rcu: Event-trace markers for computing RCU CPU utilization (300df91c) · Commits · 戴 / test

include/trace/events/rcu.h

+53 −20

Original line number	Diff line number	Diff line
		@@ -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_utilization,

		TP_PROTO(char *s),

		TP_ARGS(s),

		TP_STRUCT__entry(
		__field(char *, s)
		),

		TP_fast_assign(
		__entry->s = s;
		),

		TP_printk("%s", __entry->s)
		);

		/*
		* 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 callbacks_ready, int blimit),
		TP_PROTO(long qlen, int blimit),

		TP_ARGS(callbacks_ready, blimit),
		TP_ARGS(qlen, blimit),

		TP_STRUCT__entry(
		__field( long, callbacks_ready )
		__field(long, qlen)
		__field(int, blimit)
		),

		TP_fast_assign(
		__entry->callbacks_ready = callbacks_ready;
		__entry->qlen = qlen;
		__entry->blimit = blimit;
		),

		TP_printk("CBs=%ld bl=%d", __entry->callbacks_ready, __entry->blimit)
		TP_printk("CBs=%ld bl=%d", __entry->qlen, __entry->blimit)
		);

		/*
		* Tracepoint for the invocation of a single RCU callback
		* 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,

		@@ -51,7 +80,10 @@ TRACE_EVENT(rcu_invoke_callback,
		);

		/*
		* 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,

		@@ -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,

kernel/rcutree.c

+15 −1

Original line number	Diff line number	Diff line
		@@ -184,8 +184,10 @@ void rcu_bh_qs(int cpu)
		*/
		void rcu_note_context_switch(int cpu)
		{
		trace_rcu_utilization("Start context switch");
		rcu_sched_qs(cpu);
		rcu_preempt_note_context_switch(cpu);
		trace_rcu_utilization("End context switch");
		}
		EXPORT_SYMBOL_GPL(rcu_note_context_switch);

		@@ -1275,6 +1277,7 @@ static void rcu_do_batch(struct rcu_state rsp, struct rcu_data rdp)
		*/
		void rcu_check_callbacks(int cpu, int user)
		{
		trace_rcu_utilization("Start scheduler-tick");
		if (user \|\|
		(idle_cpu(cpu) && rcu_scheduler_active &&
		!in_softirq() && hardirq_count() <= (1 << HARDIRQ_SHIFT))) {
		@@ -1308,6 +1311,7 @@ void rcu_check_callbacks(int cpu, int user)
		rcu_preempt_check_callbacks(cpu);
		if (rcu_pending(cpu))
		invoke_rcu_core();
		trace_rcu_utilization("End scheduler-tick");
		}

		#ifdef CONFIG_SMP
		@@ -1369,10 +1373,14 @@ static void force_quiescent_state(struct rcu_state *rsp, int relaxed)
		unsigned long flags;
		struct rcu_node *rnp = rcu_get_root(rsp);

		if (!rcu_gp_in_progress(rsp))
		trace_rcu_utilization("Start fqs");
		if (!rcu_gp_in_progress(rsp)) {
		trace_rcu_utilization("End fqs");
		return; /* No grace period in progress, nothing to force. */
		}
		if (!raw_spin_trylock_irqsave(&rsp->fqslock, flags)) {
		rsp->n_force_qs_lh++; /* Inexact, can lose counts. Tough! */
		trace_rcu_utilization("End fqs");
		return; /* Someone else is already on the job. */
		}
		if (relaxed && ULONG_CMP_GE(rsp->jiffies_force_qs, jiffies))
		@@ -1421,11 +1429,13 @@ static void force_quiescent_state(struct rcu_state *rsp, int relaxed)
		raw_spin_unlock(&rsp->fqslock); /* irqs remain disabled */
		rsp->fqs_need_gp = 0;
		rcu_start_gp(rsp, flags); /* releases rnp->lock */
		trace_rcu_utilization("End fqs");
		return;
		}
		raw_spin_unlock(&rnp->lock); /* irqs remain disabled */
		unlock_fqs_ret:
		raw_spin_unlock_irqrestore(&rsp->fqslock, flags);
		trace_rcu_utilization("End fqs");
		}

		#else /* #ifdef CONFIG_SMP */
		@@ -1481,6 +1491,7 @@ __rcu_process_callbacks(struct rcu_state rsp, struct rcu_data rdp)
		*/
		static void rcu_process_callbacks(struct softirq_action *unused)
		{
		trace_rcu_utilization("Start RCU core");
		__rcu_process_callbacks(&rcu_sched_state,
		&__get_cpu_var(rcu_sched_data));
		__rcu_process_callbacks(&rcu_bh_state, &__get_cpu_var(rcu_bh_data));
		@@ -1488,6 +1499,7 @@ static void rcu_process_callbacks(struct softirq_action *unused)

		/* If we are last CPU on way to dyntick-idle mode, accelerate it. */
		rcu_needs_cpu_flush();
		trace_rcu_utilization("End RCU core");
		}

		/*
		@@ -1910,6 +1922,7 @@ static int __cpuinit rcu_cpu_notify(struct notifier_block *self,
		struct rcu_data *rdp = per_cpu_ptr(rcu_state->rda, cpu);
		struct rcu_node *rnp = rdp->mynode;

		trace_rcu_utilization("Start CPU hotplug");
		switch (action) {
		case CPU_UP_PREPARE:
		case CPU_UP_PREPARE_FROZEN:
		@@ -1945,6 +1958,7 @@ static int __cpuinit rcu_cpu_notify(struct notifier_block *self,
		default:
		break;
		}
		trace_rcu_utilization("End CPU hotplug");
		return NOTIFY_OK;
		}

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