-)
> > >
> > > np, I will push this one into a git tag for the next time I need it ;)
> >
> > Sounds like a plan!
>
> In case it is at all an option, I could put this as a statistic under
> rcu_torture_stats_print(), that way it all is on the same line. But I take it
> you are not too thrilled to have it for now.
The thing is that rcutorture is a stress test, not a performance or
energy-efficiency test. So rcutorture will continue to wake things
up just to brutalize RCU, which makes such a statistic less helpful.
It might be something for rcuperf/rcuscale, although it is not clear that
a pure performance/scalability test would give a useful read on wakeups.
I would expect better results from a more random real-world workload.
But I bet that people already have this sort of thing set up. For
example, doesn't kbuild test robot track this sort of thing?
Thanx, Paul
> thanks,
>
> - Joel
>
>
>
> > Thanx, Paul
> >
> > > thanks,
> > >
> > > - Joel
> > >
> > >
> > > > Thanx, Paul
> > > >
> > > > > ---
> > > > > kernel/rcu/Kconfig.debug | 1 +
> > > > > kernel/rcu/rcu.h | 2 ++
> > > > > kernel/rcu/rcutorture.c | 23 ++++++++++++++++++++++-
> > > > > kernel/rcu/tree.c | 7 +++++++
> > > > > 4 files changed, 32 insertions(+), 1 deletion(-)
> > > > >
> > > > > diff --git a/kernel/rcu/Kconfig.debug b/kernel/rcu/Kconfig.debug
> > > > > index 3cf6132a4bb9f..3323e3378af5a 100644
> > > > > --- a/kernel/rcu/Kconfig.debug
> > > > > +++ b/kernel/rcu/Kconfig.debug
> > > > > @@ -50,6 +50,7 @@ config RCU_TORTURE_TEST
> > > > > select TASKS_RCU
> > > > > select TASKS_RUDE_RCU
> > > > > select TASKS_TRACE_RCU
> > > > > + select SCHEDSTATS
> > > > > default n
> > > > > help
> > > > > This option provides a kernel module that runs torture tests
> > > > > diff --git a/kernel/rcu/rcu.h b/kernel/rcu/rcu.h
> > > > > index cf66a3ccd7573..7e867e81d9738 100644
> > > > > --- a/kernel/rcu/rcu.h
> > > > > +++ b/kernel/rcu/rcu.h
> > > > > @@ -511,6 +511,7 @@ srcu_batches_completed(struct srcu_struct *sp) { return 0; }
> > > > > static inline void rcu_force_quiescent_state(void) { }
> > > > > static inline void show_rcu_gp_kthreads(void) { }
> > > > > static inline int rcu_get_gp_kthreads_prio(void) { return 0; }
> > > > > +static inline struct task_struct *rcu_get_main_gp_kthread(void) { return 0; }
> > > > > static inline void rcu_fwd_progress_check(unsigned long j) { }
> > > > > #else /* #ifdef CONFIG_TINY_RCU */
> > > > > bool rcu_dynticks_zero_in_eqs(int cpu, int *vp);
> > > > > @@ -519,6 +520,7 @@ unsigned long rcu_exp_batches_completed(void);
> > > > > unsigned long srcu_batches_completed(struct srcu_struct *sp);
> > > > > void show_rcu_gp_kthreads(void);
> > > > > int rcu_get_gp_kthreads_prio(void);
> > > > > +struct task_struct *rcu_get_main_gp_kthread(void);
> > > > > void rcu_fwd_progress_check(unsigned long j);
> > > > > void rcu_force_quiescent_state(void);
> > > > > extern struct workqueue_struct *rcu_gp_wq;
> > > > > diff --git a/kernel/rcu/rcutorture.c b/kernel/rcu/rcutorture.c
> > > > > index d0d265304d147..959a1f84d6904 100644
> > > > > --- a/kernel/rcu/rcutorture.c
> > > > > +++ b/kernel/rcu/rcutorture.c
> > > > > @@ -23,6 +23,7 @@
> > > > > #include <linux/rcupdate_wait.h>
> > > > > #include <linux/interrupt.h>
> > > > > #include <linux/sched/signal.h>
> > > > > +#include <linux/sched/stat.h>
> > > > > #include <uapi/linux/sched/types.h>
> > > > > #include <linux/atomic.h>
> > > > > #include <linux/bitops.h>
> > > > > @@ -460,9 +461,29 @@ static void rcu_sync_torture_init(void)
> > > > > INIT_LIST_HEAD(&rcu_torture_removed);
> > > > > }
> > > > >
> > > > > +unsigned long rcu_gp_nr_wakeups;
> > > > > +
> > > > > +static void rcu_flavor_init(void)
> > > > > +{
> > > > > + rcu_sync_torture_init();
> > > > > +
> > > > > + /* Make sure schedstat is enabled for GP thread wakeup count. */
> > > > > + force_schedstat_enabled();
> > > > > + rcu_gp_nr_wakeups = rcu_get_main_gp_kthread()->se.statistics.nr_wakeups;
> > > > > +}
> > > > > +
> > > > > +static void rcu_flavor_cleanup(void)
> > > > > +{
> > > > > + unsigned long now_nr = rcu_get_main_gp_kthread()->se.statistics.nr_wakeups;
> > > > > +
> > > > > + pr_alert("End-test: Cleanup: Total GP-kthread wakeups: %lu\n",
> > > > > + now_nr - rcu_gp_nr_wakeups);
> > > > > +}
> > > > > +
> > > > > static struct rcu_torture_ops rcu_ops = {
> > > > > .ttype = RCU_FLAVOR,
> > > > > - .init = rcu_sync_torture_init,
> > > > > + .init = rcu_flavor_init,
> > > > > + .cleanup = rcu_flavor_cleanup,
> > > > > .readlock = rcu_torture_read_lock,
> > > > > .read_delay = rcu_read_delay,
> > > > > .readunlock = rcu_torture_read_unlock,
> > > > > diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
> > > > > index c3bae7a83d792..a3a175feb310a 100644
> > > > > --- a/kernel/rcu/tree.c
> > > > > +++ b/kernel/rcu/tree.c
> > > > > @@ -175,6 +175,13 @@ int rcu_get_gp_kthreads_prio(void)
> > > > > }
> > > > > EXPORT_SYMBOL_GPL(rcu_get_gp_kthreads_prio);
> > > > >
> > > > > +/* Retrieve RCU's main GP kthread task_struct */
> > > > > +struct task_struct *rcu_get_main_gp_kthread(void)
> > > > > +{
> > > > > + return rcu_state.gp_kthread;
> > > > > +}
> > > > > +EXPORT_SYMBOL_GPL(rcu_get_main_gp_kthread);
> > > > > +
> > > > > /*
> > > > > * Number of grace periods between delays, normalized by the duration of
> > > > > * the delay. The longer the delay, the more the grace periods between
> > > > > --
> > > > > 2.27.0.111.gc72c7da667-goog
> > > > >