#!/usr/bin/env bpftrace
/* 
reference: https://github.com/bpftrace/bpftrace/blob/master/man/adoc/bpftrace.adoc
prepare: yum install bpftrace
example: ./latency.bt xxx.so func1 func2
supported functions: bpftrace -l 'uprobe:xxx.so'
*/

BEGIN
{
}

uprobe:$1:$2
{
    @t_start[tid] = nsecs;
}

uretprobe:$1:$3
/@t_start[tid]/
{
    $t_dur = nsecs - @t_start[tid];
    @t_avg = avg($t_dur);

    //@t_hist = lhist($t_dur, 0, 4000, 100);
    @t_hist = hist($t_dur);

    delete(@t_start[tid]);
}

END
{
    printf("\n\n%s -> %s \n", str($2), str($3));
    printf("average time(nsec):");
    print(@t_avg);

    clear(@t_avg);
    clear(@t_start);
}