Command Processor Scheduler

Usage

Execute shell commands in parallel.

mpirun -np num_procs ./cps tasklist

Example

To compile and execute with 4 processes:

make
mpirun -np 4 ./cps task.sh

The list of shell commands should be provided in a file, as shown below:

$ cat task.sh
# tasks
sleep 1.1
sleep 1.4
sleep 0.9
sleep 1.1
sleep 1.3
sleep 1.2

Lines beginning with # are treated as comments and are ignored during execution.

Output

After execution, a log file named cps.log will be generated:

$ cat cps.log
Number of tasks : 6
Number of processes : 4
Total execution time: 7.043 [s]
Elapsed time: 2.613 [s]
Parallel Efficiency : 0.898456

Task list:
Command : Elapsed time
sleep 1.1 : 1.11 [s]
sleep 1.4 : 1.408 [s]
sleep 0.9 : 0.907 [s]
sleep 1.1 : 1.106 [s]
sleep 1.3 : 1.308 [s]
sleep 1.2 : 1.204 [s]

Parallel Execution Details

One process is reserved for scheduling, so the number of processes available for executing tasks is num_procs - 1.

In the example above:

• The total execution time is 7.043 seconds.
• The elapsed time (wall time) is 2.613 seconds.
• The effective number of worker processes is 4 - 1 = 3.

Therefore, the parallel efficiency is calculated as:

7.043 / (2.613 * 3) = 0.898456 ≈ 89.8%

License

This software is released under the MIT License, see LICENSE.