/*
* Copyright © 2008 Intel Corporation
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the "Software"),
* to deal in the Software without restriction, including without limitation
* the rights to use, copy, modify, merge, publish, distribute, sublicense,
* and/or sell copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice (including the next
* paragraph) shall be included in all copies or substantial portions of the
* Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
* IN THE SOFTWARE.
*
* Authors:
* Eric Anholt <eric@anholt.net>
*
*/
/** @file brw_queryobj.c
*
* Support for query objects (GL_ARB_occlusion_query, GL_ARB_timer_query,
* GL_EXT_transform_feedback, and friends).
*
* The hardware provides a PIPE_CONTROL command that can report the number of
* fragments that passed the depth test, or the hardware timer. They are
* appropriately synced with the stage of the pipeline for our extensions'
* needs.
*/
#include "main/imports.h"
#include "brw_context.h"
#include "brw_defines.h"
#include "brw_state.h"
#include "intel_batchbuffer.h"
#include "intel_reg.h"
/**
* Emit PIPE_CONTROLs to write the current GPU timestamp into a buffer.
*/
void
brw_write_timestamp(struct brw_context *brw, drm_intel_bo *query_bo, int idx)
{
if (brw->gen == 6) {
/* Emit Sandybridge workaround flush: */
brw_emit_pipe_control_flush(brw,
PIPE_CONTROL_CS_STALL |
PIPE_CONTROL_STALL_AT_SCOREBOARD);
}
brw_emit_pipe_control_write(brw, PIPE_CONTROL_WRITE_TIMESTAMP,
query_bo, idx * sizeof(uint64_t), 0, 0);
}
/**
* Emit PIPE_CONTROLs to write the PS_DEPTH_COUNT register into a buffer.
*/
void
brw_write_depth_count(struct brw_context *brw, drm_intel_bo *query_bo, int idx)
{
uint32_t flags;
flags = (PIPE_CONTROL_WRITE_DEPTH_COUNT |
PIPE_CONTROL_DEPTH_STALL);
/* Needed to ensure the memory is coherent for the MI_LOAD_REGISTER_MEM
* command when loading the values into the predicate source registers for
* conditional rendering.
*/
if (brw->predicate.supported)
flags |= PIPE_CONTROL_FLUSH_ENABLE;
brw_emit_pipe_control_write(brw, flags, query_bo,
idx * sizeof(uint64_t), 0, 0);
}
/**
* Wait on the query object's BO and calculate the final result.
*/
static void
brw_queryobj_get_results(struct gl_context *ctx,
struct brw_query_object *query)
{
struct brw_context *brw = brw_context(ctx);
int i;
uint64_t *results;
if (query->bo == NULL)
return;
/* If the application has requested the query result, but this batch is
* still contributing to it, flush it now so the results will be present
* when mapped.
*/
if (drm_intel_bo_references(brw->batch.bo, query->bo))
intel_batchbuffer_flush(brw);
if (unlikely(brw->perf_debug)) {
if (drm_intel_bo_busy(query->bo)) {
perf_debug("Stalling on the GPU waiting for a query object.\n");
}
}
drm_intel_bo_map(query->bo, false);
results = query->bo->virtual;
switch (query->Base.Target) {
case GL_TIME_ELAPSED_EXT:
/* The query BO contains the starting and ending timestamps.
* Subtract the two and convert to nanoseconds.
*/
query->Base.Result += 1000 * ((results[1] >> 32) - (results[0] >> 32));
break;
case GL_TIMESTAMP:
/* The query BO contains a single timestamp value in results[0]. */
query->Base.Result = 1000 * (results[0] >> 32);
break;
case GL_SAMPLES_PASSED_ARB:
/* Loop over pairs of values from the BO, which are the PS_DEPTH_COUNT
* value at the start and end of the batchbuffer. Subtract them to
* get the number of fragments which passed the depth test in each
* individual batch, and add those differences up to get the number
* of fragments for the entire query.
*
* Note that query->Base.Result may already be non-zero. We may have
* run out of space in the query's BO and allocated a new one. If so,
* this function was already called to accumulate the results so far.
*/
for (i = 0; i < query->last_index; i++) {
query->Base.Result += results[i * 2 + 1] - results[i * 2];
}
break;
case GL_ANY_SAMPLES_PASSED:
case GL_ANY_SAMPLES_PASSED_CONSERVATIVE:
/* If the starting and ending PS_DEPTH_COUNT from any of the batches
* differ, then some fragments passed the depth test.
*/
for (i = 0; i < query->last_index; i++) {
if (results[i * 2 + 1] != results[i * 2]) {
query->Base.Result = GL_TRUE;
break;
}
}
break;
default:
unreachable("Unrecognized query target in brw_queryobj_get_results()");
}
drm_intel_bo_unmap(query->bo);
/* Now that we've processed the data stored in the query's buffer object,
* we can release it.
*/
drm_intel_bo_unreference(query->bo);
query->bo = NULL;
}
/**
* The NewQueryObject() driver hook.
*
* Allocates and initializes a new query object.
*/
static struct gl_query_object *
brw_new_query_object(struct gl_context *ctx, GLuint id)
{
struct brw_query_object *query;
query
= calloc(1, sizeof(struct brw_query_object
));
query->Base.Id = id;
query->Base.Result = 0;
query->Base.Active = false;
query->Base.Ready = true;
return &query->Base;
}
/**
* The DeleteQuery() driver hook.
*/
static void
brw_delete_query(struct gl_context *ctx, struct gl_query_object *q)
{
struct brw_query_object *query = (struct brw_query_object *)q;
drm_intel_bo_unreference(query->bo);
}
/**
* Gen4-5 driver hook for glBeginQuery().
*
* Initializes driver structures and emits any GPU commands required to begin
* recording data for the query.
*/
static void
brw_begin_query(struct gl_context *ctx, struct gl_query_object *q)
{
struct brw_context *brw = brw_context(ctx);
struct brw_query_object *query = (struct brw_query_object *)q;
switch (query->Base.Target) {
case GL_TIME_ELAPSED_EXT:
/* For timestamp queries, we record the starting time right away so that
* we measure the full time between BeginQuery and EndQuery. There's
* some debate about whether this is the right thing to do. Our decision
* is based on the following text from the ARB_timer_query extension:
*
* "(5) Should the extension measure total time elapsed between the full
* completion of the BeginQuery and EndQuery commands, or just time
* spent in the graphics library?
*
* RESOLVED: This extension will measure the total time elapsed
* between the full completion of these commands. Future extensions
* may implement a query to determine time elapsed at different stages
* of the graphics pipeline."
*
* We write a starting timestamp now (at index 0). At EndQuery() time,
* we'll write a second timestamp (at index 1), and subtract the two to
* obtain the time elapsed. Notably, this includes time elapsed while
* the system was doing other work, such as running other applications.
*/
drm_intel_bo_unreference(query->bo);
query->bo = drm_intel_bo_alloc(brw->bufmgr, "timer query", 4096, 4096);
brw_write_timestamp(brw, query->bo, 0);
break;
case GL_ANY_SAMPLES_PASSED:
case GL_ANY_SAMPLES_PASSED_CONSERVATIVE:
case GL_SAMPLES_PASSED_ARB:
/* For occlusion queries, we delay taking an initial sample until the
* first drawing occurs in this batch. See the reasoning in the comments
* for brw_emit_query_begin() below.
*
* Since we're starting a new query, we need to be sure to throw away
* any previous occlusion query results.
*/
drm_intel_bo_unreference(query->bo);
query->bo = NULL;
query->last_index = -1;
brw->query.obj = query;
/* Depth statistics on Gen4 require strange workarounds, so we try to
* avoid them when necessary. They're required for occlusion queries,
* so turn them on now.
*/
brw->stats_wm++;
brw->ctx.NewDriverState |= BRW_NEW_STATS_WM;
break;
default:
unreachable("Unrecognized query target in brw_begin_query()");
}
}
/**
* Gen4-5 driver hook for glEndQuery().
*
* Emits GPU commands to record a final query value, ending any data capturing.
* However, the final result isn't necessarily available until the GPU processes
* those commands. brw_queryobj_get_results() processes the captured data to
* produce the final result.
*/
static void
brw_end_query(struct gl_context *ctx, struct gl_query_object *q)
{
struct brw_context *brw = brw_context(ctx);
struct brw_query_object *query = (struct brw_query_object *)q;
switch (query->Base.Target) {
case GL_TIME_ELAPSED_EXT:
/* Write the final timestamp. */
brw_write_timestamp(brw, query->bo, 1);
break;
case GL_ANY_SAMPLES_PASSED:
case GL_ANY_SAMPLES_PASSED_CONSERVATIVE:
case GL_SAMPLES_PASSED_ARB:
/* No query->bo means that EndQuery was called after BeginQuery with no
* intervening drawing. Rather than doing nothing at all here in this
* case, we emit the query_begin and query_end state to the
* hardware. This is to guarantee that waiting on the result of this
* empty state will cause all previous queries to complete at all, as
* required by the specification:
*
* It must always be true that if any query object
* returns a result available of TRUE, all queries of the
* same type issued prior to that query must also return
* TRUE. [Open GL 4.3 (Core Profile) Section 4.2.1]
*/
if (!query->bo) {
brw_emit_query_begin(brw);
}
brw_emit_query_end(brw);
brw->query.obj = NULL;
brw->stats_wm--;
brw->ctx.NewDriverState |= BRW_NEW_STATS_WM;
break;
default:
unreachable("Unrecognized query target in brw_end_query()");
}
}
/**
* The Gen4-5 WaitQuery() driver hook.
*
* Wait for a query result to become available and return it. This is the
* backing for glGetQueryObjectiv() with the GL_QUERY_RESULT pname.
*/
static void brw_wait_query(struct gl_context *ctx, struct gl_query_object *q)
{
struct brw_query_object *query = (struct brw_query_object *)q;
assert(brw_context
(ctx
)->gen
< 6);
brw_queryobj_get_results(ctx, query);
query->Base.Ready = true;
}
/**
* The Gen4-5 CheckQuery() driver hook.
*
* Checks whether a query result is ready yet. If not, flushes.
* This is the backing for glGetQueryObjectiv()'s QUERY_RESULT_AVAILABLE pname.
*/
static void brw_check_query(struct gl_context *ctx, struct gl_query_object *q)
{
struct brw_context *brw = brw_context(ctx);
struct brw_query_object *query = (struct brw_query_object *)q;
/* From the GL_ARB_occlusion_query spec:
*
* "Instead of allowing for an infinite loop, performing a
* QUERY_RESULT_AVAILABLE_ARB will perform a flush if the result is
* not ready yet on the first time it is queried. This ensures that
* the async query will return true in finite time.
*/
if (query->bo && drm_intel_bo_references(brw->batch.bo, query->bo))
intel_batchbuffer_flush(brw);
if (query->bo == NULL || !drm_intel_bo_busy(query->bo)) {
brw_queryobj_get_results(ctx, query);
query->Base.Ready = true;
}
}
/**
* Ensure there query's BO has enough space to store a new pair of values.
*
* If not, gather the existing BO's results and create a new buffer of the
* same size.
*/
static void
ensure_bo_has_space(struct gl_context *ctx, struct brw_query_object *query)
{
struct brw_context *brw = brw_context(ctx);
if (!query->bo || query->last_index * 2 + 1 >= 4096 / sizeof(uint64_t)) {
if (query->bo != NULL) {
/* The old query BO did not have enough space, so we allocated a new
* one. Gather the results so far (adding up the differences) and
* release the old BO.
*/
brw_queryobj_get_results(ctx, query);
}
query->bo = drm_intel_bo_alloc(brw->bufmgr, "query", 4096, 1);
query->last_index = 0;
}
}
/**
* Record the PS_DEPTH_COUNT value (for occlusion queries) just before
* primitive drawing.
*
* In a pre-hardware context world, the single PS_DEPTH_COUNT register is
* shared among all applications using the GPU. However, our query value
* needs to only include fragments generated by our application/GL context.
*
* To accommodate this, we record PS_DEPTH_COUNT at the start and end of
* each batchbuffer (technically, the first primitive drawn and flush time).
* Subtracting each pair of values calculates the change in PS_DEPTH_COUNT
* caused by a batchbuffer. Since there is no preemption inside batches,
* this is guaranteed to only measure the effects of our current application.
*
* Adding each of these differences (in case drawing is done over many batches)
* produces the final expected value.
*
* In a world with hardware contexts, PS_DEPTH_COUNT is saved and restored
* as part of the context state, so this is unnecessary, and skipped.
*/
void
brw_emit_query_begin(struct brw_context *brw)
{
struct gl_context *ctx = &brw->ctx;
struct brw_query_object *query = brw->query.obj;
if (brw->hw_ctx)
return;
/* Skip if we're not doing any queries, or we've already recorded the
* initial query value for this batchbuffer.
*/
if (!query || brw->query.begin_emitted)
return;
ensure_bo_has_space(ctx, query);
brw_write_depth_count(brw, query->bo, query->last_index * 2);
brw->query.begin_emitted = true;
}
/**
* Called at batchbuffer flush to get an ending PS_DEPTH_COUNT
* (for non-hardware context platforms).
*
* See the explanation in brw_emit_query_begin().
*/
void
brw_emit_query_end(struct brw_context *brw)
{
struct brw_query_object *query = brw->query.obj;
if (brw->hw_ctx)
return;
if (!brw->query.begin_emitted)
return;
brw_write_depth_count(brw, query->bo, query->last_index * 2 + 1);
brw->query.begin_emitted = false;
query->last_index++;
}
/**
* Driver hook for glQueryCounter().
*
* This handles GL_TIMESTAMP queries, which perform a pipelined read of the
* current GPU time. This is unlike GL_TIME_ELAPSED, which measures the
* time while the query is active.
*/
static void
brw_query_counter(struct gl_context *ctx, struct gl_query_object *q)
{
struct brw_context *brw = brw_context(ctx);
struct brw_query_object *query = (struct brw_query_object *) q;
assert(q
->Target
== GL_TIMESTAMP
);
drm_intel_bo_unreference(query->bo);
query->bo = drm_intel_bo_alloc(brw->bufmgr, "timestamp query", 4096, 4096);
brw_write_timestamp(brw, query->bo, 0);
query->flushed = false;
}
/**
* Read the TIMESTAMP register immediately (in a non-pipelined fashion).
*
* This is used to implement the GetTimestamp() driver hook.
*/
static uint64_t
brw_get_timestamp(struct gl_context *ctx)
{
struct brw_context *brw = brw_context(ctx);
uint64_t result = 0;
drm_intel_reg_read(brw->bufmgr, TIMESTAMP, &result);
/* See logic in brw_queryobj_get_results() */
result = result >> 32;
result *= 80;
result &= (1ull << 36) - 1;
return result;
}
/* Initialize query object functions used on all generations. */
void brw_init_common_queryobj_functions(struct dd_function_table *functions)
{
functions->NewQueryObject = brw_new_query_object;
functions->DeleteQuery = brw_delete_query;
functions->QueryCounter = brw_query_counter;
functions->GetTimestamp = brw_get_timestamp;
}
/* Initialize Gen4/5-specific query object functions. */
void gen4_init_queryobj_functions(struct dd_function_table *functions)
{
functions->BeginQuery = brw_begin_query;
functions->EndQuery = brw_end_query;
functions->CheckQuery = brw_check_query;
functions->WaitQuery = brw_wait_query;
}