trunk/tests/kernel/test-nop-speed.c

   1 /* test-nop-speed.c
   2  *
   3  */
   4
   5 #include <linux/module.h>
   6 #include <linux/proc_fs.h>
   7 #include <linux/sched.h>
   8 #include <linux/timex.h>
   9 #include <linux/marker.h>
  10 #include <asm/ptrace.h>
  11
  12 #define NR_TESTS 10000000
  13
  14 int var, var2;
  15
  16 struct proc_dir_entry *pentry = NULL;
  17
  18 void empty(void)
  19 {
  20         asm volatile ("");
  21         var += 50;
  22         var /= 10;
  23         var *= var2;
  24 }
  25
  26 void twobytesjump(void)
  27 {
  28         asm volatile ("jmp 1f\n\t"
  29                 ".byte 0x00, 0x00, 0x00\n\t"
  30                 "1:\n\t");
  31         var += 50;
  32         var /= 10;
  33         var *= var2;
  34 }
  35
  36 void fivebytesjump(void)
  37 {
  38         asm (".byte 0xe9, 0x00, 0x00, 0x00, 0x00\n\t");
  39         var += 50;
  40         var /= 10;
  41         var *= var2;
  42 }
  43
  44 void threetwonops(void)
  45 {
  46         asm (".byte 0x66,0x66,0x90,0x66,0x90\n\t");
  47         var += 50;
  48         var /= 10;
  49         var *= var2;
  50 }
  51
  52 void fivebytesnop(void)
  53 {
  54         asm (".byte 0x66,0x66,0x66,0x66,0x90\n\t");
  55         var += 50;
  56         var /= 10;
  57         var *= var2;
  58 }
  59
  60 void fivebytespsixnop(void)
  61 {
  62         asm (".byte 0x0f,0x1f,0x44,0x00,0\n\t");
  63         var += 50;
  64         var /= 10;
  65         var *= var2;
  66 }
  67
  68 void perform_test(const char *name, void (*callback)(void))
  69 {
  70         unsigned int i;
  71         cycles_t cycles1, cycles2;
  72         unsigned long flags;
  73
  74         local_irq_save(flags);
  75         rdtsc_barrier();
  76         cycles1 = get_cycles();
  77         rdtsc_barrier();
  78         for(i=0; i<NR_TESTS; i++) {
  79                 callback();
  80         }
  81         rdtsc_barrier();
  82         cycles2 = get_cycles();
  83         rdtsc_barrier();
  84         local_irq_restore(flags);
  85         printk("test %s cycles : %llu\n", name, cycles2-cycles1);
  86 }
  87
  88 static int my_open(struct inode *inode, struct file *file)
  89 {
  90         printk("NR_TESTS %d\n", NR_TESTS);
  91
  92         perform_test("empty", empty);
  93         perform_test("2-bytes jump", twobytesjump);
  94         perform_test("5-bytes jump", fivebytesjump);
  95         perform_test("3/2 nops", threetwonops);
  96         perform_test("5-bytes nop with long prefix", fivebytesnop);
  97         perform_test("5-bytes P6 nop", fivebytespsixnop);
  98
  99         return -EPERM;
 100 }
 101
 102
 103 static struct file_operations my_operations = {
 104         .open = my_open,
 105 };
 106
 107 int init_module(void)
 108 {
 109         pentry = create_proc_entry("testnops", 0444, NULL);
 110         if (pentry)
 111                 pentry->proc_fops = &my_operations;
 112
 113         return 0;
 114 }
 115
 116 void cleanup_module(void)
 117 {
 118         remove_proc_entry("testnops", NULL);
 119 }
 120
 121 MODULE_LICENSE("GPL");
 122 MODULE_AUTHOR("Mathieu Desnoyers");
 123 MODULE_DESCRIPTION("NOP Test");