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linux/include/trace
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Sumanth Gavini 4443fc58fc softirq: Add trace points for tasklet entry/exit 
commit f4bf3ca2e5 upstream.

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]

The intention is to keep the stable branch in sync with upstream fixes
and improve observability without introducing new functionality.

Signed-off-by: Sumanth Gavini <sumanth.gavini@yahoo.com>

Changes in V2:
- No code changes
- Link to V1: https://lore.kernel.org/all/20250812161755.609600-1-sumanth.gavini@yahoo.com/
- Updated the comment msg before the signed-off-by

Signed-off-by: Sasha Levin <sashal@kernel.org>
History 2025-12-07 06:12:34 +09:00
..
events softirq: Add trace points for tasklet entry/exit 2025-12-07 06:12:34 +09:00
misc NFSD: add CB_RECALL_ANY tracepoints 2024-03-06 14:45:17 +00:00
stages tracing: Remove pointer (asterisk) and brackets from cpumask_t field 2025-05-02 07:47:10 +02:00
bpf_probe.h tracing: Add __cpumask to denote a trace event field that is a cpumask_t 2025-05-02 07:46:49 +02:00
define_custom_trace.h tracing: Add TRACE_CUSTOM_EVENT() macro 2022-03-11 11:49:24 -05:00
define_trace.h tracepoint: Optimize using static_call() 2020-09-01 09:58:06 +02:00
perf.h tracing: Add __cpumask to denote a trace event field that is a cpumask_t 2025-05-02 07:46:49 +02:00
syscall.h tracepoints: Migrate to use SYSCALL_WORK flag 2020-11-16 21:53:15 +01:00
trace_custom_events.h tracing: Rename the staging files for trace_events 2022-04-02 08:40:04 -04:00
trace_events.h tracing/ftrace: disable preemption in syscall probe 2024-12-14 19:54:45 +01:00