| Message ID | 20240104162510.72773-3-urezki@gmail.com (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | c8e6fef0fc0968db0447d21054dcc59ce578357e |
| Headers | show |
| Series | Reduce synchronize_rcu() latency(v4) | expand |
Le Thu, Jan 04, 2024 at 05:25:08PM +0100, Uladzislau Rezki (Sony) a écrit : > Add an rcu_sr_normal() trace event. It takes three arguments > first one is the name of RCU flavour, second one is a user id > which triggeres synchronize_rcu_normal() and last one is an > event. > > There are two traces in the synchronize_rcu_normal(). On entry, > when a new request is registered and on exit point when request > is completed. > > Please note, CONFIG_RCU_TRACE=y is required to activate traces. > > Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com> > --- > include/trace/events/rcu.h | 27 +++++++++++++++++++++++++++ > kernel/rcu/tree.c | 7 ++++++- > 2 files changed, 33 insertions(+), 1 deletion(-) > > diff --git a/include/trace/events/rcu.h b/include/trace/events/rcu.h > index 2ef9c719772a..31b3e0d3e65f 100644 > --- a/include/trace/events/rcu.h > +++ b/include/trace/events/rcu.h > @@ -707,6 +707,33 @@ TRACE_EVENT_RCU(rcu_invoke_kfree_bulk_callback, > __entry->rcuname, __entry->p, __entry->nr_records) > ); > > +/* > + * Tracepoint for a normal synchronize_rcu() states. The first argument > + * is the RCU flavor, the second argument is a pointer to rcu_head the > + * last one is an event. > + */ > +TRACE_EVENT_RCU(rcu_sr_normal, Can we call this "synchronize_rcu" instead? So people really know what it's about. Then should the need arise, we can still add "synchronize_rcu_expedited" trace events later. Thanks. > + > + TP_PROTO(const char *rcuname, struct rcu_head *rhp, const char *srevent), > + > + TP_ARGS(rcuname, rhp, srevent), > + > + TP_STRUCT__entry( > + __field(const char *, rcuname) > + __field(void *, rhp) > + __field(const char *, srevent) > + ), > + > + TP_fast_assign( > + __entry->rcuname = rcuname; > + __entry->rhp = rhp; > + __entry->srevent = srevent; > + ), > + > + TP_printk("%s rhp=0x%p event=%s", > + __entry->rcuname, __entry->rhp, __entry->srevent) > +); > + > /* > * Tracepoint for exiting rcu_do_batch after RCU callbacks have been > * invoked. The first argument is the name of the RCU flavor, > diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c > index b756c40e4960..7d2ed89efcb3 100644 > --- a/kernel/rcu/tree.c > +++ b/kernel/rcu/tree.c > @@ -3672,9 +3672,11 @@ static void synchronize_rcu_normal(void) > { > struct rcu_synchronize rs; > > + trace_rcu_sr_normal(rcu_state.name, &rs.head, TPS("request")); > + > if (!READ_ONCE(rcu_normal_wake_from_gp)) { > wait_rcu_gp(call_rcu_hurry); > - return; > + goto trace_complete_out; > } > > init_rcu_head_on_stack(&rs.head); > @@ -3695,6 +3697,9 @@ static void synchronize_rcu_normal(void) > /* Now we can wait. */ > wait_for_completion(&rs.completion); > destroy_rcu_head_on_stack(&rs.head); > + > +trace_complete_out: > + trace_rcu_sr_normal(rcu_state.name, &rs.head, TPS("complete")); > } > > /** > -- > 2.39.2 >
On Sat, Jan 13, 2024 at 12:20:14AM +0100, Frederic Weisbecker wrote: > Le Thu, Jan 04, 2024 at 05:25:08PM +0100, Uladzislau Rezki (Sony) a écrit : > > Add an rcu_sr_normal() trace event. It takes three arguments > > first one is the name of RCU flavour, second one is a user id > > which triggeres synchronize_rcu_normal() and last one is an > > event. > > > > There are two traces in the synchronize_rcu_normal(). On entry, > > when a new request is registered and on exit point when request > > is completed. > > > > Please note, CONFIG_RCU_TRACE=y is required to activate traces. > > > > Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com> > > --- > > include/trace/events/rcu.h | 27 +++++++++++++++++++++++++++ > > kernel/rcu/tree.c | 7 ++++++- > > 2 files changed, 33 insertions(+), 1 deletion(-) > > > > diff --git a/include/trace/events/rcu.h b/include/trace/events/rcu.h > > index 2ef9c719772a..31b3e0d3e65f 100644 > > --- a/include/trace/events/rcu.h > > +++ b/include/trace/events/rcu.h > > @@ -707,6 +707,33 @@ TRACE_EVENT_RCU(rcu_invoke_kfree_bulk_callback, > > __entry->rcuname, __entry->p, __entry->nr_records) > > ); > > > > +/* > > + * Tracepoint for a normal synchronize_rcu() states. The first argument > > + * is the RCU flavor, the second argument is a pointer to rcu_head the > > + * last one is an event. > > + */ > > +TRACE_EVENT_RCU(rcu_sr_normal, > > Can we call this "synchronize_rcu" instead? So people really know what it's > about. > I will update it accordingly! -- Uladzislau Rezki
diff --git a/include/trace/events/rcu.h b/include/trace/events/rcu.h index 2ef9c719772a..31b3e0d3e65f 100644 --- a/include/trace/events/rcu.h +++ b/include/trace/events/rcu.h @@ -707,6 +707,33 @@ TRACE_EVENT_RCU(rcu_invoke_kfree_bulk_callback, __entry->rcuname, __entry->p, __entry->nr_records) ); +/* + * Tracepoint for a normal synchronize_rcu() states. The first argument + * is the RCU flavor, the second argument is a pointer to rcu_head the + * last one is an event. + */ +TRACE_EVENT_RCU(rcu_sr_normal, + + TP_PROTO(const char *rcuname, struct rcu_head *rhp, const char *srevent), + + TP_ARGS(rcuname, rhp, srevent), + + TP_STRUCT__entry( + __field(const char *, rcuname) + __field(void *, rhp) + __field(const char *, srevent) + ), + + TP_fast_assign( + __entry->rcuname = rcuname; + __entry->rhp = rhp; + __entry->srevent = srevent; + ), + + TP_printk("%s rhp=0x%p event=%s", + __entry->rcuname, __entry->rhp, __entry->srevent) +); + /* * Tracepoint for exiting rcu_do_batch after RCU callbacks have been * invoked. The first argument is the name of the RCU flavor, diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index b756c40e4960..7d2ed89efcb3 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -3672,9 +3672,11 @@ static void synchronize_rcu_normal(void) { struct rcu_synchronize rs; + trace_rcu_sr_normal(rcu_state.name, &rs.head, TPS("request")); + if (!READ_ONCE(rcu_normal_wake_from_gp)) { wait_rcu_gp(call_rcu_hurry); - return; + goto trace_complete_out; } init_rcu_head_on_stack(&rs.head); @@ -3695,6 +3697,9 @@ static void synchronize_rcu_normal(void) /* Now we can wait. */ wait_for_completion(&rs.completion); destroy_rcu_head_on_stack(&rs.head); + +trace_complete_out: + trace_rcu_sr_normal(rcu_state.name, &rs.head, TPS("complete")); } /**
Add an rcu_sr_normal() trace event. It takes three arguments first one is the name of RCU flavour, second one is a user id which triggeres synchronize_rcu_normal() and last one is an event. There are two traces in the synchronize_rcu_normal(). On entry, when a new request is registered and on exit point when request is completed. Please note, CONFIG_RCU_TRACE=y is required to activate traces. Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com> --- include/trace/events/rcu.h | 27 +++++++++++++++++++++++++++ kernel/rcu/tree.c | 7 ++++++- 2 files changed, 33 insertions(+), 1 deletion(-)