1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * Copyright (C) 2020 HiSilicon Limited. 4 */ 5 6 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 7 8 #include <linux/debugfs.h> 9 #include <linux/delay.h> 10 #include <linux/device.h> 11 #include <linux/dma-mapping.h> 12 #include <linux/kernel.h> 13 #include <linux/kthread.h> 14 #include <linux/map_benchmark.h> 15 #include <linux/math64.h> 16 #include <linux/module.h> 17 #include <linux/pci.h> 18 #include <linux/platform_device.h> 19 #include <linux/slab.h> 20 #include <linux/timekeeping.h> 21 22 struct map_benchmark_data { 23 struct map_benchmark bparam; 24 struct device *dev; 25 struct dentry *debugfs; 26 enum dma_data_direction dir; 27 atomic64_t sum_map_100ns; 28 atomic64_t sum_unmap_100ns; 29 atomic64_t sum_sq_map; 30 atomic64_t sum_sq_unmap; 31 atomic64_t loops; 32 }; 33 34 static int map_benchmark_thread(void *data) 35 { 36 void *buf; 37 dma_addr_t dma_addr; 38 struct map_benchmark_data *map = data; 39 int npages = map->bparam.granule; 40 u64 size = npages * PAGE_SIZE; 41 int ret = 0; 42 43 buf = alloc_pages_exact(size, GFP_KERNEL); 44 if (!buf) 45 return -ENOMEM; 46 47 while (!kthread_should_stop()) { 48 u64 map_100ns, unmap_100ns, map_sq, unmap_sq; 49 ktime_t map_stime, map_etime, unmap_stime, unmap_etime; 50 ktime_t map_delta, unmap_delta; 51 52 /* 53 * for a non-coherent device, if we don't stain them in the 54 * cache, this will give an underestimate of the real-world 55 * overhead of BIDIRECTIONAL or TO_DEVICE mappings; 56 * 66 means evertything goes well! 66 is lucky. 57 */ 58 if (map->dir != DMA_FROM_DEVICE) 59 memset(buf, 0x66, size); 60 61 map_stime = ktime_get(); 62 dma_addr = dma_map_single(map->dev, buf, size, map->dir); 63 if (unlikely(dma_mapping_error(map->dev, dma_addr))) { 64 pr_err("dma_map_single failed on %s\n", 65 dev_name(map->dev)); 66 ret = -ENOMEM; 67 goto out; 68 } 69 map_etime = ktime_get(); 70 map_delta = ktime_sub(map_etime, map_stime); 71 72 /* Pretend DMA is transmitting */ 73 ndelay(map->bparam.dma_trans_ns); 74 75 unmap_stime = ktime_get(); 76 dma_unmap_single(map->dev, dma_addr, size, map->dir); 77 unmap_etime = ktime_get(); 78 unmap_delta = ktime_sub(unmap_etime, unmap_stime); 79 80 /* calculate sum and sum of squares */ 81 82 map_100ns = div64_ul(map_delta, 100); 83 unmap_100ns = div64_ul(unmap_delta, 100); 84 map_sq = map_100ns * map_100ns; 85 unmap_sq = unmap_100ns * unmap_100ns; 86 87 atomic64_add(map_100ns, &map->sum_map_100ns); 88 atomic64_add(unmap_100ns, &map->sum_unmap_100ns); 89 atomic64_add(map_sq, &map->sum_sq_map); 90 atomic64_add(unmap_sq, &map->sum_sq_unmap); 91 atomic64_inc(&map->loops); 92 93 /* 94 * We may test for a long time so periodically check whether 95 * we need to schedule to avoid starving the others. Otherwise 96 * we may hangup the kernel in a non-preemptible kernel when 97 * the test kthreads number >= CPU number, the test kthreads 98 * will run endless on every CPU since the thread resposible 99 * for notifying the kthread stop (in do_map_benchmark()) 100 * could not be scheduled. 101 * 102 * Note this may degrade the test concurrency since the test 103 * threads may need to share the CPU time with other load 104 * in the system. So it's recommended to run this benchmark 105 * on an idle system. 106 */ 107 cond_resched(); 108 } 109 110 out: 111 free_pages_exact(buf, size); 112 return ret; 113 } 114 115 static int do_map_benchmark(struct map_benchmark_data *map) 116 { 117 struct task_struct **tsk; 118 int threads = map->bparam.threads; 119 int node = map->bparam.node; 120 u64 loops; 121 int ret = 0; 122 int i; 123 124 tsk = kmalloc_array(threads, sizeof(*tsk), GFP_KERNEL); 125 if (!tsk) 126 return -ENOMEM; 127 128 get_device(map->dev); 129 130 for (i = 0; i < threads; i++) { 131 tsk[i] = kthread_create_on_node(map_benchmark_thread, map, 132 map->bparam.node, "dma-map-benchmark/%d", i); 133 if (IS_ERR(tsk[i])) { 134 pr_err("create dma_map thread failed\n"); 135 ret = PTR_ERR(tsk[i]); 136 while (--i >= 0) 137 kthread_stop(tsk[i]); 138 goto out; 139 } 140 141 if (node != NUMA_NO_NODE) 142 kthread_bind_mask(tsk[i], cpumask_of_node(node)); 143 } 144 145 /* clear the old value in the previous benchmark */ 146 atomic64_set(&map->sum_map_100ns, 0); 147 atomic64_set(&map->sum_unmap_100ns, 0); 148 atomic64_set(&map->sum_sq_map, 0); 149 atomic64_set(&map->sum_sq_unmap, 0); 150 atomic64_set(&map->loops, 0); 151 152 for (i = 0; i < threads; i++) { 153 get_task_struct(tsk[i]); 154 wake_up_process(tsk[i]); 155 } 156 157 msleep_interruptible(map->bparam.seconds * 1000); 158 159 /* wait for the completion of all started benchmark threads */ 160 for (i = 0; i < threads; i++) { 161 int kthread_ret = kthread_stop_put(tsk[i]); 162 163 if (kthread_ret) 164 ret = kthread_ret; 165 } 166 167 if (ret) 168 goto out; 169 170 loops = atomic64_read(&map->loops); 171 if (likely(loops > 0)) { 172 u64 map_variance, unmap_variance; 173 u64 sum_map = atomic64_read(&map->sum_map_100ns); 174 u64 sum_unmap = atomic64_read(&map->sum_unmap_100ns); 175 u64 sum_sq_map = atomic64_read(&map->sum_sq_map); 176 u64 sum_sq_unmap = atomic64_read(&map->sum_sq_unmap); 177 178 /* average latency */ 179 map->bparam.avg_map_100ns = div64_u64(sum_map, loops); 180 map->bparam.avg_unmap_100ns = div64_u64(sum_unmap, loops); 181 182 /* standard deviation of latency */ 183 map_variance = div64_u64(sum_sq_map, loops) - 184 map->bparam.avg_map_100ns * 185 map->bparam.avg_map_100ns; 186 unmap_variance = div64_u64(sum_sq_unmap, loops) - 187 map->bparam.avg_unmap_100ns * 188 map->bparam.avg_unmap_100ns; 189 map->bparam.map_stddev = int_sqrt64(map_variance); 190 map->bparam.unmap_stddev = int_sqrt64(unmap_variance); 191 } 192 193 out: 194 put_device(map->dev); 195 kfree(tsk); 196 return ret; 197 } 198 199 static long map_benchmark_ioctl(struct file *file, unsigned int cmd, 200 unsigned long arg) 201 { 202 struct map_benchmark_data *map = file->private_data; 203 void __user *argp = (void __user *)arg; 204 u64 old_dma_mask; 205 int ret; 206 207 if (copy_from_user(&map->bparam, argp, sizeof(map->bparam))) 208 return -EFAULT; 209 210 switch (cmd) { 211 case DMA_MAP_BENCHMARK: 212 if (map->bparam.threads == 0 || 213 map->bparam.threads > DMA_MAP_MAX_THREADS) { 214 pr_err("invalid thread number\n"); 215 return -EINVAL; 216 } 217 218 if (map->bparam.seconds == 0 || 219 map->bparam.seconds > DMA_MAP_MAX_SECONDS) { 220 pr_err("invalid duration seconds\n"); 221 return -EINVAL; 222 } 223 224 if (map->bparam.dma_trans_ns > DMA_MAP_MAX_TRANS_DELAY) { 225 pr_err("invalid transmission delay\n"); 226 return -EINVAL; 227 } 228 229 if (map->bparam.node != NUMA_NO_NODE && 230 (map->bparam.node < 0 || map->bparam.node >= MAX_NUMNODES || 231 !node_possible(map->bparam.node))) { 232 pr_err("invalid numa node\n"); 233 return -EINVAL; 234 } 235 236 if (map->bparam.granule < 1 || map->bparam.granule > 1024) { 237 pr_err("invalid granule size\n"); 238 return -EINVAL; 239 } 240 241 switch (map->bparam.dma_dir) { 242 case DMA_MAP_BIDIRECTIONAL: 243 map->dir = DMA_BIDIRECTIONAL; 244 break; 245 case DMA_MAP_FROM_DEVICE: 246 map->dir = DMA_FROM_DEVICE; 247 break; 248 case DMA_MAP_TO_DEVICE: 249 map->dir = DMA_TO_DEVICE; 250 break; 251 default: 252 pr_err("invalid DMA direction\n"); 253 return -EINVAL; 254 } 255 256 old_dma_mask = dma_get_mask(map->dev); 257 258 ret = dma_set_mask(map->dev, 259 DMA_BIT_MASK(map->bparam.dma_bits)); 260 if (ret) { 261 pr_err("failed to set dma_mask on device %s\n", 262 dev_name(map->dev)); 263 return -EINVAL; 264 } 265 266 ret = do_map_benchmark(map); 267 268 /* 269 * restore the original dma_mask as many devices' dma_mask are 270 * set by architectures, acpi, busses. When we bind them back 271 * to their original drivers, those drivers shouldn't see 272 * dma_mask changed by benchmark 273 */ 274 dma_set_mask(map->dev, old_dma_mask); 275 276 if (ret) 277 return ret; 278 break; 279 default: 280 return -EINVAL; 281 } 282 283 if (copy_to_user(argp, &map->bparam, sizeof(map->bparam))) 284 return -EFAULT; 285 286 return ret; 287 } 288 289 static const struct file_operations map_benchmark_fops = { 290 .open = simple_open, 291 .unlocked_ioctl = map_benchmark_ioctl, 292 }; 293 294 static void map_benchmark_remove_debugfs(void *data) 295 { 296 struct map_benchmark_data *map = (struct map_benchmark_data *)data; 297 298 debugfs_remove(map->debugfs); 299 } 300 301 static int __map_benchmark_probe(struct device *dev) 302 { 303 struct dentry *entry; 304 struct map_benchmark_data *map; 305 int ret; 306 307 map = devm_kzalloc(dev, sizeof(*map), GFP_KERNEL); 308 if (!map) 309 return -ENOMEM; 310 map->dev = dev; 311 312 ret = devm_add_action(dev, map_benchmark_remove_debugfs, map); 313 if (ret) { 314 pr_err("Can't add debugfs remove action\n"); 315 return ret; 316 } 317 318 /* 319 * we only permit a device bound with this driver, 2nd probe 320 * will fail 321 */ 322 entry = debugfs_create_file("dma_map_benchmark", 0600, NULL, map, 323 &map_benchmark_fops); 324 if (IS_ERR(entry)) 325 return PTR_ERR(entry); 326 map->debugfs = entry; 327 328 return 0; 329 } 330 331 static int map_benchmark_platform_probe(struct platform_device *pdev) 332 { 333 return __map_benchmark_probe(&pdev->dev); 334 } 335 336 static struct platform_driver map_benchmark_platform_driver = { 337 .driver = { 338 .name = "dma_map_benchmark", 339 }, 340 .probe = map_benchmark_platform_probe, 341 }; 342 343 static int 344 map_benchmark_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id) 345 { 346 return __map_benchmark_probe(&pdev->dev); 347 } 348 349 static struct pci_driver map_benchmark_pci_driver = { 350 .name = "dma_map_benchmark", 351 .probe = map_benchmark_pci_probe, 352 }; 353 354 static int __init map_benchmark_init(void) 355 { 356 int ret; 357 358 ret = pci_register_driver(&map_benchmark_pci_driver); 359 if (ret) 360 return ret; 361 362 ret = platform_driver_register(&map_benchmark_platform_driver); 363 if (ret) { 364 pci_unregister_driver(&map_benchmark_pci_driver); 365 return ret; 366 } 367 368 return 0; 369 } 370 371 static void __exit map_benchmark_cleanup(void) 372 { 373 platform_driver_unregister(&map_benchmark_platform_driver); 374 pci_unregister_driver(&map_benchmark_pci_driver); 375 } 376 377 module_init(map_benchmark_init); 378 module_exit(map_benchmark_cleanup); 379 380 MODULE_AUTHOR("Barry Song <song.bao.hua@hisilicon.com>"); 381 MODULE_DESCRIPTION("dma_map benchmark driver"); 382