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authorLingutla Chandrasekhar <clingutla@codeaurora.org>2023-04-07 23:05:26 +0000
committerThomas Gleixner <tglx@linutronix.de>2023-04-15 10:17:16 +0200
commitf4bf3ca2e5cba655824b6e0893a98dfb33ed24e5 (patch)
tree7758cc32a4ac78cb54b250c16fe1bc8d83efc029 /kernel/softirq.c
parent7e364e56293bb98cae1b55fd835f5991c4e96e7d (diff)
softirq: Add trace points for tasklet entry/exit
Tasklets are supposed to finish their work quickly and should not block the current running process, but it is not guaranteed that they do so. Currently softirq_entry/exit can be used to analyse the total tasklets execution time, but that's not helpful to track individual tasklets execution time. That makes it hard to identify tasklet functions, which take more time than expected. Add tasklet_entry/exit trace point support to track individual tasklet execution. Trivial usage example: # echo 1 > /sys/kernel/debug/tracing/events/irq/tasklet_entry/enable # echo 1 > /sys/kernel/debug/tracing/events/irq/tasklet_exit/enable # cat /sys/kernel/debug/tracing/trace # tracer: nop # # entries-in-buffer/entries-written: 4/4 #P:4 # # _-----=> irqs-off/BH-disabled # / _----=> need-resched # | / _---=> hardirq/softirq # || / _--=> preempt-depth # ||| / _-=> migrate-disable # |||| / delay # TASK-PID CPU# ||||| TIMESTAMP FUNCTION # | | | ||||| | | <idle>-0 [003] ..s1. 314.011428: tasklet_entry: tasklet=0xffffa01ef8db2740 function=tcp_tasklet_func <idle>-0 [003] ..s1. 314.011432: tasklet_exit: tasklet=0xffffa01ef8db2740 function=tcp_tasklet_func <idle>-0 [003] ..s1. 314.017369: tasklet_entry: tasklet=0xffffa01ef8db2740 function=tcp_tasklet_func <idle>-0 [003] ..s1. 314.017371: tasklet_exit: tasklet=0xffffa01ef8db2740 function=tcp_tasklet_func Signed-off-by: Lingutla Chandrasekhar <clingutla@codeaurora.org> Signed-off-by: J. Avila <elavila@google.com> Signed-off-by: John Stultz <jstultz@google.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org> Link: https://lore.kernel.org/r/20230407230526.1685443-1-jstultz@google.com [elavila: Port to android-mainline] [jstultz: Rebased to upstream, cut unused trace points, added comments for the tracepoints, reworded commit]
Diffstat (limited to 'kernel/softirq.c')
-rw-r--r--kernel/softirq.c9
1 files changed, 7 insertions, 2 deletions
diff --git a/kernel/softirq.c b/kernel/softirq.c
index c8a6913c067d..1b725510dd0f 100644
--- a/kernel/softirq.c
+++ b/kernel/softirq.c
@@ -793,10 +793,15 @@ static void tasklet_action_common(struct softirq_action *a,
if (tasklet_trylock(t)) {
if (!atomic_read(&t->count)) {
if (tasklet_clear_sched(t)) {
- if (t->use_callback)
+ if (t->use_callback) {
+ trace_tasklet_entry(t, t->callback);
t->callback(t);
- else
+ trace_tasklet_exit(t, t->callback);
+ } else {
+ trace_tasklet_entry(t, t->func);
t->func(t->data);
+ trace_tasklet_exit(t, t->func);
+ }
}
tasklet_unlock(t);
continue;