This script demonstrates the adjustment of thread priorities

thread_priority_hack.py

import threading
import os
import signal
import time


"""
This script demonstrates the adjustment of thread priorities and handling Ctrl+C to gracefully stop threads.

Thread Priority Mechanism:
- The `thread_priority_test` function creates multiple threads with different niceness values.
- It uses the `os.nice()` function to set thread niceness, which is similar to thread priority.
- If the niceness is set to 0 (default), it attempts to set thread priority explicitly on Linux systems using the `setpriority` function.
- Each thread runs a loop until a termination signal is received (e.g., Ctrl+C).
- During the loop, it continuously updates its niceness value and maintains a dictionary of statistics.

Ctrl+C Signal Handling:
- The `signal_handler` function is set up to handle Ctrl+C signals.
- When Ctrl+C is detected, it sets the `kill_event`, signaling all threads to stop gracefully.

Usage:
- Threads are created with different niceness values (0, -2, -4).
- The script uses the `threading` module to manage threads.
- To stop the threads, press Ctrl+C, which triggers the signal handler and stops all threads.
- The statistics of thread niceness and counts are stored in the `cntr_stats_dict`.

Note:
- Thread priorities might not work on all systems, and explicit priority settings are typically limited to Unix/Linux.
- The script provides a basic demonstration of priority adjustment and signal handling.


Sample output with diff niceness:
{19: 206808916, 15: 215252820, 10: 219746028, 5: 226310260, 0: 231552779, -5: 242480906, -10: 249047980, -15: 254036155, -20: 253950489}
Niceness -20 (highest priority) enjoyed max count as it might have got more os time.
"""

# Set up a signal handler for Ctrl+C
def signal_handler(sig, frame):
    print("Ctrl+C detected. Stopping threads...")
    kill_event.set()


def thread_priority_test(tag, niceness):
    print(f'[*]Starting {tag} thread....')
    ix = 0
    os.nice(niceness)
    # if niceness == 0:
    #     setpriority(tag, linux_nice=20)

    while not kill_event.is_set():
        niceness = os.nice(0)
        ix += 1
        cntr_stats_dict[niceness] = ix


kill_event = threading.Event()
nvalues = range(0, -5, -2)
cntr_stats_dict = dict()

threads = [threading.Thread(target=thread_priority_test, args=(f'Test_{nvalue}', nvalue)) for nvalue in nvalues]

signal.signal(signal.SIGINT, signal_handler)

for thread in threads:
    thread.start()

while not kill_event.is_set():
    time.sleep(3)
    print(cntr_stats_dict)

This script demonstrates the adjustment of thread priorities using os.nice()

Thread Priority Mechanism:

• The thread_priority_test function creates multiple threads with different niceness values.
• It uses the os.nice() function to set thread niceness, which is similar to thread priority.
• Each thread runs a loop until a termination signal is received (e.g., Ctrl+C).
• During the loop, it runs a counter and maintains a dictionary of statistics.

Ctrl+C Signal Handling:

• The signal_handler function is set up to handle Ctrl+C signals.
• When Ctrl+C is detected, it sets the kill_event, signaling all threads to stop gracefully.

Usage:

• Threads are created with different niceness values (0, -2, -4).
• The script uses the threading module to manage threads.
• To stop the threads, press Ctrl+C, which triggers the signal handler and stops all threads.
• The statistics of thread niceness and counts are stored in the cntr_stats_dict.

Note:

• Thread priorities might not work on all systems, and explicit priority settings are typically limited to Unix/Linux.
• The script provides a basic demonstration of priority adjustment and signal handling.

Sample output with diff niceness:
.
.
.
{19: 30465492, 15: 32170064, 10: 32333765, 5: 33807670, 0: 34757313, -5: 35629011, -10: 36933416, -15: 37232012, -20: 38131850}
{19: 30629167, 15: 32293583, 10: 32511094, 5: 33979049, 0: 34933933, -5: 35851529, -10: 37110963, -15: 37382310, -20: 38321260}
{19: 30757137, 15: 32382210, 10: 32615585, 5: 34209006, 0: 35110487, -5: 36092311, -10: 37275568, -15: 37575795, -20: 38537091}
{19: 30924631, 15: 32529657, 10: 32810417, 5: 34379821, 0: 35350722, -5: 36272427, -10: 37426454, -15: 37817350, -20: 38724243}
.
.
.

{19: 205842802, 15: 214267971, 10: 218849437, 5: 225239074, 0: 230610955, -5: 241416151, -10: 247995994, -15: 253017885, -20: 252717624}
{19: 205977182, 15: 214406245, 10: 218945774, 5: 225340416, 0: 230725614, -5: 241551976, -10: 248129734, -15: 253131631, -20: 252900676}
{19: 206104915, 15: 214537418, 10: 219056155, 5: 225481394, 0: 230844420, -5: 241665192, -10: 248241036, -15: 253251922, -20: 253072552}
{19: 206262874, 15: 214702527, 10: 219151508, 5: 225571215, 0: 230989691, -5: 241776664, -10: 248389458, -15: 253365640, -20: 253217771}