reproduction Flowgraph for https://github.com/gnuradio/gnuradio/issues/6698

repro.sh

#!/bin/sh

port=9999

# start FG in background
./repro6698.py -p $port &
grpid=$!
sleep 0.5
perf record -ag -p $grpid &
sleep 2

# connect, pipe away
nc 127.0.0.1 $port &
sleep 10
kill -9 $grpid

repro6698.grc

options:
  parameters:
    author: marcus
    catch_exceptions: 'True'
    category: '[GRC Hier Blocks]'
    cmake_opt: ''
    comment: ''
    copyright: ''
    description: ''
    gen_cmake: 'On'
    gen_linking: dynamic
    generate_options: no_gui
    hier_block_src_path: '.:'
    id: repro6698
    max_nouts: '0'
    output_language: python
    placement: (0,0)
    qt_qss_theme: ''
    realtime_scheduling: ''
    run: 'True'
    run_command: '{python} -u {filename}'
    run_options: run
    sizing_mode: fixed
    thread_safe_setters: ''
    title: Not titled yet
    window_size: (1000,1000)
  states:
    bus_sink: false
    bus_source: false
    bus_structure: null
    coordinate: [8, 8]
    rotation: 0
    state: enabled

blocks:
- name: blocks_null_source_0
  id: blocks_null_source
  parameters:
    affinity: ''
    alias: ''
    bus_structure_source: '[[0,],]'
    comment: ''
    maxoutbuf: '0'
    minoutbuf: '0'
    num_outputs: '1'
    type: complex
    vlen: '1'
  states:
    bus_sink: false
    bus_source: false
    bus_structure: null
    coordinate: [352, 40.0]
    rotation: 0
    state: enabled
- name: blocks_throttle2_0
  id: blocks_throttle2
  parameters:
    affinity: ''
    alias: ''
    comment: ''
    ignoretag: 'True'
    limit: items
    maximum: '1'
    maxoutbuf: '0'
    minoutbuf: '0'
    samples_per_second: 1e-6
    type: complex
    vlen: '1'
  states:
    bus_sink: false
    bus_source: false
    bus_structure: null
    coordinate: [496, 20.0]
    rotation: 0
    state: enabled
- name: network_tcp_sink_0
  id: network_tcp_sink
  parameters:
    addr: 127.0.0.1
    affinity: ''
    alias: ''
    comment: ''
    mode: '2'
    port: port
    type: complex
    vlen: '1'
  states:
    bus_sink: false
    bus_source: false
    bus_structure: null
    coordinate: [656, 28.0]
    rotation: 0
    state: enabled
- name: port
  id: parameter
  parameters:
    alias: ''
    comment: ''
    hide: none
    label: port
    short_id: p
    type: intx
    value: '9999'
  states:
    bus_sink: false
    bus_source: false
    bus_structure: null
    coordinate: [208, 12.0]
    rotation: 0
    state: enabled

connections:
- [blocks_null_source_0, '0', blocks_throttle2_0, '0']
- [blocks_throttle2_0, '0', network_tcp_sink_0, '0']

metadata:
  file_format: 1
  grc_version: v3.11.0.0git-655-g7d61746e

repro6698.svg