1 // SPDX-License-Identifier: GPL-2.0 2 #include <linux/init.h> 3 #include <linux/kthread.h> 4 #include <linux/hrtimer.h> 5 #include <linux/fs.h> 6 #include <linux/debugfs.h> 7 #include <linux/export.h> 8 #include <linux/spinlock.h> 9 #include <asm/debug.h> 10 11 static int ss_get(void *data, u64 *val) 12 { 13 ktime_t start, finish; 14 int loops; 15 int cont; 16 DEFINE_RAW_SPINLOCK(ss_spin); 17 18 loops = 1000000; 19 cont = 1; 20 21 start = ktime_get(); 22 23 while (cont) { 24 raw_spin_lock(&ss_spin); 25 loops--; 26 if (loops == 0) 27 cont = 0; 28 raw_spin_unlock(&ss_spin); 29 } 30 31 finish = ktime_get(); 32 33 *val = ktime_us_delta(finish, start); 34 35 return 0; 36 } 37 38 DEFINE_SIMPLE_ATTRIBUTE(fops_ss, ss_get, NULL, "%llu\n"); 39 40 41 42 struct spin_multi_state { 43 raw_spinlock_t lock; 44 atomic_t start_wait; 45 atomic_t enter_wait; 46 atomic_t exit_wait; 47 int loops; 48 }; 49 50 struct spin_multi_per_thread { 51 struct spin_multi_state *state; 52 ktime_t start; 53 }; 54 55 static int multi_other(void *data) 56 { 57 int loops; 58 int cont; 59 struct spin_multi_per_thread *pt = data; 60 struct spin_multi_state *s = pt->state; 61 62 loops = s->loops; 63 cont = 1; 64 65 atomic_dec(&s->enter_wait); 66 67 while (atomic_read(&s->enter_wait)) 68 ; /* spin */ 69 70 pt->start = ktime_get(); 71 72 atomic_dec(&s->start_wait); 73 74 while (atomic_read(&s->start_wait)) 75 ; /* spin */ 76 77 while (cont) { 78 raw_spin_lock(&s->lock); 79 loops--; 80 if (loops == 0) 81 cont = 0; 82 raw_spin_unlock(&s->lock); 83 } 84 85 atomic_dec(&s->exit_wait); 86 while (atomic_read(&s->exit_wait)) 87 ; /* spin */ 88 return 0; 89 } 90 91 static int multi_get(void *data, u64 *val) 92 { 93 ktime_t finish; 94 struct spin_multi_state ms; 95 struct spin_multi_per_thread t1, t2; 96 97 ms.lock = __RAW_SPIN_LOCK_UNLOCKED("multi_get"); 98 ms.loops = 1000000; 99 100 atomic_set(&ms.start_wait, 2); 101 atomic_set(&ms.enter_wait, 2); 102 atomic_set(&ms.exit_wait, 2); 103 t1.state = &ms; 104 t2.state = &ms; 105 106 kthread_run(multi_other, &t2, "multi_get"); 107 108 multi_other(&t1); 109 110 finish = ktime_get(); 111 112 *val = ktime_us_delta(finish, t1.start); 113 114 return 0; 115 } 116 117 DEFINE_SIMPLE_ATTRIBUTE(fops_multi, multi_get, NULL, "%llu\n"); 118 119 static int __init spinlock_test(void) 120 { 121 debugfs_create_file("spin_single", S_IRUGO, mips_debugfs_dir, NULL, 122 &fops_ss); 123 debugfs_create_file("spin_multi", S_IRUGO, mips_debugfs_dir, NULL, 124 &fops_multi); 125 return 0; 126 } 127 device_initcall(spinlock_test); 128