/******************************************************************************/
/*                                                                            */
/* Copyright (c) International Business Machines  Corp., 2007                 */
/*                                                                            */
/* This program is free software;  you can redistribute it and/or modify      */
/* it under the terms of the GNU General Public License as published by       */
/* the Free Software Foundation; either version 2 of the License, or          */
/* (at your option) any later version.                                        */
/*                                                                            */
/* This program is distributed in the hope that it will be useful,            */
/* but WITHOUT ANY WARRANTY;  without even the implied warranty of            */
/* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See                  */
/* the GNU General Public License for more details.                           */
/*                                                                            */
/* You should have received a copy of the GNU General Public License          */
/* along with this program;  if not, write to the Free Software               */
/* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA    */
/*                                                                            */
/******************************************************************************/

/******************************************************************************/
/*                                                                            */
/* File:        cpuctl_test02.c                                               */
/*                                                                            */
/* Description: This is a c program that tests the cpucontroller fairness of  */
/*              scheduling the tasks according to their group shares. This    */
/*              testcase tests the ability of the cpu controller to provide   */
/*              fairness for share values (absolute).                         */
/*                                                                            */
/* Total Tests: 2                                                             */
/*                                                                            */
/* Test 04:     Nice value effect on group scheduling                         */
/* Test 05:     Task migration test                                           */
/*                                                                            */
/* Test Name:   cpu_controller_test02                                         */
/*                                                                            */
/* Test Assertion                                                             */
/*              Please refer to the file cpuctl_testplan.txt                  */
/*                                                                            */
/* Author:      Sudhir Kumar skumar@linux.vnet.ibm.com                        */
/*                                                                            */
/* History:                                                                   */
/* Created-     20/12/2007 -Sudhir Kumar <skumar@linux.vnet.ibm.com>          */
/*                                                                            */
/******************************************************************************/

#include <unistd.h>
#include <math.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/resource.h>
#include <sys/syscall.h>
#include <sys/time.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <time.h>
#include <unistd.h>

#include "../libcontrollers/libcontrollers.h"
#include "test.h"		/* LTP harness APIs */

#define TIME_INTERVAL	30	/* Time interval in seconds */
#define NUM_INTERVALS	3	/* How many iterations of TIME_INTERVAL */

char *TCID = "cpuctl_test02";
int TST_TOTAL = 1;
pid_t scriptpid;
char path[] = "/dev/cpuctl";

extern void cleanup()
{
	kill(scriptpid, SIGUSR1);	/* Inform the shell to do cleanup */
	tst_exit();		/* Report exit status */
}

int migrate_task();
volatile int timer_expired = 0;

int main(int argc, char *argv[])
{

	int test_num;
	int task_num;
	int len;
	int num_cpus;		/* Total time = TIME_INTERVAL *num_cpus in the machine */
	int migrate = 0;	/* For task migration */
	char mygroup[FILENAME_MAX], mytaskfile[FILENAME_MAX];
	char mysharesfile[FILENAME_MAX], ch;
	/* Following variables are to capture parameters from script */
	char *group_num_p, *mygroup_p, *script_pid_p, *num_cpus_p, *test_num_p,
	    *task_num_p;
	pid_t pid;
	gid_t mygroup_num;	/* A number attached with a group */
	int fd;			/* A descriptor to open a fifo for synchronized start */
	int counter = 0;	/* To take n number of readings */
	double total_cpu_time,	/* Accumulated cpu time */
	 delta_cpu_time,	/* Time the task could run on cpu(s) (in an interval) */
	 prev_cpu_time = 0;
	double exp_cpu_time;	/* Expected time in % as obtained by shares calculation */

	struct rusage cpu_usage;
	time_t current_time, prev_time, delta_time;
	unsigned int fmyshares, num_tasks;	/* f-> from file. num_tasks is tasks in this group */
	struct sigaction newaction, oldaction;

	mygroup_num = -1;
	num_cpus = 0;
	task_num = 0;
	test_num = 0;

	/* Signal handling for alarm */
	sigemptyset(&newaction.sa_mask);
	newaction.sa_handler = signal_handler_alarm;
	newaction.sa_flags = 0;
	sigaction(SIGALRM, &newaction, &oldaction);

	/* Collect the parameters passed by the script */
	group_num_p = getenv("GROUP_NUM");
	mygroup_p = getenv("MYGROUP");
	script_pid_p = getenv("SCRIPT_PID");
	num_cpus_p = getenv("NUM_CPUS");
	test_num_p = getenv("TEST_NUM");
	task_num_p = getenv("TASK_NUM");
	/* Check if all of them are valid */
	if ((test_num_p != NULL)
	    && (((test_num = atoi(test_num_p)) == 4)
		|| ((test_num = atoi(test_num_p)) == 5))) {
		if ((group_num_p != NULL) && (mygroup_p != NULL)
		    && (script_pid_p != NULL) && (num_cpus_p != NULL)
		    && (task_num_p != NULL)) {
			mygroup_num = atoi(group_num_p);
			scriptpid = atoi(script_pid_p);
			num_cpus = atoi(num_cpus_p);
			task_num = atoi(task_num_p);
			sprintf(mygroup, "%s", mygroup_p);
		} else {
			tst_brkm(TBROK, cleanup,
				 "Invalid other input parameters\n");
		}
	} else {
		tst_brkm(TBROK, cleanup, "Invalid test number passed\n");
	}

	sprintf(mytaskfile, "%s", mygroup);
	sprintf(mysharesfile, "%s", mygroup);
	strcat(mytaskfile, "/tasks");
	strcat(mysharesfile, "/cpu.shares");
	pid = getpid();
	write_to_file(mytaskfile, "a", pid);	/* Assign the task to it's group */

	fd = open("./myfifo", 0);
	if (fd == -1) {
		tst_brkm(TBROK, cleanup,
			 "Could not open fifo for synchronization");
	}

	read(fd, &ch, 1);	/* To block all tasks here and fire them up at the same time */

	/*
	 * We now calculate the expected % cpu time of this task by getting
	 * it's group's shares, the total shares of all the groups and the
	 * number of tasks in this group.
	 */
	FLAG = 0;
	total_shares = 0;
	shares_pointer = &total_shares;
	len = strlen(path);
	if (!strncpy(fullpath, path, len))
		tst_brkm(TBROK, cleanup, "Could not copy directory path %s ",
			 path);

	if (scan_shares_files(shares_pointer) != 0)
		tst_brkm(TBROK, cleanup,
			 "From function scan_shares_files in %s ", fullpath);

	/* return val: -1 in case of function error, else 2 is min share value */
	if ((fmyshares = read_shares_file(mysharesfile)) < 2)
		tst_brkm(TBROK, cleanup, "in reading shares files  %s ",
			 mysharesfile);

	if ((read_file(mytaskfile, GET_TASKS, &num_tasks)) < 0)
		tst_brkm(TBROK, cleanup, "in reading tasks files  %s ",
			 mytaskfile);

	exp_cpu_time = (double)(fmyshares * 100) / (total_shares * num_tasks);

	prev_time = time(NULL);	/* Note down the time */

	while (1) {
		/* Need to run some cpu intensive task, which also frequently checks the timer value */
		double f = 274.345, mytime;	/*just a float number to take sqrt */
		alarm(TIME_INTERVAL);
		timer_expired = 0;
		while (!timer_expired)	/* Let the task run on cpu for TIME_INTERVAL */
			f = sqrt(f * f);	/* Time of this operation should not be high otherwise we can
						 * exceed the TIME_INTERVAL to measure cpu usage
						 */
		current_time = time(NULL);
		delta_time = current_time - prev_time;	/* Duration in case its not exact TIME_INTERVAL */

		getrusage(0, &cpu_usage);
		total_cpu_time = (cpu_usage.ru_utime.tv_sec + cpu_usage.ru_utime.tv_usec * 1e-6 +	/* user time */
				  cpu_usage.ru_stime.tv_sec + cpu_usage.ru_stime.tv_usec * 1e-6);	/* system time */
		delta_cpu_time = total_cpu_time - prev_cpu_time;

		prev_cpu_time = total_cpu_time;
		prev_time = current_time;

		/* calculate % cpu time each task gets */
		if (delta_time > TIME_INTERVAL)
			mytime =
			    (delta_cpu_time * 100) / (delta_time * num_cpus);
		else
			mytime =
			    (delta_cpu_time * 100) / (TIME_INTERVAL * num_cpus);

		fprintf(stdout, "Grp:-%3d task-%3d:CPU TIME{calc:-%6.2f(s)i.e. %6.2f(%%)exp:-%6.2f(%%)}\
with %u(shares) in %lu (s) INTERVAL\n", mygroup_num, task_num, delta_cpu_time,
			mytime, exp_cpu_time, fmyshares, delta_time);

		counter++;

		if (counter >= NUM_INTERVALS) {	/* Take n sets of readings for each shares value */
			switch (test_num) {
			case 4:	/* Test04 */
				exit(0);	/* This task is done with its job */
				break;
			case 5:	/* Test 05 */
				if (migrate == 0) {
					counter = 0;
					fprintf(stdout,
						"FIRST RUN COMPLETED FOR TASK %d\n",
						task_num);
					migrate = 1;
				} else {
					fprintf(stdout,
						"SECOND RUN COMPLETED FOR TASK %d\n",
						task_num);
					exit(0);
				}
				break;
			default:
				tst_brkm(TBROK, cleanup,
					 "Invalid test number passed\n");
				break;

			}	/* end switch */
		}
		if ((migrate == 1) && (counter == 0)) {
			if (task_num == 1) {
				if (migrate_task() != 0)
					tst_brkm(TFAIL, cleanup,
						 "Could not migrate task 1 ");
				else
					fprintf(stdout,
						"TASK 1 MIGRATED FROM GROUP 1 TO GROUP 2\n");
				strcpy(mytaskfile, "/dev/cpuctl/group_2/tasks");
			}
			/*
			 * Read the shares files and again calculate the cpu fraction
			 * In test 2(case 4) we need to read tasks file as we migrate task
			 * Q?? How to ensure other tasks do not read before task 1 migration
			 */
			if ((read_file(mytaskfile, GET_TASKS, &num_tasks)) < 0)
				tst_brkm(TBROK, cleanup,
					 "in reading tasks files  %s ",
					 mytaskfile);
			exp_cpu_time =
			    (double)(fmyshares * 100) / (total_shares *
							 num_tasks);
		}
	}			/* end while */
}				/* end main */

int migrate_task()
{
	char target[32] = "/dev/cpuctl/group_2/tasks";	/* Hard coding..Will try dynamic */
	pid_t pid = getpid();
	return (write_to_file(target, "a", pid));
}
