Time system call help xv6. 1. If command is “time l<PID>”, it should display in

Question

Time system call help xv6.

1. If command is “time l<PID>”, it should display in number of ticks
2. If command is “time <PID> -s”, it should display time in seconds (floating point value).

The code below can time the number inticks, im just struggling to do the check for the "-s" part if the user chooses to input that.

time.c

#include "types.h"
#include "user.h"
#include "date.h"

int
main (int argc, char *argv[])
{
    int startTicks = uptime();

    int pid = fork();
    if (pid < 0) {
        printf(2, "Error: Invalid PID! ");
        exit();
    }
    if (pid > 0)
        wait();
    if (pid == 0) {
        if (exec(argv[1], argv + 1) < 0) {
            printf(2, "Error: Exec fails! ");
            exit();
        }
    }

    int endTicks = uptime();

    int seconds = (endTicks - startTicks);
    printf(1, " Real Time in ticks: %d tick(s) ", seconds);
    exit();
}

Explanation / Answer

Here as per your requirement you need to display time in seconds (floating point value).

We also need to caluclate the milliseconds in our code. We know that 1 second has 100 miliseconds. Using this condition I will share the code changes.

As, it is a floating point value, you need to make follwing changes to your existing code for "time <PID> -s” command :

Please replace this part of your code with the code I am sharing :

int seconds = (endTicks - startTicks);
printf(1, " Real Time in ticks: %d tick(s) ", seconds);

Please add below code in place of the above 2 lines in your code :

int seconds = (endTicks - startTicks)/100;
int remainderSeconds = (endTicks - startTicks)%100;

printf(1, "%s", argv[1]);
printf(1, " Time in ticks: %d tick(s) ", seconds);
if (remainderSeconds < 10){
printf(1, "0");
}
printf(1, "%d ", remainderSeconds);

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