Lottery Scheduling Simulator

References

• Lottery Scheduling - Wikipedia
• OSTEP - Lottery Scheduling

Usage

Basic Mode

./lottery_sched <seed> <loops>

Parameters:

• <seed>: Seed for the random number generator
• <loops>: Number of lottery iterations

Example:

./lottery_sched 42 10000

Demo Mode (with ticket mechanisms)

./lottery_sched <seed> <loops> --demo

This mode executes transfer, inflation, and deflation operations on tickets before running the simulation, demonstrating how these mechanisms work.

Example:

./lottery_sched 42 5000 --demo

Results Interpretation

Typical output:

PID   Name        Tickets  Wins    Actual%   Expected%   Deviation
----  --------    -------  ----    -------   ---------   ---------
1     WebServer   100      1539    15.39%    15.38%      +0.01%
2     Database    200      3147    31.47%    30.77%      +0.70%
3     Cache       300      4583    45.83%    46.15%      -0.32%
4     Worker      50       731     7.31%     7.69%       -0.38%

Standard Deviation: 0.43%

Explanation:

• Tickets: Current number of tickets for the process
• Wins: Number of times the process won the lottery
• Actual%: Actual percentage of wins
• Expected%: Theoretical percentage based on tickets
• Deviation: Difference between actual and expected
• Standard Deviation: How consistent the distribution is

A low deviation (< 1%) indicates that the algorithm is working correctly.

Available Functions

Function	Description
insert(pid, name, tickets)	Create a new process
remove_process(pid)	Remove a process
find_process(pid)	Find a process by ID
transfer_tickets(from_pid, to_pid, amount)	Transfer tickets between processes
inflate_tickets(pid, amount)	Increase a process's tickets
deflate_tickets(pid, amount)	Decrease a process's tickets
print_list()	Display process list
print_stats(loops)	Display simulation statistics