ShawnHuang/Linux project II.md

## Linux project II.md

      
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              Linux project II.md
            
          
Score:
115 points.


Description:


Write a CPU-bound program cpu_bound.c as follows:
       #include <stdio.h>
       main()
       {
          int  a;

          while(1)
            ++a;
       }


Write an I/O-bound program io_bound.c as follows:
       #include <stdio.h>
       main()
       {
         FILE  *out;
         char  c;
         int   a;

         while(1)
         {
           for(a=0;a>0;)
             ++a;

          if((out=fopen("io_bound.data","w"))!=NULL)
          {
            c=38;
            for(a=0; a<10000;a++)
            {
              putc(c,out);
              if(++c>126)
                c=38;
            }
            fclose(out);
          }
          else
          {
            printf("Cannot open file.\n");
            exit(0);
          }
         }
       }


Execute the above two programs in background.


Change the kernel so that you can utilize a new system call to learn

How many process switches does the above CPU-bound process make during 3 minutes' execution?
How many process switches does the above I/O-bound process make during 3 minutes' execution?
How long is the CPU bound process idle during the 3 minutes' execution.
How long is the I/O bound process idle during the 3 minutes' execution.


Write a program test_process_switch.c as follows to test your new kernel. The program accepts two parameters. The first parameter is the PID of the above CPU-bound process. The second parameter is the PID of the above I/O bound process.
        #include <stdio.h>
        #include <unistd.h>
        #include <stdlib.h>

        struct process_switch_info
        {
          unsigned int   counter_cpu, counter_IO;
          struct timeval time_cpu, time_IO;
        };


        main(int argc, char **argv)
        {
          int                        pid_cpu,pid_IO;
          unsigned long              temp_ul;
          struct process_switch_info ps_info;

          
          if(argc<3)
          {
            printf("Input the PIDs of the CPU-bound process and I/O-bound process as the parameters of this executable.\n");
            printf("Format: program pid_cpu pid_IO\n");
            exit(0);
          }

          pid_cpu=atoi(argv[1]);
          pid_IO=atoi(argv[2]);

          get_process_switch_info(&ps_info,pid_cpu,pid_IO);    //new system call
          /*===========================================================================*/
          /*     prototype of the new system call is as follows                        */
          /*     void get_process_switch_info(struct process_switch_info *, int, int)  */
          /*===========================================================================*/
          temp_ul=(ps_info.time_cpu.tv_sec * 1000000 + ps_info.time_cpu.tv_usec);
          printf("The CPU-bound process has made %ld process switches\n", ps_info.counter_cpu);
          printf("This process has idle %ul usecs\n", temp_ul); 

          temp_ul=(ps_info.time_IO.tv_sec * 1000000 + ps_info.time_IO.tv_usec);
          printf("The IO-bound process has made %ld process switches\n", ps_info.counter_IO);
          printf("This process has idle %ul usecs\n", temp_ul); 
        }


Hint:

You may need to add some fields in the END of the struct task_struct to record related info. The initial values of these fields are 0;
You can add some code at function copy_process() or copy_thread() to set the initial values of the above four fields as 0.
Each time when the schedule() makes a process switch from process 1 to process 2, you need to add the number of process switches of process 2 by 1.
Each time when schedule() makes a process switch from process 1 to process 2, process 1 begins idle until next time schedule() makes a process switch to give CPU control to process 1 again. During the exectuiont of a process, the process may experience process switch several times. Hence the total idle time of a process is the sum of all the above individual idle time.
Inside the kernel, you could call do_gettimeofday() to get a microsecond-resolution timestamp, or getnstimeofday() for nanosecond resolution.
You may need to add a new system call to do project 2.


Check the "Referenced Material" part of the Course web site to see how to add a new system call in Linux.


Project Submission:

The due day of reports submission is 17th Jan. 2015
The demo will be held on 19th Jan. 2015, 20th Jan. 2015, and 21st Jan. 2015
Contact the TAs to choose your demo time before 16thd Jan. 2015
On site demo of this project is required.
When demonstrating your projects, the TAs will ask you some questions regarding to your projects. Part of your project grade is determined by your answers to the questions.
You need to submit both an electronic version and a hard-copy of your project report to the TAs.

The electronic versions could be sent to the TAs through e-mails.
Do not forget writing the names and student IDs of all members in your team.
Your report should contain:

Your source code
the execution results


Late submission