This adds an option '-m/--buffer-size' to allow us set the size of per-cpu
tracing buffer.
Committer testing:
Before running with this option:
# find /sys/kernel/tracing/ -name buffer_size_kb | xargs cat
1408
1408
1408
1408
1408
1408
1408
1408
1408
#
Then, run:
# perf ftrace -m 2048K | head -10
2) | mutex_unlock() {
2) ==========> |
2) | smp_irq_work_interrupt() {
2) | irq_enter() {
2) 0.121 us | rcu_irq_enter();
2) 0.128 us | irqtime_account_irq();
2) 0.719 us | }
2) | __wake_up() {
2) | __wake_up_common_lock() {
2) 0.105 us | _raw_spin_lock_irqsave();
#
Now look at those tracefs knobs:
# find /sys/kernel/tracing/ -name buffer_size_kb | xargs cat
2048
2048
2048
2048
2048
2048
2048
2048
2048
#
This should be similar to the -m option in the other perf tools, such as
'perf record', 'perf trace', etc.
Signed-off-by: Changbin Du <changbin.du@gmail.com>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt (VMware) <rostedt@goodmis.org>
Link: http://lore.kernel.org/lkml/20200808023141.14227-5-changbin.du@gmail.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>