Re: [Intel-gfx] [PATCH 06/12] drm/i915/guc: Use streaming loads to speed up dumping the guc log

[John Harrison]

On 7/12/2022 16:31, john.c.harri...@intel.com wrote:

From: Chris Wilson <chris.p.wil...@intel.com>

Use a temporary page and mempy_from_wc to reduce the time it takes to
dump the guc log to debugfs.

Signed-off-by: Chris Wilson <chris.p.wil...@intel.com>

Reviewed-by: John Harrison <john.c.harri...@intel.com>

---
  drivers/gpu/drm/i915/gt/uc/intel_guc_log.c | 24 ++++++++++++++++------
  1 file changed, 18 insertions(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/i915/gt/uc/intel_guc_log.c 
b/drivers/gpu/drm/i915/gt/uc/intel_guc_log.c
index 45f62cdabe356..ff091adb56096 100644
--- a/drivers/gpu/drm/i915/gt/uc/intel_guc_log.c
+++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_log.c
@@ -749,8 +749,9 @@ int intel_guc_log_dump(struct intel_guc_log *log, struct 
drm_printer *p,
        struct intel_guc *guc = log_to_guc(log);
        struct intel_uc *uc = container_of(guc, struct intel_uc, guc);
        struct drm_i915_gem_object *obj = NULL;
-       u32 *map;
-       int i = 0;
+       void *map;
+       u32 *page;
+       int i, j;

if (!intel_guc_is_supported(guc))

                return -ENODEV;
@@ -763,23 +764,34 @@ int intel_guc_log_dump(struct intel_guc_log *log, struct 
drm_printer *p,
        if (!obj)
                return 0;

+ page = (u32 *)__get_free_page(GFP_KERNEL);

+       if (!page)
+               return -ENOMEM;
+
        intel_guc_dump_time_info(guc, p);

map = i915_gem_object_pin_map_unlocked(obj, I915_MAP_WC);

        if (IS_ERR(map)) {
                DRM_DEBUG("Failed to pin object\n");
                drm_puts(p, "(log data unaccessible)\n");
+               free_page((unsigned long)page);
                return PTR_ERR(map);
        }

- for (i = 0; i < obj->base.size / sizeof(u32); i += 4)

-               drm_printf(p, "0x%08x 0x%08x 0x%08x 0x%08x\n",
-                          *(map + i), *(map + i + 1),
-                          *(map + i + 2), *(map + i + 3));
+       for (i = 0; i < obj->base.size; i += PAGE_SIZE) {
+               if (!i915_memcpy_from_wc(page, map + i, PAGE_SIZE))
+                       memcpy(page, map + i, PAGE_SIZE);
+
+               for (j = 0; j < PAGE_SIZE / sizeof(u32); j += 4)
+                       drm_printf(p, "0x%08x 0x%08x 0x%08x 0x%08x\n",
+                                  *(page + j + 0), *(page + j + 1),
+                                  *(page + j + 2), *(page + j + 3));
+       }

drm_puts(p, "\n"); i915_gem_object_unpin_map(obj);

+       free_page((unsigned long)page);

return 0;

  }