[SOLVED] CS代考计算机代写 /* Measures the correctness of the “nice” implementation.

/* Measures the correctness of the “nice” implementation.

The “fair” tests run either 2 or 20 threads all niced to 0.
The threads should all receive approximately the same number
of ticks.Each test runs for 30 seconds, so the ticks should
also sum to approximately 30 * 100 == 3000 ticks.

The mlfqs-nice-2 test runs 2 threads, one with nice 0, the
other with nice 5, which should receive 1,904 and 1,096 ticks,
respectively, over 30 seconds.

The mlfqs-nice-10 test runs 10 threads with nice 0 through 9.
They should receive 672, 588, 492, 408, 316, 232, 152, 92, 40,
and 8 ticks, respectively, over 30 seconds.

(The above are computed via simulation in mlfqs.pm.) */

#include
#include
#include “tests/threads/tests.h”
#include “threads/init.h”
#include “threads/malloc.h”
#include “threads/palloc.h”
#include “threads/synch.h”
#include “threads/thread.h”
#include “devices/timer.h”

static void test_mlfqs_fair (int thread_cnt, int nice_min, int nice_step);

void
test_mlfqs_fair_2 (void)
{
test_mlfqs_fair (2, 0, 0);
}

void
test_mlfqs_fair_20 (void)
{
test_mlfqs_fair (20, 0, 0);
}

void
test_mlfqs_nice_2 (void)
{
test_mlfqs_fair (2, 0, 5);
}

void
test_mlfqs_nice_10 (void)
{
test_mlfqs_fair (10, 0, 1);
}
�
#define MAX_THREAD_CNT 20

struct thread_info
{
int64_t start_time;
int tick_count;
int nice;
};

static void load_thread (void *aux);

static void
test_mlfqs_fair (int thread_cnt, int nice_min, int nice_step)
{
struct thread_info info[MAX_THREAD_CNT];
int64_t start_time;
int nice;
int i;

ASSERT (thread_mlfqs);
ASSERT (thread_cnt <= MAX_THREAD_CNT);ASSERT (nice_min >= -10);
ASSERT (nice_step >= 0);
ASSERT (nice_min + nice_step * (thread_cnt – 1) <= 20);thread_set_nice (-20);start_time = timer_ticks ();msg (“Starting %d threads…”, thread_cnt);nice = nice_min;for (i = 0; i < thread_cnt; i++) {struct thread_info *ti = &info[i];char name[16];ti->start_time = start_time;
ti->tick_count = 0;
ti->nice = nice;

snprintf(name, sizeof name, “load %d”, i);
thread_create (name, PRI_DEFAULT, load_thread, ti);

nice += nice_step;
}
msg (“Starting threads took %”PRId64″ ticks.”, timer_elapsed (start_time));

msg (“Sleeping 40 seconds to let threads run, please wait…”);
timer_sleep (40 * TIMER_FREQ);

for (i = 0; i < thread_cnt; i++)msg (“Thread %d received %d ticks.”, i, info[i].tick_count);}static voidload_thread (void *ti_) {struct thread_info *ti = ti_;int64_t sleep_time = 5 * TIMER_FREQ;int64_t spin_time = sleep_time + 30 * TIMER_FREQ;int64_t last_time = 0;thread_set_nice (ti->nice);
timer_sleep (sleep_time – timer_elapsed (ti->start_time));
while (timer_elapsed (ti->start_time) < spin_time) {int64_t cur_time = timer_ticks ();if (cur_time != last_time)ti->tick_count++;
last_time = cur_time;
}
}