[Linuxarm] Re: [PATCH] dma-mapping: benchmark: Add support for multi-pages map/unmap

-----Original Message----- From: chenxiang (M) Sent: Thursday, March 18, 2021 10:30 PM To: hch@lst.de; m.szyprowski@samsung.com; robin.murphy@arm.com; Song Bao Hua (Barry Song) song.bao.hua@hisilicon.com Cc: iommu@lists.linux-foundation.org; linuxarm@openeuler.org; linux-kselftest@vger.kernel.org; chenxiang (M) chenxiang66@hisilicon.com Subject: [PATCH] dma-mapping: benchmark: Add support for multi-pages map/unmap

From: Xiang Chen chenxiang66@hisilicon.com

Currently it only support one page map/unmap once a time for dma-map benchmark, but there are some other scenaries which need to support for multi-page map/unmap: for those multi-pages interfaces such as dma_alloc_coherent() and dma_map_sg(), the time spent on multi-pages map/unmap is not the time of a single page * npages (not linear) as it may use block description instead of page description when it is satified with the size such as 2M/1G, and also it can send a single TLB invalidation command to invalidate multi-pages instead of multi-times when RIL is enabled (which will short the time of unmap). So it is necessary to add support for multi-pages map/unmap.

Add a parameter "-g" to support multi-pages map/unmap.

Signed-off-by: Xiang Chen chenxiang66@hisilicon.com

Acked-by: Barry Song song.bao.hua@hisilicon.com

kernel/dma/map_benchmark.c | 21 ++++++++++++++------- tools/testing/selftests/dma/dma_map_benchmark.c | 20 ++++++++++++++++---- 2 files changed, 30 insertions(+), 11 deletions(-)

diff --git a/kernel/dma/map_benchmark.c b/kernel/dma/map_benchmark.c index e0e64f8..a5c1b01 100644 --- a/kernel/dma/map_benchmark.c +++ b/kernel/dma/map_benchmark.c @@ -38,7 +38,8 @@ struct map_benchmark { __u32 dma_bits; /* DMA addressing capability */ __u32 dma_dir; /* DMA data direction */ __u32 dma_trans_ns; /* time for DMA transmission in ns */

• __u8 expansion[80]; /* For future use */

• __u32 granule; /* how many PAGE_SIZE will do map/unmap once a time */
• __u8 expansion[76]; /* For future use */

};

struct map_benchmark_data { @@ -58,9 +59,11 @@ 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 = (void *)__get_free_page(GFP_KERNEL);

• buf = alloc_pages_exact(size, GFP_KERNEL); if (!buf) return -ENOMEM;

@@ -76,10 +79,10 @@ static int map_benchmark_thread(void *data) * 66 means evertything goes well! 66 is lucky. */ if (map->dir != DMA_FROM_DEVICE)

• 	memset(buf, 0x66, PAGE_SIZE);
  

• 	memset(buf, 0x66, size);
  
  

  map_stime = ktime_get();

• dma_addr = dma_map_single(map->dev, buf, PAGE_SIZE, map->dir);
  

• 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));

@@ -93,7 +96,7 @@ static int map_benchmark_thread(void *data) ndelay(map->bparam.dma_trans_ns);

unmap_stime = ktime_get();

• dma_unmap_single(map->dev, dma_addr, PAGE_SIZE, map->dir);
  

• dma_unmap_single(map->dev, dma_addr, size, map->dir);
  

  unmap_etime = ktime_get(); unmap_delta = ktime_sub(unmap_etime, unmap_stime);

@@ -112,7 +115,7 @@ static int map_benchmark_thread(void *data) }

out:

• free_page((unsigned long)buf);

• free_pages_exact(buf, size); return ret;

}

@@ -203,7 +206,6 @@ static long map_benchmark_ioctl(struct file *file, unsigned int cmd, 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)))

@@ -234,6 +236,11 @@ static long map_benchmark_ioctl(struct file *file, unsigned int cmd, 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;

diff --git a/tools/testing/selftests/dma/dma_map_benchmark.c b/tools/testing/selftests/dma/dma_map_benchmark.c index fb23ce9..6f2caa6 100644 --- a/tools/testing/selftests/dma/dma_map_benchmark.c +++ b/tools/testing/selftests/dma/dma_map_benchmark.c @@ -40,7 +40,8 @@ struct map_benchmark { __u32 dma_bits; /* DMA addressing capability */ __u32 dma_dir; /* DMA data direction */ __u32 dma_trans_ns; /* time for DMA transmission in ns */

• __u8 expansion[80]; /* For future use */

• __u32 granule; /* how many PAGE_SIZE will do map/unmap once a time */
• __u8 expansion[76]; /* For future use */

};

int main(int argc, char **argv) @@ -51,11 +52,13 @@ int main(int argc, char **argv) int threads = 1, seconds = 20, node = -1; /* default dma mask 32bit, bidirectional DMA */ int bits = 32, xdelay = 0, dir = DMA_MAP_BIDIRECTIONAL;

• /* default granule 1 PAGESIZE */

• int granule = 1;

  int cmd = DMA_MAP_BENCHMARK; char *p;

• while ((opt = getopt(argc, argv, "t:s:n:b:d:x:")) != -1) {

• while ((opt = getopt(argc, argv, "t:s:n:b:d:x:g:")) != -1) { switch (opt) { case 't': threads = atoi(optarg);

@@ -75,6 +78,9 @@ int main(int argc, char **argv) case 'x': xdelay = atoi(optarg); break;

• case 'g':
  

• 	granule = atoi(optarg);
  

• 	break;
  

  default: return -1; }

@@ -110,6 +116,11 @@ int main(int argc, char **argv) exit(1); }

• if (granule < 1 || granule > 1024) {

• fprintf(stderr, "invalid granule size\n");
  

• exit(1);
  

• }
• fd = open("/sys/kernel/debug/dma_map_benchmark", O_RDWR); if (fd == -1) { perror("open");

@@ -123,14 +134,15 @@ int main(int argc, char **argv) map.dma_bits = bits; map.dma_dir = dir; map.dma_trans_ns = xdelay;

• map.granule = granule;

  if (ioctl(fd, cmd, &map)) { perror("ioctl"); exit(1); }

• printf("dma mapping benchmark: threads:%d seconds:%d node:%d dir:%s\n",

• 	threads, seconds, node, dir[directions]);
  

• printf("dma mapping benchmark: threads:%d seconds:%d node:%d dir:%s

granule: %d\n",

• 	threads, seconds, node, dir[directions], granule);
  

  printf("average map latency(us):%.1f standard deviation:%.1f\n", map.avg_map_100ns/10.0, map.map_stddev/10.0); printf("average unmap latency(us):%.1f standard deviation:%.1f\n",

-- 2.8.1

Thanks Barry