drm/mm: add ig_frag selftest

This patch introduces fragmentation in the address range
and measures time taken by 10k and 20k insertions. ig_frag()
will fail if the time taken by 20k insertions takes more than
4 times of 10k insertions as we know that insertions should at
most scale quadratically.

v2:
introduce fragmentation by freeing every other node.
only test bottom-up and top-down for now.

v3:
fix incorrect mode check

Signed-off-by: Nirmoy Das <nirmoy.das@amd.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Christian König <christian.koenig@amd.com>
Link: https://patchwork.freedesktop.org/patch/369076/

diff --git a/drivers/gpu/drm/selftests/drm_mm_selftests.h b/drivers/gpu/drm/selftests/drm_mm_selftests.h
index 6b943ea..8c87c96 100644 (file)
--- a/drivers/gpu/drm/selftests/drm_mm_selftests.h
+++ b/drivers/gpu/drm/selftests/drm_mm_selftests.h
@@ -14,6 +14,7 @@ selftest(insert, igt_insert)
 selftest(replace, igt_replace)
 selftest(insert_range, igt_insert_range)
 selftest(align, igt_align)
+selftest(frag, igt_frag)
 selftest(align32, igt_align32)
 selftest(align64, igt_align64)
 selftest(evict, igt_evict)

diff --git a/drivers/gpu/drm/selftests/test-drm_mm.c b/drivers/gpu/drm/selftests/test-drm_mm.c
index 9aabe82..ca5f35d 100644 (file)
--- a/drivers/gpu/drm/selftests/test-drm_mm.c
+++ b/drivers/gpu/drm/selftests/test-drm_mm.c
@@ -10,6 +10,7 @@
 #include <linux/slab.h>
 #include <linux/random.h>
 #include <linux/vmalloc.h>
+#include <linux/ktime.h>
 
 #include <drm/drm_mm.h>
 
@@ -1033,6 +1034,129 @@ static int igt_insert_range(void *ignored)
        return 0;
 }
 
+static int prepare_igt_frag(struct drm_mm *mm,
+                           struct drm_mm_node *nodes,
+                           unsigned int num_insert,
+                           const struct insert_mode *mode)
+{
+       unsigned int size = 4096;
+       unsigned int i;
+       u64 ret = -EINVAL;
+
+       for (i = 0; i < num_insert; i++) {
+               if (!expect_insert(mm, &nodes[i], size, 0, i,
+                                  mode) != 0) {
+                       pr_err("%s insert failed\n", mode->name);
+                       goto out;
+               }
+       }
+
+       /* introduce fragmentation by freeing every other node */
+       for (i = 0; i < num_insert; i++) {
+               if (i % 2 == 0)
+                       drm_mm_remove_node(&nodes[i]);
+       }
+
+out:
+       return ret;
+
+}
+
+static u64 get_insert_time(struct drm_mm *mm,
+                          unsigned int num_insert,
+                          struct drm_mm_node *nodes,
+                          const struct insert_mode *mode)
+{
+       unsigned int size = 8192;
+       ktime_t start;
+       unsigned int i;
+       u64 ret = -EINVAL;
+
+       start = ktime_get();
+       for (i = 0; i < num_insert; i++) {
+               if (!expect_insert(mm, &nodes[i], size, 0, i, mode) != 0) {
+                       pr_err("%s insert failed\n", mode->name);
+                       goto out;
+               }
+       }
+
+       ret = ktime_to_ns(ktime_sub(ktime_get(), start));
+
+out:
+       return ret;
+
+}
+
+static int igt_frag(void *ignored)
+{
+       struct drm_mm mm;
+       const struct insert_mode *mode;
+       struct drm_mm_node *nodes, *node, *next;
+       unsigned int insert_size = 10000;
+       unsigned int scale_factor = 4;
+       int ret = -EINVAL;
+
+       /* We need 4 * insert_size nodes to hold intermediate allocated
+        * drm_mm nodes.
+        * 1 times for prepare_igt_frag()
+        * 1 times for get_insert_time()
+        * 2 times for get_insert_time()
+        */
+       nodes = vzalloc(array_size(insert_size * 4, sizeof(*nodes)));
+       if (!nodes)
+               return -ENOMEM;
+
+       /* For BOTTOMUP and TOPDOWN, we first fragment the
+        * address space using prepare_igt_frag() and then try to verify
+        * that that insertions scale quadratically from 10k to 20k insertions
+        */
+       drm_mm_init(&mm, 1, U64_MAX - 2);
+       for (mode = insert_modes; mode->name; mode++) {
+               u64 insert_time1, insert_time2;
+
+               if (mode->mode != DRM_MM_INSERT_LOW &&
+                   mode->mode != DRM_MM_INSERT_HIGH)
+                       continue;
+
+               ret = prepare_igt_frag(&mm, nodes, insert_size, mode);
+               if (!ret)
+                       goto err;
+
+               insert_time1 = get_insert_time(&mm, insert_size,
+                                              nodes + insert_size, mode);
+               if (insert_time1 < 0)
+                       goto err;
+
+               insert_time2 = get_insert_time(&mm, (insert_size * 2),
+                                              nodes + insert_size * 2, mode);
+               if (insert_time2 < 0)
+                       goto err;
+
+               pr_info("%s fragmented insert of %u and %u insertions took %llu and %llu nsecs\n",
+                       mode->name, insert_size, insert_size * 2,
+                       insert_time1, insert_time2);
+
+               if (insert_time2 > (scale_factor * insert_time1)) {
+                       pr_err("%s fragmented insert took %llu nsecs more\n",
+                              mode->name,
+                              insert_time2 - (scale_factor * insert_time1));
+                       goto err;
+               }
+
+               drm_mm_for_each_node_safe(node, next, &mm)
+                       drm_mm_remove_node(node);
+       }
+
+       ret = 0;
+err:
+       drm_mm_for_each_node_safe(node, next, &mm)
+               drm_mm_remove_node(node);
+       drm_mm_takedown(&mm);
+       vfree(nodes);
+
+       return ret;
+}
+
 static int igt_align(void *ignored)
 {
        const struct insert_mode *mode;