Messages in this thread Patch in this message | | | From | Julien Desfossez <> | Subject | [RFC PATCH 5/6] tracing: extend scheduling tracepoints | Date | Fri, 16 Sep 2016 17:09:07 -0400 |
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Create alternate versions of the sched_switch, sched_waking and sched_process_fork tracepoint probes to output priority-related fields and PI top-waiter if any.
This uses the TRACE_EVENT_MAP macro, so the instrumented code and the already existing tracepoints are untouched.
We only expose the priority-related fields visible from userspace, leaving out the "prio" value which should really be a kernel-internal representation of the task priority, and must be expected to be eventually deprecated. The values output are the effective values, not necessarily the normal values.
We also output the comm and PID of the process blocked by the task if it is in a PI situation. These fields allow to quickly identify the PI situations without requiring to keep track of all the sched_pi_setprio/sched_pi_update_prio events and state.
The values traced are the effective values, which may differ from the thread normal values in PI scenarios.
Here is an example of the output from these new probes: sched_process_fork_prio: comm=bash, pid=1988, child_comm=bash, child_pid=2129, child_policy=SCHED_NORMAL, child_nice=0, child_rt_priority=0, child_dl_runtime=0, child_dl_deadline=0, child_dl_period=0
No PI: sched_switch_prio: prev_comm=swapper/6, prev_pid=0, prev_policy=SCHED_NORMAL, prev_nice=0, prev_rt_priority=0, prev_dl_runtime=0, prev_dl_deadline=0, prev_dl_period=0, prev_state=R, prev_top_waiter_comm=, prev_top_waiter_pid=-1 ==> next_comm=bash, next_pid=3817, next_policy=SCHED_NORMAL, next_nice=0, next_rt_priority=0, next_dl_runtime=0, next_dl_deadline=0, next_dl_period=0, next_top_waiter_comm=, next_top_waiter_pid=-1
sched_waking_prio: comm=migration/6, pid=38, target_cpu=006, policy=SCHED_FIFO, nice=0, rt_priority=99, dl_runtime=0, dl_deadline=0, dl_period=0, top_waiter_comm=, top_waiter_pid=-1
PI: sched_switch_prio: prev_comm=swapper/1, prev_pid=0, prev_policy=SCHED_NORMAL, prev_nice=0, prev_rt_priority=0, prev_dl_runtime=0, prev_dl_deadline=0, prev_dl_period=0, prev_state=R, prev_top_waiter_comm=, prev_top_waiter_pid=-1 ==> next_comm=lowprio1, next_pid=3818, next_policy=SCHED_NORMAL, next_nice=0, next_rt_priority=90, next_dl_runtime=0, next_dl_deadline=0, next_dl_period=0, next_top_waiter_comm=highprio0, next_top_waiter_pid=3820
sched_waking_prio: comm=lowprio1, pid=3818, target_cpu=001, policy=SCHED_FIFO, nice=0, rt_priority=90, dl_runtime=0, dl_deadline=0, dl_period=0, top_waiter_comm=highprio0, top_waiter_pid=3820
Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt (Red Hat) <rostedt@goodmis.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@redhat.com> Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Signed-off-by: Julien Desfossez <jdesfossez@efficios.com> --- include/trace/events/sched.h | 222 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 222 insertions(+)
diff --git a/include/trace/events/sched.h b/include/trace/events/sched.h index bc695e4..11b3358 100644 --- a/include/trace/events/sched.h +++ b/include/trace/events/sched.h @@ -131,6 +131,64 @@ TP_PROTO(struct task_struct *p), TP_ARGS(p)); +TRACE_EVENT_MAP(sched_waking, sched_waking_prio, + + TP_PROTO(struct task_struct *p), + + TP_ARGS(p), + + TP_STRUCT__entry( + __array( char, comm, TASK_COMM_LEN ) + __field( pid_t, pid ) + __field( int, target_cpu ) + __field( unsigned int, policy ) + __field( int, nice ) + __field( unsigned int, rt_priority ) + __field( u64, dl_runtime ) + __field( u64, dl_deadline ) + __field( u64, dl_period ) + __array( char, top_waiter_comm, TASK_COMM_LEN ) + __field( pid_t, top_waiter_pid ) + ), + + TP_fast_assign( + struct task_struct *top_waiter = rt_mutex_get_top_task(p); + + memcpy(__entry->comm, p->comm, TASK_COMM_LEN); + __entry->pid = p->pid; + __entry->target_cpu = task_cpu(p); + __entry->policy = rt_mutex_get_effective_policy( + p->policy, p->prio); + __entry->nice = task_nice(p); + __entry->rt_priority = rt_mutex_get_effective_rt_prio( + p->prio); + __entry->dl_runtime = dl_prio(p->prio) ? + p->dl.dl_runtime : 0; + __entry->dl_deadline = dl_prio(p->prio) ? + p->dl.dl_deadline : 0; + __entry->dl_period = dl_prio(p->prio) ? + p->dl.dl_period : 0; + if (top_waiter) { + memcpy(__entry->top_waiter_comm, top_waiter->comm, + TASK_COMM_LEN); + __entry->top_waiter_pid = top_waiter->pid; + } else { + __entry->top_waiter_comm[0] = '\0'; + __entry->top_waiter_pid = -1; + } + ), + + TP_printk("comm=%s, pid=%d, target_cpu=%03d, policy=%s, " + "nice=%d, rt_priority=%u, dl_runtime=%Lu, " + "dl_deadline=%Lu, dl_period=%Lu, " + "top_waiter_comm=%s, top_waiter_pid=%d", + __entry->comm, __entry->pid, __entry->target_cpu, + __print_symbolic(__entry->policy, SCHEDULING_POLICY), + __entry->nice, __entry->rt_priority, __entry->dl_runtime, + __entry->dl_deadline, __entry->dl_period, + __entry->top_waiter_comm, __entry->top_waiter_pid) +); + #ifdef CREATE_TRACE_POINTS static inline long __trace_sched_switch_state(bool preempt, struct task_struct *p) { @@ -190,6 +248,121 @@ static inline long __trace_sched_switch_state(bool preempt, struct task_struct * ); /* + * Tracepoint for task switches, performed by the scheduler: + */ +TRACE_EVENT_MAP(sched_switch, sched_switch_prio, + TP_PROTO(bool preempt, + struct task_struct *prev, + struct task_struct *next), + + TP_ARGS(preempt, prev, next), + + TP_STRUCT__entry( + __array( char, prev_comm, TASK_COMM_LEN ) + __field( pid_t, prev_pid ) + __field( long, prev_state ) + __field( unsigned int, prev_policy ) + __field( int, prev_nice ) + __field( unsigned int, prev_rt_priority ) + __field( u64, prev_dl_runtime ) + __field( u64, prev_dl_deadline ) + __field( u64, prev_dl_period ) + __array( char, prev_top_waiter_comm, TASK_COMM_LEN ) + __field( pid_t, prev_top_waiter_pid ) + __array( char, next_comm, TASK_COMM_LEN ) + __field( pid_t, next_pid ) + __field( unsigned int, next_policy ) + __field( int, next_nice ) + __field( unsigned int, next_rt_priority ) + __field( u64, next_dl_runtime ) + __field( u64, next_dl_deadline ) + __field( u64, next_dl_period ) + __array( char, next_top_waiter_comm, TASK_COMM_LEN ) + __field( pid_t, next_top_waiter_pid ) + ), + + TP_fast_assign( + struct task_struct *prev_top = rt_mutex_get_top_task(prev); + struct task_struct *next_top = rt_mutex_get_top_task(next); + + memcpy(__entry->prev_comm, prev->comm, TASK_COMM_LEN); + __entry->prev_pid = prev->pid; + __entry->prev_state = __trace_sched_switch_state( + preempt, prev); + __entry->prev_policy = rt_mutex_get_effective_policy( + prev->policy, prev->prio); + __entry->prev_nice = task_nice(prev); + __entry->prev_rt_priority = rt_mutex_get_effective_rt_prio( + prev->prio); + __entry->prev_dl_runtime = dl_prio(prev->prio) ? + prev->dl.dl_runtime : 0; + __entry->prev_dl_deadline = dl_prio(prev->prio) ? + prev->dl.dl_deadline : 0; + __entry->prev_dl_period = dl_prio(prev->prio) ? + prev->dl.dl_period : 0; + if (prev_top) { + memcpy(__entry->prev_top_waiter_comm, prev_top->comm, + TASK_COMM_LEN); + __entry->prev_top_waiter_pid = prev_top->pid; + } else { + __entry->prev_top_waiter_comm[0] = '\0'; + __entry->prev_top_waiter_pid = -1; + } + + memcpy(__entry->next_comm, next->comm, TASK_COMM_LEN); + __entry->next_pid = next->pid; + __entry->next_policy = rt_mutex_get_effective_policy( + next->policy, prev->prio); + __entry->next_nice = task_nice(next); + __entry->next_rt_priority = rt_mutex_get_effective_rt_prio( + next->prio); + __entry->next_dl_runtime = dl_prio(next->prio) ? + next->dl.dl_runtime : 0; + __entry->next_dl_deadline = dl_prio(next->prio) ? + next->dl.dl_deadline : 0; + __entry->next_dl_period = dl_prio(next->prio) ? + next->dl.dl_period : 0; + if (next_top) { + memcpy(__entry->next_top_waiter_comm, next_top->comm, + TASK_COMM_LEN); + __entry->next_top_waiter_pid = next_top->pid; + } else { + __entry->next_top_waiter_comm[0] = '\0'; + __entry->next_top_waiter_pid = -1; + } + ), + + TP_printk("prev_comm=%s, prev_pid=%d, prev_policy=%s, prev_nice=%d, " + "prev_rt_priority=%u, prev_dl_runtime=%Lu, " + "prev_dl_deadline=%Lu, prev_dl_period=%Lu, " + "prev_state=%s%s, prev_top_waiter_comm=%s, " + "prev_top_waiter_pid=%d ==> next_comm=%s, next_pid=%d, " + "next_policy=%s, next_nice=%d, next_rt_priority=%u, " + "next_dl_runtime=%Lu, next_dl_deadline=%Lu, " + "next_dl_period=%Lu, next_top_waiter_comm=%s, " + "next_top_waiter_pid=%d", + __entry->prev_comm, __entry->prev_pid, + __print_symbolic(__entry->prev_policy, SCHEDULING_POLICY), + __entry->prev_nice, __entry->prev_rt_priority, + __entry->prev_dl_runtime, __entry->prev_dl_deadline, + __entry->prev_dl_period, + __entry->prev_state & (TASK_STATE_MAX-1) ? + __print_flags(__entry->prev_state & (TASK_STATE_MAX-1), "|", + { 1, "S"} , { 2, "D" }, { 4, "T" }, { 8, "t" }, + { 16, "Z" }, { 32, "X" }, { 64, "x" }, + { 128, "K" }, { 256, "W" }, { 512, "P" }, + { 1024, "N" }) : "R", + __entry->prev_state & TASK_STATE_MAX ? "+" : "", + __entry->prev_top_waiter_comm, __entry->prev_top_waiter_pid, + __entry->next_comm, __entry->next_pid, + __print_symbolic(__entry->next_policy, SCHEDULING_POLICY), + __entry->next_nice, __entry->next_rt_priority, + __entry->next_dl_runtime, __entry->next_dl_deadline, + __entry->next_dl_period, __entry->next_top_waiter_comm, + __entry->next_top_waiter_pid) +); + +/* * Tracepoint for a task being migrated: */ TRACE_EVENT(sched_migrate_task, @@ -316,6 +489,55 @@ static inline long __trace_sched_switch_state(bool preempt, struct task_struct * __entry->child_comm, __entry->child_pid) ); +TRACE_EVENT_MAP(sched_process_fork, sched_process_fork_prio, + + TP_PROTO(struct task_struct *parent, struct task_struct *child), + + TP_ARGS(parent, child), + + TP_STRUCT__entry( + __array( char, parent_comm, TASK_COMM_LEN ) + __field( pid_t, parent_pid ) + __array( char, child_comm, TASK_COMM_LEN ) + __field( pid_t, child_pid ) + __field( unsigned int, child_policy ) + __field( int, child_nice ) + __field( unsigned int, child_rt_priority ) + __field( u64, child_dl_runtime ) + __field( u64, child_dl_deadline ) + __field( u64, child_dl_period ) + ), + + TP_fast_assign( + memcpy(__entry->parent_comm, parent->comm, TASK_COMM_LEN); + __entry->parent_pid = parent->pid; + memcpy(__entry->child_comm, child->comm, TASK_COMM_LEN); + __entry->child_pid = child->pid; + __entry->child_policy = rt_mutex_get_effective_policy( + child->policy, child->prio); + __entry->child_nice = task_nice(child); + __entry->child_rt_priority = rt_mutex_get_effective_rt_prio( + child->prio); + __entry->child_dl_runtime = dl_prio(child->prio) ? + child->dl.dl_runtime : 0; + __entry->child_dl_deadline = dl_prio(child->prio) ? + child->dl.dl_deadline : 0; + __entry->child_dl_period = dl_prio(child->prio) ? + child->dl.dl_period : 0; + ), + + TP_printk("comm=%s, pid=%d, child_comm=%s, child_pid=%d, " + "child_policy=%s, child_nice=%d, " + "child_rt_priority=%u, child_dl_runtime=%Lu, " + "child_dl_deadline=%Lu, child_dl_period=%Lu", + __entry->parent_comm, __entry->parent_pid, + __entry->child_comm, __entry->child_pid, + __print_symbolic(__entry->child_policy, SCHEDULING_POLICY), + __entry->child_nice, __entry->child_rt_priority, + __entry->child_dl_runtime, __entry->child_dl_deadline, + __entry->child_dl_period) +); + /* * Tracepoint for exec: */ -- 1.9.1
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