#!/usr/bin/bpftrace
/*
 * Trace Runtime of a GNU Radio block
 * 		For Linux, uses bpftrace and eBPF.
 *
 * Usage: 
 * 
 * 0. Install GNU Radio and bpftrace
 * 1. change the path to the library you want to probe
 *    (in this example, that was /path/to/my/libgnuradio-filter.so).
 *    If the library is installed in a system-default location, the
 *    name alone should suffice.
 * 2. change the C++ name of the work function you want to probe
 *    (in this example,
 *    gr::filter::fir_filter_blk_impl<float, float, float>::work)
 * 3. run this script as root:
 *    `sudo bpftrace thisscript.bt | tee statistics.txt` 
 * 4. Start your GNU Radio flow graph
 * 5. Marvel at the numbers you're getting!
 *
 * Copyright (c) 2021 Tao Xu (as sslsnoop.bt)
 * Copyright (c) 2024 Marcus Müller 
 * Licensed under the Apache License, Version 2.0 (the "License")
 *
 * 15-Dec-2021	Tao Xu	created this.
 * 14-Feb-2024  Marcus Müller  adopted to GR
 */

BEGIN
{
	printf("Tracing work call runtimes... Hit Ctrl-C to end.\n");
	printf("NOTE: this assumes that the block never manually calls produce(), but returns the items produced in each call!\n");
	printf("%8s %7s %5s\n", "TID", "Δt [ns]", "Ret (s/S)");
}

uprobe:/path/to/my/libgnuradio-filter.so:cpp:"gr::filter::fir_filter_blk_impl<float, float, float>::work"
{
  @start_work[tid] = nsecs;
}

uretprobe:/path/to/my/libgnuradio-filter.so:cpp:"gr::filter::fir_filter_blk_impl<float, float, float>::work"
/@start_work[tid] != 0/
{
	printf("%-8d %7u %5d\n", tid, (nsecs - @start_work[tid]), 1e9 * retval / (nsecs - @start_work[tid]));
	delete(@start_work[tid]);
}