From f4bf3ca2e5cba655824b6e0893a98dfb33ed24e5 Mon Sep 17 00:00:00 2001 From: Lingutla Chandrasekhar Date: Fri, 7 Apr 2023 23:05:26 +0000 Subject: 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 # | | | ||||| | | -0 [003] ..s1. 314.011428: tasklet_entry: tasklet=0xffffa01ef8db2740 function=tcp_tasklet_func -0 [003] ..s1. 314.011432: tasklet_exit: tasklet=0xffffa01ef8db2740 function=tcp_tasklet_func -0 [003] ..s1. 314.017369: tasklet_entry: tasklet=0xffffa01ef8db2740 function=tcp_tasklet_func -0 [003] ..s1. 314.017371: tasklet_exit: tasklet=0xffffa01ef8db2740 function=tcp_tasklet_func Signed-off-by: Lingutla Chandrasekhar Signed-off-by: J. Avila Signed-off-by: John Stultz Signed-off-by: Thomas Gleixner Reviewed-by: Steven Rostedt (Google) 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] --- kernel/softirq.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) (limited to 'kernel') 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; -- cgit v1.2.3 From 803235982b8c086184d04798d9079d236f352f88 Mon Sep 17 00:00:00 2001 From: John Keeping Date: Thu, 6 Apr 2023 19:08:57 +0100 Subject: genirq: Update affinity of secondary threads For interrupts with secondary threads, the affinity is applied when the thread is created but if the interrupts affinity is changed later only the primary thread is updated. Update the secondary thread's affinity as well to keep all the interrupts activity on the assigned CPUs. Signed-off-by: John Keeping Signed-off-by: Thomas Gleixner Link: https://lore.kernel.org/r/20230406180857.588682-1-john@metanate.com --- kernel/irq/manage.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c index 8ce75495e04f..d2742af0f0fd 100644 --- a/kernel/irq/manage.c +++ b/kernel/irq/manage.c @@ -189,9 +189,12 @@ void irq_set_thread_affinity(struct irq_desc *desc) { struct irqaction *action; - for_each_action_of_desc(desc, action) + for_each_action_of_desc(desc, action) { if (action->thread) set_bit(IRQTF_AFFINITY, &action->thread_flags); + if (action->secondary && action->secondary->thread) + set_bit(IRQTF_AFFINITY, &action->secondary->thread_flags); + } } #ifdef CONFIG_GENERIC_IRQ_EFFECTIVE_AFF_MASK -- cgit v1.2.3