rcu: Event-trace markers for computing RCU CPU utilization

This commit adds the trace_rcu_utilization() marker that is to be
used to allow postprocessing scripts compute RCU's CPU utilization,
give or take event-trace overhead.  Note that we do not include RCU's
dyntick-idle interface because event tracing requires RCU protection,
which is not available in dyntick-idle mode.

Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
This commit is contained in:
Paul E. McKenney
2011-06-18 22:26:31 -07:00
committed by Paul E. McKenney
parent 29c00b4a1d
commit 300df91ca9
2 changed files with 69 additions and 22 deletions

View File

@ -7,29 +7,58 @@
#include <linux/tracepoint.h>
/*
* Tracepoint for calling rcu_do_batch, performed to start callback invocation:
* Tracepoint for start/end markers used for utilization calculations.
* By convention, the string is of the following forms:
*
* "Start <activity>" -- Mark the start of the specified activity,
* such as "context switch". Nesting is permitted.
* "End <activity>" -- Mark the end of the specified activity.
*/
TRACE_EVENT(rcu_batch_start,
TRACE_EVENT(rcu_utilization,
TP_PROTO(long callbacks_ready, int blimit),
TP_PROTO(char *s),
TP_ARGS(callbacks_ready, blimit),
TP_ARGS(s),
TP_STRUCT__entry(
__field( long, callbacks_ready )
__field( int, blimit )
__field(char *, s)
),
TP_fast_assign(
__entry->callbacks_ready = callbacks_ready;
__entry->blimit = blimit;
__entry->s = s;
),
TP_printk("CBs=%ld bl=%d", __entry->callbacks_ready, __entry->blimit)
TP_printk("%s", __entry->s)
);
/*
* Tracepoint for the invocation of a single RCU callback
* Tracepoint for marking the beginning rcu_do_batch, performed to start
* RCU callback invocation. The first argument is the total number of
* callbacks (including those that are not yet ready to be invoked),
* and the second argument is the current RCU-callback batch limit.
*/
TRACE_EVENT(rcu_batch_start,
TP_PROTO(long qlen, int blimit),
TP_ARGS(qlen, blimit),
TP_STRUCT__entry(
__field(long, qlen)
__field(int, blimit)
),
TP_fast_assign(
__entry->qlen = qlen;
__entry->blimit = blimit;
),
TP_printk("CBs=%ld bl=%d", __entry->qlen, __entry->blimit)
);
/*
* Tracepoint for the invocation of a single RCU callback function.
* The argument is a pointer to the RCU callback itself.
*/
TRACE_EVENT(rcu_invoke_callback,
@ -38,20 +67,23 @@ TRACE_EVENT(rcu_invoke_callback,
TP_ARGS(rhp),
TP_STRUCT__entry(
__field( void *, rhp )
__field( void *, func )
__field(void *, rhp)
__field(void *, func)
),
TP_fast_assign(
__entry->rhp = rhp;
__entry->func = rhp->func;
__entry->rhp = rhp;
__entry->func = rhp->func;
),
TP_printk("rhp=%p func=%pf", __entry->rhp, __entry->func)
);
/*
* Tracepoint for the invocation of a single RCU kfree callback
* Tracepoint for the invocation of a single RCU callback of the special
* kfree() form. The first argument is a pointer to the RCU callback
* and the second argument is the offset of the callback within the
* enclosing RCU-protected data structure.
*/
TRACE_EVENT(rcu_invoke_kfree_callback,
@ -60,12 +92,12 @@ TRACE_EVENT(rcu_invoke_kfree_callback,
TP_ARGS(rhp, offset),
TP_STRUCT__entry(
__field(void *, rhp )
__field(unsigned long, offset )
__field(void *, rhp)
__field(unsigned long, offset)
),
TP_fast_assign(
__entry->rhp = rhp;
__entry->rhp = rhp;
__entry->offset = offset;
),
@ -73,7 +105,8 @@ TRACE_EVENT(rcu_invoke_kfree_callback,
);
/*
* Tracepoint for leaving rcu_do_batch, performed after callback invocation:
* Tracepoint for exiting rcu_do_batch after RCU callbacks have been
* invoked. The first argument is the number of callbacks actually invoked.
*/
TRACE_EVENT(rcu_batch_end,
@ -82,11 +115,11 @@ TRACE_EVENT(rcu_batch_end,
TP_ARGS(callbacks_invoked),
TP_STRUCT__entry(
__field( int, callbacks_invoked )
__field(int, callbacks_invoked)
),
TP_fast_assign(
__entry->callbacks_invoked = callbacks_invoked;
__entry->callbacks_invoked = callbacks_invoked;
),
TP_printk("CBs-invoked=%d", __entry->callbacks_invoked)