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authorEric Anholt <eric@anholt.net>2008-10-21 00:10:54 -0700
committerEric Anholt <eric@anholt.net>2008-10-28 14:27:49 -0700
commit0e867312323fa51af324228b98bff4f49a813481 (patch)
treee2ebd033a8ecf9661d9c2936455ce2ff9ba5dccb /libdrm/intel
parente47ab7a5081e178bad385ce2e75b01474ea7aa4c (diff)
intel: Add dri_bufmgr_check_aperture support for bufmgr_gem.
This relies on a new kernel ioctl to get the available aperture size. In order to provide reasonable performance from dri_bufmgr_check_aperture, we now require that once a buffer has been used as the target of a relocation, it gets no further relocations added to it. This cuts the cost of check_aperture from 10% to 1% in the 3D driver with no code changes, but slightly complicates our plans for the 2D driver.
Diffstat (limited to 'libdrm/intel')
-rw-r--r--libdrm/intel/intel_bufmgr_gem.c137
1 files changed, 134 insertions, 3 deletions
diff --git a/libdrm/intel/intel_bufmgr_gem.c b/libdrm/intel/intel_bufmgr_gem.c
index 081eb2ad..dd74659a 100644
--- a/libdrm/intel/intel_bufmgr_gem.c
+++ b/libdrm/intel/intel_bufmgr_gem.c
@@ -94,6 +94,8 @@ typedef struct _dri_bufmgr_gem {
/** Array of lists of cached gem objects of power-of-two sizes */
struct dri_gem_bo_bucket cache_bucket[INTEL_GEM_BO_BUCKETS];
+
+ uint64_t gtt_size;
} dri_bufmgr_gem;
struct _dri_bo_gem {
@@ -134,6 +136,27 @@ struct _dri_bo_gem {
/** free list */
dri_bo_gem *next;
+
+ /**
+ * Boolean of whether this BO and its children have been included in
+ * the current dri_bufmgr_check_aperture_space() total.
+ */
+ char included_in_check_aperture;
+
+ /**
+ * Boolean of whether this buffer has been used as a relocation
+ * target and had its size accounted for, and thus can't have any
+ * further relocations added to it.
+ */
+ char used_as_reloc_target;
+
+ /**
+ * Size in bytes of this buffer and its relocation descendents.
+ *
+ * Used to avoid costly tree walking in dri_bufmgr_check_aperture in
+ * the common case.
+ */
+ int reloc_tree_size;
};
static void dri_gem_bo_reference_locked(dri_bo *bo);
@@ -333,6 +356,8 @@ dri_gem_bo_alloc(dri_bufmgr *bufmgr, const char *name,
bo_gem->name = name;
bo_gem->refcount = 1;
bo_gem->validate_index = -1;
+ bo_gem->reloc_tree_size = bo_gem->bo.size;
+ bo_gem->used_as_reloc_target = 0;
DBG("bo_create: buf %d (%s) %ldb\n",
bo_gem->gem_handle, bo_gem->name, size);
@@ -699,6 +724,15 @@ dri_gem_bo_emit_reloc(dri_bo *bo, uint32_t read_domains, uint32_t write_domain,
assert (offset <= bo->size - 4);
assert ((write_domain & (write_domain-1)) == 0);
+ /* Make sure that we're not adding a reloc to something whose size has
+ * already been accounted for.
+ */
+ assert(!bo_gem->used_as_reloc_target);
+ bo_gem->reloc_tree_size += target_bo_gem->reloc_tree_size;
+
+ /* Flag the target to disallow further relocations in it. */
+ target_bo_gem->used_as_reloc_target = 1;
+
bo_gem->relocs[bo_gem->reloc_count].offset = offset;
bo_gem->relocs[bo_gem->reloc_count].delta = delta;
bo_gem->relocs[bo_gem->reloc_count].target_handle =
@@ -933,13 +967,96 @@ intel_bufmgr_gem_enable_reuse(dri_bufmgr *bufmgr)
}
}
-/*
+/**
+ * Return the additional aperture space required by the tree of buffer objects
+ * rooted at bo.
+ */
+static int
+dri_gem_bo_get_aperture_space(dri_bo *bo)
+{
+ dri_bo_gem *bo_gem = (dri_bo_gem *)bo;
+ int i;
+ int total = 0;
+
+ if (bo == NULL || bo_gem->included_in_check_aperture)
+ return 0;
+
+ total += bo->size;
+ bo_gem->included_in_check_aperture = 1;
+
+ for (i = 0; i < bo_gem->reloc_count; i++)
+ total += dri_gem_bo_get_aperture_space(bo_gem->reloc_target_bo[i]);
+
+ return total;
+}
+
+/**
+ * Clear the flag set by dri_gem_bo_get_aperture_space() so we're ready for
+ * the next dri_bufmgr_check_aperture_space() call.
+ */
+static void
+dri_gem_bo_clear_aperture_space_flag(dri_bo *bo)
+{
+ dri_bo_gem *bo_gem = (dri_bo_gem *)bo;
+ int i;
+
+ if (bo == NULL || !bo_gem->included_in_check_aperture)
+ return;
+
+ bo_gem->included_in_check_aperture = 0;
+
+ for (i = 0; i < bo_gem->reloc_count; i++)
+ dri_gem_bo_clear_aperture_space_flag(bo_gem->reloc_target_bo[i]);
+}
+
+/**
+ * Return -1 if the batchbuffer should be flushed before attempting to
+ * emit rendering referencing the buffers pointed to by bo_array.
+ *
+ * This is required because if we try to emit a batchbuffer with relocations
+ * to a tree of buffers that won't simultaneously fit in the aperture,
+ * the rendering will return an error at a point where the software is not
+ * prepared to recover from it.
*
+ * However, we also want to emit the batchbuffer significantly before we reach
+ * the limit, as a series of batchbuffers each of which references buffers
+ * covering almost all of the aperture means that at each emit we end up
+ * waiting to evict a buffer from the last rendering, and we get synchronous
+ * performance. By emitting smaller batchbuffers, we eat some CPU overhead to
+ * get better parallelism.
*/
static int
dri_gem_check_aperture_space(dri_bo **bo_array, int count)
{
- return 0;
+ dri_bufmgr_gem *bufmgr_gem = (dri_bufmgr_gem *)bo_array[0]->bufmgr;
+ unsigned int total = 0;
+ unsigned int threshold = bufmgr_gem->gtt_size * 3 / 4;
+ int i;
+
+ for (i = 0; i < count; i++) {
+ dri_bo_gem *bo_gem = (dri_bo_gem *)bo_array[i];
+ if (bo_gem != NULL)
+ total += bo_gem->reloc_tree_size;
+ }
+
+ if (total > threshold) {
+ total = 0;
+ for (i = 0; i < count; i++)
+ total += dri_gem_bo_get_aperture_space(bo_array[i]);
+
+ for (i = 0; i < count; i++)
+ dri_gem_bo_clear_aperture_space_flag(bo_array[i]);
+ }
+
+ if (total > bufmgr_gem->gtt_size * 3 / 4) {
+ DBG("check_space: overflowed available aperture, %dkb vs %dkb\n",
+ total / 1024, (int)bufmgr_gem->gtt_size / 1024);
+ return -1;
+ } else {
+ DBG("drm_check_space: total %dkb vs bufgr %dkb\n", total / 1024 ,
+ (int)bufmgr_gem->gtt_size / 1024);
+ return 0;
+ }
}
/**
@@ -952,7 +1069,8 @@ dri_bufmgr *
intel_bufmgr_gem_init(int fd, int batch_size)
{
dri_bufmgr_gem *bufmgr_gem;
- int i;
+ struct drm_i915_gem_get_aperture aperture;
+ int ret, i;
bufmgr_gem = calloc(1, sizeof(*bufmgr_gem));
bufmgr_gem->fd = fd;
@@ -962,6 +1080,19 @@ intel_bufmgr_gem_init(int fd, int batch_size)
return NULL;
}
+ ret = ioctl(bufmgr_gem->fd, DRM_IOCTL_I915_GEM_GET_APERTURE, &aperture);
+
+ if (ret == 0)
+ bufmgr_gem->gtt_size = aperture.aper_available_size;
+ else {
+ fprintf(stderr, "DRM_IOCTL_I915_GEM_APERTURE failed: %s\n",
+ strerror(errno));
+ bufmgr_gem->gtt_size = 128 * 1024 * 1024;
+ fprintf(stderr, "Assuming %dkB available aperture size.\n"
+ "May lead to reduced performance or incorrect rendering.\n",
+ (int)bufmgr_gem->gtt_size / 1024);
+ }
+
/* Let's go with one relocation per every 2 dwords (but round down a bit
* since a power of two will mean an extra page allocation for the reloc
* buffer).