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/*

 * 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 

 *

 */

/** @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;

   assert(brw->gen < 6);

   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);

   free(query);

}

/**

 * 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;

   assert(brw->gen < 6);

   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;

   assert(brw->gen < 6);

   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);

      }

      assert(query->bo);

      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;

   assert(brw->gen < 6);

   /* 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);

   assert(brw->gen < 6);

   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;

}