Current File : //usr/share/systemtap/examples/profiling/fntimes.stp
#!/usr/bin/stap
# usage: fntimes.stp FUNCTIONPROBE
# e.g. fntimes.stp 'module("ext4").function("*")'
global mincount = 100 # training: beneath this number of hits, only collect data
global note_percent = 250 # percent beyond maximum-so-far to generate report for
function time() { return gettimeofday_us() } # time measurement function
global times
function check(t) # t: elapsed time
{
if (@count(times[ppfunc()]) >= mincount
&& t >= @max(times[ppfunc()]) * note_percent / 100) { # also consider @avg()
printf("function %s well over %s time (%d vs %d), duration variance %d s^2\n",
ppfunc(), "maximum", t, @max(times[ppfunc()]), @variance(times[ppfunc()], 3))
# also consider: print_backtrace()
}
times[ppfunc()] <<< t # (increments @count, updates @max)
}
probe $1.return { check(time()-@entry(time())) }
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