1 // SPDX-License-Identifier: GPL-2.0-only
3 * Copyright (C) 2020 Hisilicon Limited.
6 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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/math64.h>
15 #include <linux/module.h>
16 #include <linux/pci.h>
17 #include <linux/platform_device.h>
18 #include <linux/slab.h>
19 #include <linux/timekeeping.h>
21 #define DMA_MAP_BENCHMARK _IOWR('d', 1, struct map_benchmark)
22 #define DMA_MAP_MAX_THREADS 1024
23 #define DMA_MAP_MAX_SECONDS 300
24 #define DMA_MAP_MAX_TRANS_DELAY (10 * NSEC_PER_MSEC)
26 #define DMA_MAP_BIDIRECTIONAL 0
27 #define DMA_MAP_TO_DEVICE 1
28 #define DMA_MAP_FROM_DEVICE 2
30 struct map_benchmark {
31 __u64 avg_map_100ns; /* average map latency in 100ns */
32 __u64 map_stddev; /* standard deviation of map latency */
33 __u64 avg_unmap_100ns; /* as above */
35 __u32 threads; /* how many threads will do map/unmap in parallel */
36 __u32 seconds; /* how long the test will last */
37 __s32 node; /* which numa node this benchmark will run on */
38 __u32 dma_bits; /* DMA addressing capability */
39 __u32 dma_dir; /* DMA data direction */
40 __u32 dma_trans_ns; /* time for DMA transmission in ns */
41 __u8 expansion[80]; /* For future use */
44 struct map_benchmark_data {
45 struct map_benchmark bparam;
47 struct dentry *debugfs;
48 enum dma_data_direction dir;
49 atomic64_t sum_map_100ns;
50 atomic64_t sum_unmap_100ns;
51 atomic64_t sum_sq_map;
52 atomic64_t sum_sq_unmap;
56 static int map_benchmark_thread(void *data)
60 struct map_benchmark_data *map = data;
63 buf = (void *)__get_free_page(GFP_KERNEL);
67 while (!kthread_should_stop()) {
68 u64 map_100ns, unmap_100ns, map_sq, unmap_sq;
69 ktime_t map_stime, map_etime, unmap_stime, unmap_etime;
70 ktime_t map_delta, unmap_delta;
73 * for a non-coherent device, if we don't stain them in the
74 * cache, this will give an underestimate of the real-world
75 * overhead of BIDIRECTIONAL or TO_DEVICE mappings;
76 * 66 means evertything goes well! 66 is lucky.
78 if (map->dir != DMA_FROM_DEVICE)
79 memset(buf, 0x66, PAGE_SIZE);
81 map_stime = ktime_get();
82 dma_addr = dma_map_single(map->dev, buf, PAGE_SIZE, map->dir);
83 if (unlikely(dma_mapping_error(map->dev, dma_addr))) {
84 pr_err("dma_map_single failed on %s\n",
89 map_etime = ktime_get();
90 map_delta = ktime_sub(map_etime, map_stime);
92 /* Pretend DMA is transmitting */
93 ndelay(map->bparam.dma_trans_ns);
95 unmap_stime = ktime_get();
96 dma_unmap_single(map->dev, dma_addr, PAGE_SIZE, map->dir);
97 unmap_etime = ktime_get();
98 unmap_delta = ktime_sub(unmap_etime, unmap_stime);
100 /* calculate sum and sum of squares */
102 map_100ns = div64_ul(map_delta, 100);
103 unmap_100ns = div64_ul(unmap_delta, 100);
104 map_sq = map_100ns * map_100ns;
105 unmap_sq = unmap_100ns * unmap_100ns;
107 atomic64_add(map_100ns, &map->sum_map_100ns);
108 atomic64_add(unmap_100ns, &map->sum_unmap_100ns);
109 atomic64_add(map_sq, &map->sum_sq_map);
110 atomic64_add(unmap_sq, &map->sum_sq_unmap);
111 atomic64_inc(&map->loops);
115 free_page((unsigned long)buf);
119 static int do_map_benchmark(struct map_benchmark_data *map)
121 struct task_struct **tsk;
122 int threads = map->bparam.threads;
123 int node = map->bparam.node;
124 const cpumask_t *cpu_mask = cpumask_of_node(node);
129 tsk = kmalloc_array(threads, sizeof(*tsk), GFP_KERNEL);
133 get_device(map->dev);
135 for (i = 0; i < threads; i++) {
136 tsk[i] = kthread_create_on_node(map_benchmark_thread, map,
137 map->bparam.node, "dma-map-benchmark/%d", i);
138 if (IS_ERR(tsk[i])) {
139 pr_err("create dma_map thread failed\n");
140 ret = PTR_ERR(tsk[i]);
144 if (node != NUMA_NO_NODE)
145 kthread_bind_mask(tsk[i], cpu_mask);
148 /* clear the old value in the previous benchmark */
149 atomic64_set(&map->sum_map_100ns, 0);
150 atomic64_set(&map->sum_unmap_100ns, 0);
151 atomic64_set(&map->sum_sq_map, 0);
152 atomic64_set(&map->sum_sq_unmap, 0);
153 atomic64_set(&map->loops, 0);
155 for (i = 0; i < threads; i++) {
156 get_task_struct(tsk[i]);
157 wake_up_process(tsk[i]);
160 msleep_interruptible(map->bparam.seconds * 1000);
162 /* wait for the completion of benchmark threads */
163 for (i = 0; i < threads; i++) {
164 ret = kthread_stop(tsk[i]);
169 loops = atomic64_read(&map->loops);
170 if (likely(loops > 0)) {
171 u64 map_variance, unmap_variance;
172 u64 sum_map = atomic64_read(&map->sum_map_100ns);
173 u64 sum_unmap = atomic64_read(&map->sum_unmap_100ns);
174 u64 sum_sq_map = atomic64_read(&map->sum_sq_map);
175 u64 sum_sq_unmap = atomic64_read(&map->sum_sq_unmap);
177 /* average latency */
178 map->bparam.avg_map_100ns = div64_u64(sum_map, loops);
179 map->bparam.avg_unmap_100ns = div64_u64(sum_unmap, loops);
181 /* standard deviation of latency */
182 map_variance = div64_u64(sum_sq_map, loops) -
183 map->bparam.avg_map_100ns *
184 map->bparam.avg_map_100ns;
185 unmap_variance = div64_u64(sum_sq_unmap, loops) -
186 map->bparam.avg_unmap_100ns *
187 map->bparam.avg_unmap_100ns;
188 map->bparam.map_stddev = int_sqrt64(map_variance);
189 map->bparam.unmap_stddev = int_sqrt64(unmap_variance);
193 for (i = 0; i < threads; i++)
194 put_task_struct(tsk[i]);
195 put_device(map->dev);
200 static long map_benchmark_ioctl(struct file *file, unsigned int cmd,
203 struct map_benchmark_data *map = file->private_data;
204 void __user *argp = (void __user *)arg;
209 if (copy_from_user(&map->bparam, argp, sizeof(map->bparam)))
213 case DMA_MAP_BENCHMARK:
214 if (map->bparam.threads == 0 ||
215 map->bparam.threads > DMA_MAP_MAX_THREADS) {
216 pr_err("invalid thread number\n");
220 if (map->bparam.seconds == 0 ||
221 map->bparam.seconds > DMA_MAP_MAX_SECONDS) {
222 pr_err("invalid duration seconds\n");
226 if (map->bparam.dma_trans_ns > DMA_MAP_MAX_TRANS_DELAY) {
227 pr_err("invalid transmission delay\n");
231 if (map->bparam.node != NUMA_NO_NODE &&
232 !node_possible(map->bparam.node)) {
233 pr_err("invalid numa node\n");
237 switch (map->bparam.dma_dir) {
238 case DMA_MAP_BIDIRECTIONAL:
239 map->dir = DMA_BIDIRECTIONAL;
241 case DMA_MAP_FROM_DEVICE:
242 map->dir = DMA_FROM_DEVICE;
244 case DMA_MAP_TO_DEVICE:
245 map->dir = DMA_TO_DEVICE;
248 pr_err("invalid DMA direction\n");
252 old_dma_mask = dma_get_mask(map->dev);
254 ret = dma_set_mask(map->dev,
255 DMA_BIT_MASK(map->bparam.dma_bits));
257 pr_err("failed to set dma_mask on device %s\n",
262 ret = do_map_benchmark(map);
265 * restore the original dma_mask as many devices' dma_mask are
266 * set by architectures, acpi, busses. When we bind them back
267 * to their original drivers, those drivers shouldn't see
268 * dma_mask changed by benchmark
270 dma_set_mask(map->dev, old_dma_mask);
276 if (copy_to_user(argp, &map->bparam, sizeof(map->bparam)))
282 static const struct file_operations map_benchmark_fops = {
284 .unlocked_ioctl = map_benchmark_ioctl,
287 static void map_benchmark_remove_debugfs(void *data)
289 struct map_benchmark_data *map = (struct map_benchmark_data *)data;
291 debugfs_remove(map->debugfs);
294 static int __map_benchmark_probe(struct device *dev)
296 struct dentry *entry;
297 struct map_benchmark_data *map;
300 map = devm_kzalloc(dev, sizeof(*map), GFP_KERNEL);
305 ret = devm_add_action(dev, map_benchmark_remove_debugfs, map);
307 pr_err("Can't add debugfs remove action\n");
312 * we only permit a device bound with this driver, 2nd probe
315 entry = debugfs_create_file("dma_map_benchmark", 0600, NULL, map,
316 &map_benchmark_fops);
318 return PTR_ERR(entry);
319 map->debugfs = entry;
324 static int map_benchmark_platform_probe(struct platform_device *pdev)
326 return __map_benchmark_probe(&pdev->dev);
329 static struct platform_driver map_benchmark_platform_driver = {
331 .name = "dma_map_benchmark",
333 .probe = map_benchmark_platform_probe,
337 map_benchmark_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id)
339 return __map_benchmark_probe(&pdev->dev);
342 static struct pci_driver map_benchmark_pci_driver = {
343 .name = "dma_map_benchmark",
344 .probe = map_benchmark_pci_probe,
347 static int __init map_benchmark_init(void)
351 ret = pci_register_driver(&map_benchmark_pci_driver);
355 ret = platform_driver_register(&map_benchmark_platform_driver);
357 pci_unregister_driver(&map_benchmark_pci_driver);
364 static void __exit map_benchmark_cleanup(void)
366 platform_driver_unregister(&map_benchmark_platform_driver);
367 pci_unregister_driver(&map_benchmark_pci_driver);
370 module_init(map_benchmark_init);
371 module_exit(map_benchmark_cleanup);
373 MODULE_AUTHOR("Barry Song <song.bao.hua@hisilicon.com>");
374 MODULE_DESCRIPTION("dma_map benchmark driver");
375 MODULE_LICENSE("GPL");