# 
# cat prctl-perf.c 
#include <sys/prctl.h>

void loop_events_disabled() {
    volatile int x;
    int i;
    for (i = 0; i < 1000000000; i++)
        x = i;
    return;
}

void loop_events_enabled() {
    volatile int x;
    int i;
    for (i = 0; i < 1000000000; i++)
        x = i;
    return;
}

int main(int argc, char **argv) {
    prctl(PR_TASK_PERF_EVENTS_ENABLE);
    loop_events_enabled();
    prctl(PR_TASK_PERF_EVENTS_DISABLE);
    loop_events_disabled();
}
# gcc -g prctl-perf.c -o prctl-perf
# 
# perf record /home/acme/c/prctl-perf
[ perf record: Woken up 3 times to write data ]
[ perf record: Captured and wrote 0.562 MB perf.data (14295 samples) ]
# perf report --stdio --no-header --percent-limit 1
# To display the perf.data header info, please use --header/--header-only options.
#
#
# Total Lost Samples: 0
#
# Samples: 14K of event 'cycles'
# Event count (approx.): 15897534555
#
# Overhead  Command     Shared Object     Symbol                             
# ........  ..........  ................  ...................................
#
    49.80%  prctl-perf  prctl-perf        [.] loop_events_enabled
    49.73%  prctl-perf  prctl-perf        [.] loop_events_disabled


#
# (Tip: Create an archive with symtabs to analyse on other machine: perf archive)
#
# 
# perf probe -x /home/acme/c/prctl-perf loop_events_enabled
Added new event:
  probe_prctl:loop_events_enabled (on loop_events_enabled in /home/acme/c/prctl-perf)

You can now use it in all perf tools, such as:

	perf record -e probe_prctl:loop_events_enabled -aR sleep 1

# perf probe -x /home/acme/c/prctl-perf loop_events_disabled
Added new event:
  probe_prctl:loop_events_disabled (on loop_events_disabled in /home/acme/c/prctl-perf)

You can now use it in all perf tools, such as:

	perf record -e probe_prctl:loop_events_disabled -aR sleep 1

# perf probe -l
  probe_prctl:loop_events_disabled (on loop_events_disabled@/home/acme/c/prctl-perf.c in /home/acme/c/prctl-perf)
  probe_prctl:loop_events_enabled (on loop_events_enabled@/home/acme/c/prctl-perf.c in /home/acme/c/prctl-perf)
# 
# perf record -e cycles,probe_prctl:* /home/acme/c/prctl-perf
[ perf record: Woken up 3 times to write data ]
[ perf record: Captured and wrote 0.678 MB perf.data (14394 samples) ]
# perf evlist
cycles
probe_prctl:loop_events_disabled
probe_prctl:loop_events_enabled
# Tip: use 'perf evlist --trace-fields' to show fields for tracepoint events
# perf report --stdio --no-header --percent-limit 1 --switch-on probe_prctl:loop_events_enabled --switch-off probe_prctl:loop_events_disabled
# To display the perf.data header info, please use --header/--header-only options.
#
#
# Total Lost Samples: 0
#
# Samples: 7K of event 'cycles'
# Event count (approx.): 7909562953
#
# Overhead  Command     Shared Object     Symbol                 
# ........  ..........  ................  .......................
#
    99.99%  prctl-perf  prctl-perf        [.] loop_events_enabled


# perf report --stdio --no-header --percent-limit 1
# To display the perf.data header info, please use --header/--header-only options.
#
#
# Total Lost Samples: 0
#
# Samples: 14K of event 'cycles'
# Event count (approx.): 15898142470
#
# Overhead  Command     Shared Object     Symbol                            
# ........  ..........  ................  ..................................
#
    50.25%  prctl-perf  prctl-perf        [.] loop_events_disabled
    49.74%  prctl-perf  prctl-perf        [.] loop_events_enabled


# Samples: 1  of event 'probe_prctl:loop_events_disabled'
# Event count (approx.): 1
#
# Overhead  Command     Shared Object  Symbol                  
# ........  ..........  .............  ........................
#
   100.00%  prctl-perf  prctl-perf     [.] loop_events_disabled


# Samples: 1  of event 'probe_prctl:loop_events_enabled'
# Event count (approx.): 1
#
# Overhead  Command     Shared Object  Symbol                 
# ........  ..........  .............  .......................
#
   100.00%  prctl-perf  prctl-perf     [.] loop_events_enabled

#