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i965: Drop the system-memory temporary allocations for flush explicit.

Browse source 
While in expected usage patterns nobody will ever hit this path, doubling
our bandwidth used seems like a waste, and it cost us extra code too.

Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
This commit is contained in:
Eric Anholt 2014-02-25 11:50:44 -08:00
parent ea93246c00
commit bb63df0c2d
2 changed files with 58 additions and 52 deletions
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103
src/mesa/drivers/dri/i965/intel_buffer_objects.c
View file

@ -409,27 +409,21 @@ intel_bufferobj_map_range(struct gl_context * ctx,
* guarantees the driver has advertised to the application.
*/
const unsigned alignment = ctx->Const.MinMapBufferAlignment;
const unsigned extra = (uintptr_t) offset % alignment;
if (access & GL_MAP_FLUSH_EXPLICIT_BIT) {
intel_obj->range_map_buffer[index] = _mesa_align_malloc(length + extra,
alignment);
obj->Mappings[index].Pointer =
intel_obj->range_map_buffer[index] + extra;
intel_obj->map_extra[index] = (uintptr_t) offset % alignment;
intel_obj->range_map_bo[index] = drm_intel_bo_alloc(brw->bufmgr,
"BO blit temp",
length +
intel_obj->map_extra[index],
alignment);
if (brw->has_llc) {
drm_intel_bo_map(intel_obj->range_map_bo[index],
(access & GL_MAP_WRITE_BIT) != 0);
} else {
intel_obj->range_map_bo[index] = drm_intel_bo_alloc(brw->bufmgr,
"range map",
length + extra,
alignment);
if (brw->has_llc) {
drm_intel_bo_map(intel_obj->range_map_bo[index],
(access & GL_MAP_WRITE_BIT) != 0);
} else {
drm_intel_gem_bo_map_gtt(intel_obj->range_map_bo[index]);
}
obj->Mappings[index].Pointer =
intel_obj->range_map_bo[index]->virtual + extra;
drm_intel_gem_bo_map_gtt(intel_obj->range_map_bo[index]);
}
obj->Mappings[index].Pointer =
intel_obj->range_map_bo[index]->virtual + intel_obj->map_extra[index];
return obj->Mappings[index].Pointer;
}
@ -468,35 +462,51 @@ intel_bufferobj_flush_mapped_range(struct gl_context *ctx,
{
struct brw_context *brw = brw_context(ctx);
struct intel_buffer_object *intel_obj = intel_buffer_object(obj);
drm_intel_bo *temp_bo;
GLbitfield access = obj->Mappings[index].AccessFlags;
/* Unless we're in the range map using a temporary system buffer,
* there's no work to do.
assert(access & GL_MAP_FLUSH_EXPLICIT_BIT);
/* If we gave a direct mapping of the buffer instead of using a temporary,
* then there's nothing to do.
*/
if (intel_obj->range_map_buffer[index] == NULL)
if (intel_obj->range_map_bo[index] == NULL)
return;
if (length == 0)
return;
temp_bo = drm_intel_bo_alloc(brw->bufmgr, "range map flush", length, 64);
/* Use obj->Pointer instead of intel_obj->range_map_buffer because the
* former points to the actual mapping while the latter may be offset to
* meet alignment guarantees.
/* Note that we're not unmapping our buffer while executing the blit. We
* need to have a mapping still at the end of this call, since the user
* gets to make further modifications and glFlushMappedBufferRange() calls.
* This is safe, because:
*
* - On LLC platforms, we're using a CPU mapping that's coherent with the
* GPU (except for the render caches), so the kernel doesn't need to do
* any flushing work for us except for what happens at batch exec time
* anyway.
*
* - On non-LLC platforms, we're using a GTT mapping that writes directly
* to system memory (except for the chipset cache that gets flushed at
* batch exec time).
*
* In both cases we don't need to stall for the previous blit to complete
* so we can re-map (and we definitely don't want to, since that would be
* slow): If the user edits a part of their buffer that's previously been
* blitted, then our lack of synchoronization is fine, because either
* they'll get some too-new data in the first blit and not do another blit
* of that area (but in that case the results are undefined), or they'll do
* another blit of that area and the complete newer data will land the
* second time.
*/
drm_intel_bo_subdata(temp_bo, 0, length, obj->Mappings[index].Pointer);
intel_emit_linear_blit(brw,
intel_obj->buffer,
obj->Mappings[index].Offset + offset,
temp_bo, 0,
intel_obj->range_map_bo[index],
intel_obj->map_extra[index] + offset,
length);
intel_bufferobj_mark_gpu_usage(intel_obj,
obj->Mappings[index].Offset + offset,
length);
drm_intel_bo_unreference(temp_bo);
}
@ -514,27 +524,18 @@ intel_bufferobj_unmap(struct gl_context * ctx, struct gl_buffer_object *obj,
assert(intel_obj);
assert(obj->Mappings[index].Pointer);
if (intel_obj->range_map_buffer[index] != NULL) {
/* Since we've emitted some blits to buffers that will (likely) be used
* in rendering operations in other cache domains in this batch, emit a
* flush. Once again, we wish for a domain tracker in libdrm to cover
* usage inside of a batchbuffer.
*/
intel_batchbuffer_emit_mi_flush(brw);
_mesa_align_free(intel_obj->range_map_buffer[index]);
intel_obj->range_map_buffer[index] = NULL;
} else if (intel_obj->range_map_bo[index] != NULL) {
const unsigned extra = obj->Mappings[index].Pointer -
intel_obj->range_map_bo[index]->virtual;
if (intel_obj->range_map_bo[index] != NULL) {
drm_intel_bo_unmap(intel_obj->range_map_bo[index]);
intel_emit_linear_blit(brw,
intel_obj->buffer, obj->Mappings[index].Offset,
intel_obj->range_map_bo[index], extra,
obj->Mappings[index].Length);
intel_bufferobj_mark_gpu_usage(intel_obj, obj->Mappings[index].Offset,
obj->Mappings[index].Length);
if (!(obj->Mappings[index].AccessFlags & GL_MAP_FLUSH_EXPLICIT_BIT)) {
intel_emit_linear_blit(brw,
intel_obj->buffer, obj->Mappings[index].Offset,
intel_obj->range_map_bo[index],
intel_obj->map_extra[index],
obj->Mappings[index].Length);
intel_bufferobj_mark_gpu_usage(intel_obj, obj->Mappings[index].Offset,
obj->Mappings[index].Length);
}
/* Since we've emitted some blits to buffers that will (likely) be used
* in rendering operations in other cache domains in this batch, emit a

7
src/mesa/drivers/dri/i965/intel_buffer_objects.h
View file

@ -43,7 +43,12 @@ struct intel_buffer_object
drm_intel_bo *buffer; /* the low-level buffer manager's buffer handle */
drm_intel_bo *range_map_bo[MAP_COUNT];
void *range_map_buffer[MAP_COUNT];
/**
* Alignment offset from the range_map_bo temporary mapping to the returned
* obj->Pointer (caused by GL_ARB_map_buffer_alignment).
*/
unsigned map_extra[MAP_COUNT];
/** @{
* Tracking for what range of the BO may currently be in use by the GPU.