// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright (C) 2020 HiSilicon Limited.
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/debugfs.h>
#include <linux/delay.h>
#include <linux/device.h>
#include <linux/dma-mapping.h>
#include <linux/kernel.h>
#include <linux/kthread.h>
#include <linux/map_benchmark.h>
#include <linux/math64.h>
#include <linux/module.h>
#include <linux/pci.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/timekeeping.h>
struct map_benchmark_data {
struct map_benchmark bparam;
struct device *dev;
struct dentry *debugfs;
enum dma_data_direction dir;
atomic64_t sum_map_100ns;
atomic64_t sum_unmap_100ns;
atomic64_t sum_sq_map;
atomic64_t sum_sq_unmap;
atomic64_t loops;
};
static int map_benchmark_thread(void *data)
{
void *buf;
dma_addr_t dma_addr;
struct map_benchmark_data *map = data;
int npages = map->bparam.granule;
u64 size = npages * PAGE_SIZE;
int ret = 0;
buf = alloc_pages_exact(size, GFP_KERNEL);
if (!buf)
return -ENOMEM;
while (!kthread_should_stop()) {
u64 map_100ns, unmap_100ns, map_sq, unmap_sq;
ktime_t map_stime, map_etime, unmap_stime, unmap_etime;
ktime_t map_delta, unmap_delta;
/*
* for a non-coherent device, if we don't stain them in the
* cache, this will give an underestimate of the real-world
* overhead of BIDIRECTIONAL or TO_DEVICE mappings;
* 66 means evertything goes well! 66 is lucky.
*/
if (map->dir != DMA_FROM_DEVICE)
memset(buf, 0x66, size);
map_stime = ktime_get();
dma_addr = dma_map_single(map->dev, buf, size, map->dir);
if (unlikely(dma_mapping_error(map->dev, dma_addr))) {
pr_err("dma_map_single failed on %s\n",
dev_name(map->dev));
ret = -ENOMEM;
goto out;
}
map_etime = ktime_get();
map_delta = ktime_sub(map_etime, map_stime);
/* Pretend DMA is transmitting */
ndelay(map->bparam.dma_trans_ns);
unmap_stime = ktime_get();
dma_unmap_single(map->dev, dma_addr, size, map->dir);
unmap_etime = ktime_get();
unmap_delta = ktime_sub(unmap_etime, unmap_stime);
/* calculate sum and sum of squares */
map_100ns = div64_ul(map_delta, 100);
unmap_100ns = div64_ul(unmap_delta, 100);
map_sq = map_100ns * map_100ns;
unmap_sq = unmap_100ns * unmap_100ns;
atomic64_add(map_100ns, &map->sum_map_100ns);
atomic64_add(unmap_100ns, &map->sum_unmap_100ns);
atomic64_add(map_sq, &map->sum_sq_map);
atomic64_add(unmap_sq, &map->sum_sq_unmap);
atomic64_inc(&map->loops);
/*
* We may test for a long time so periodically check whether
* we need to schedule to avoid starving the others. Otherwise
* we may hangup the kernel in a non-preemptible kernel when
* the test kthreads number >= CPU number, the test kthreads
* will run endless on every CPU since the thread resposible
* for notifying the kthread stop (in do_map_benchmark())
* could not be scheduled.
*
* Note this may degrade the test concurrency since the test
* threads may need to share the CPU time with other load
* in the system. So it's recommended to run this benchmark
* on an idle system.
*/
cond_resched();
}
out:
free_pages_exact(buf, size);
return ret;
}
static int do_map_benchmark(struct map_benchmark_data *map)
{
struct task_struct **tsk;
int threads = map->bparam.threads;
int node = map->bparam.node;
u64 loops;
int ret = 0;
int i;
tsk = kmalloc_array(threads, sizeof(*tsk), GFP_KERNEL);
if (!tsk)
return -ENOMEM;
get_device(map->dev);
for (i = 0; i < threads; i++) {
tsk[i] = kthread_create_on_node(map_benchmark_thread, map,
map->bparam.node, "dma-map-benchmark/%d", i);
if (IS_ERR(tsk[i])) {
pr_err("create dma_map thread failed\n");
ret = PTR_ERR(tsk[i]);
while (--i >= 0)
kthread_stop(tsk[i]);
goto out;
}
if (node != NUMA_NO_NODE)
kthread_bind_mask(tsk[i], cpumask_of_node(node));
}
/* clear the old value in the previous benchmark */
atomic64_set(&map->sum_map_100ns, 0);
atomic64_set(&map->sum_unmap_100ns, 0);
atomic64_set(&map->sum_sq_map, 0);
atomic64_set(&map->sum_sq_unmap, 0);
atomic64_set(&map->loops, 0);
for (i = 0; i < threads; i++) {
get_task_struct(tsk[i]);
wake_up_process(tsk[i]);
}
msleep_interruptible(map->bparam.seconds * 1000);
/* wait for the completion of all started benchmark threads */
for (i = 0; i < threads; i++) {
int kthread_ret = kthread_stop_put(tsk[i]);
if (kthread_ret)
ret = kthread_ret;
}
if (ret)
goto out;
loops = atomic64_read(&map->loops);
if (likely(loops > 0)) {
u64 map_variance, unmap_variance;
u64 sum_map = atomic64_read(&map->sum_map_100ns);
u64 sum_unmap = atomic64_read(&map->sum_unmap_100ns);
u64 sum_sq_map = atomic64_read(&map->sum_sq_map);
u64 sum_sq_unmap = atomic64_read(&map->sum_sq_unmap);
/* average latency */
map->bparam.avg_map_100ns = div64_u64(sum_map, loops);
map->bparam.avg_unmap_100ns = div64_u64(sum_unmap, loops);
/* standard deviation of latency */
map_variance = div64_u64(sum_sq_map, loops) -
map->bparam.avg_map_100ns *
map->bparam.avg_map_100ns;
unmap_variance = div64_u64(sum_sq_unmap, loops) -
map->bparam.avg_unmap_100ns *
map->bparam.avg_unmap_100ns;
map->bparam.map_stddev = int_sqrt64(map_variance);
map->bparam.unmap_stddev = int_sqrt64(unmap_variance);
}
out:
put_device(map->dev);
kfree(tsk);
return ret;
}
static long map_benchmark_ioctl(struct file *file, unsigned int cmd,
unsigned long arg)
{
struct map_benchmark_data *map = file->private_data;
void __user *argp = (void __user *)arg;
u64 old_dma_mask;
int ret;
if (copy_from_user(&map->bparam, argp, sizeof(map->bparam)))
return -EFAULT;
switch (cmd) {
case DMA_MAP_BENCHMARK:
if (map->bparam.threads == 0 ||
map->bparam.threads > DMA_MAP_MAX_THREADS) {
pr_err("invalid thread number\n");
return -EINVAL;
}
if (map->bparam.seconds == 0 ||
map->bparam.seconds > DMA_MAP_MAX_SECONDS) {
pr_err("invalid duration seconds\n");
return -EINVAL;
}
if (map->bparam.dma_trans_ns > DMA_MAP_MAX_TRANS_DELAY) {
pr_err("invalid transmission delay\n");
return -EINVAL;
}
if (map->bparam.node != NUMA_NO_NODE &&
(map->bparam.node < 0 || map->bparam.node >= MAX_NUMNODES ||
!node_possible(map->bparam.node))) {
pr_err("invalid numa node\n");
return -EINVAL;
}
if (map->bparam.granule < 1 || map->bparam.granule > 1024) {
pr_err("invalid granule size\n");
return -EINVAL;
}
switch (map->bparam.dma_dir) {
case DMA_MAP_BIDIRECTIONAL:
map->dir = DMA_BIDIRECTIONAL;
break;
case DMA_MAP_FROM_DEVICE:
map->dir = DMA_FROM_DEVICE;
break;
case DMA_MAP_TO_DEVICE:
map->dir = DMA_TO_DEVICE;
break;
default:
pr_err("invalid DMA direction\n");
return -EINVAL;
}
old_dma_mask = dma_get_mask(map->dev);
ret = dma_set_mask(map->dev,
DMA_BIT_MASK(map->bparam.dma_bits));
if (ret) {
pr_err("failed to set dma_mask on device %s\n",
dev_name(map->dev));
return -EINVAL;
}
ret = do_map_benchmark(map);
/*
* restore the original dma_mask as many devices' dma_mask are
* set by architectures, acpi, busses. When we bind them back
* to their original drivers, those drivers shouldn't see
* dma_mask changed by benchmark
*/
dma_set_mask(map->dev, old_dma_mask);
if (ret)
return ret;
break;
default:
return -EINVAL;
}
if (copy_to_user(argp, &map->bparam, sizeof(map->bparam)))
return -EFAULT;
return ret;
}
static const struct file_operations map_benchmark_fops = {
.open = simple_open,
.unlocked_ioctl = map_benchmark_ioctl,
};
static void map_benchmark_remove_debugfs(void *data)
{
struct map_benchmark_data *map = (struct map_benchmark_data *)data;
debugfs_remove(map->debugfs);
}
static int __map_benchmark_probe(struct device *dev)
{
struct dentry *entry;
struct map_benchmark_data *map;
int ret;
map = devm_kzalloc(dev, sizeof(*map), GFP_KERNEL);
if (!map)
return -ENOMEM;
map->dev = dev;
ret = devm_add_action(dev, map_benchmark_remove_debugfs, map);
if (ret) {
pr_err("Can't add debugfs remove action\n");
return ret;
}
/*
* we only permit a device bound with this driver, 2nd probe
* will fail
*/
entry = debugfs_create_file("dma_map_benchmark", 0600, NULL, map,
&map_benchmark_fops);
if (IS_ERR(entry))
return PTR_ERR(entry);
map->debugfs = entry;
return 0;
}
static int map_benchmark_platform_probe(struct platform_device *pdev)
{
return __map_benchmark_probe(&pdev->dev);
}
static struct platform_driver map_benchmark_platform_driver = {
.driver = {
.name = "dma_map_benchmark",
},
.probe = map_benchmark_platform_probe,
};
static int
map_benchmark_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id)
{
return __map_benchmark_probe(&pdev->dev);
}
static struct pci_driver map_benchmark_pci_driver = {
.name = "dma_map_benchmark",
.probe = map_benchmark_pci_probe,
};
static int __init map_benchmark_init(void)
{
int ret;
ret = pci_register_driver(&map_benchmark_pci_driver);
if (ret)
return ret;
ret = platform_driver_register(&map_benchmark_platform_driver);
if (ret) {
pci_unregister_driver(&map_benchmark_pci_driver);
return ret;
}
return 0;
}
static void __exit map_benchmark_cleanup(void)
{
platform_driver_unregister(&map_benchmark_platform_driver);
pci_unregister_driver(&map_benchmark_pci_driver);
}
module_init(map_benchmark_init);
module_exit(map_benchmark_cleanup);
MODULE_AUTHOR("Barry Song <[email protected]>");
MODULE_DESCRIPTION("dma_map benchmark driver");
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