src/mesa/drivers/dri/i965/brw_queryobj.c

   1 /*
   2  * Copyright © 2008 Intel Corporation
   3  *
   4  * Permission is hereby granted, free of charge, to any person obtaining a
   5  * copy of this software and associated documentation files (the "Software"),
   6  * to deal in the Software without restriction, including without limitation
   7  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
   8  * and/or sell copies of the Software, and to permit persons to whom the
   9  * Software is furnished to do so, subject to the following conditions:
  10  *
  11  * The above copyright notice and this permission notice (including the next
  12  * paragraph) shall be included in all copies or substantial portions of the
  13  * Software.
  14  *
  15  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  16  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  17  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  18  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  19  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  20  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
  21  * IN THE SOFTWARE.
  22  *
  23  * Authors:
  24  *    Eric Anholt <eric@anholt.net>
  25  *
  26  */
  27
  28 /** @file brw_queryobj.c
  29  *
  30  * Support for query objects (GL_ARB_occlusion_query, GL_ARB_timer_query,
  31  * GL_EXT_transform_feedback, and friends).
  32  *
  33  * The hardware provides a PIPE_CONTROL command that can report the number of
  34  * fragments that passed the depth test, or the hardware timer.  They are
  35  * appropriately synced with the stage of the pipeline for our extensions'
  36  * needs.
  37  */
  38 #include "main/imports.h"
  39
  40 #include "brw_context.h"
  41 #include "brw_defines.h"
  42 #include "brw_state.h"
  43 #include "intel_batchbuffer.h"
  44
  45 /**
  46  * Emit PIPE_CONTROLs to write the current GPU timestamp into a buffer.
  47  */
  48 void
  49 brw_write_timestamp(struct brw_context *brw, drm_intel_bo *query_bo, int idx)
  50 {
  51    if (brw->gen == 6) {
  52       /* Emit Sandybridge workaround flush: */
  53       brw_emit_pipe_control_flush(brw,
  54                                   PIPE_CONTROL_CS_STALL |
  55                                   PIPE_CONTROL_STALL_AT_SCOREBOARD);
  56    }
  57
  58    uint32_t flags = PIPE_CONTROL_WRITE_TIMESTAMP;
  59
  60    if (brw->gen == 9 && brw->gt == 4)
  61       flags |= PIPE_CONTROL_CS_STALL;
  62
  63    brw_emit_pipe_control_write(brw, flags,
  64                                query_bo, idx * sizeof(uint64_t), 0, 0);
  65 }
  66
  67 /**
  68  * Emit PIPE_CONTROLs to write the PS_DEPTH_COUNT register into a buffer.
  69  */
  70 void
  71 brw_write_depth_count(struct brw_context *brw, drm_intel_bo *query_bo, int idx)
  72 {
  73    uint32_t flags = PIPE_CONTROL_WRITE_DEPTH_COUNT | PIPE_CONTROL_DEPTH_STALL;
  74
  75    if (brw->gen == 9 && brw->gt == 4)
  76       flags |= PIPE_CONTROL_CS_STALL;
  77
  78    brw_emit_pipe_control_write(brw, flags,
  79                                query_bo, idx * sizeof(uint64_t),
  80                                0, 0);
  81 }
  82
  83 /**
  84  * Wait on the query object's BO and calculate the final result.
  85  */
  86 static void
  87 brw_queryobj_get_results(struct gl_context *ctx,
  88                          struct brw_query_object *query)
  89 {
  90    struct brw_context *brw = brw_context(ctx);
  91
  92    int i;
  93    uint64_t *results;
  94
  95    assert(brw->gen < 6);
  96
  97    if (query->bo == NULL)
  98       return;
  99
 100    /* If the application has requested the query result, but this batch is
 101     * still contributing to it, flush it now so the results will be present
 102     * when mapped.
 103     */
 104    if (drm_intel_bo_references(brw->batch.bo, query->bo))
 105       intel_batchbuffer_flush(brw);
 106
 107    if (unlikely(brw->perf_debug)) {
 108       if (drm_intel_bo_busy(query->bo)) {
 109          perf_debug("Stalling on the GPU waiting for a query object.\n");
 110       }
 111    }
 112
 113    drm_intel_bo_map(query->bo, false);
 114    results = query->bo->virtual;
 115    switch (query->Base.Target) {
 116    case GL_TIME_ELAPSED_EXT:
 117       /* The query BO contains the starting and ending timestamps.
 118        * Subtract the two and convert to nanoseconds.
 119        */
 120       query->Base.Result += 1000 * ((results[1] >> 32) - (results[0] >> 32));
 121       break;
 122
 123    case GL_TIMESTAMP:
 124       /* The query BO contains a single timestamp value in results[0]. */
 125       query->Base.Result = 1000 * (results[0] >> 32);
 126       break;
 127
 128    case GL_SAMPLES_PASSED_ARB:
 129       /* Loop over pairs of values from the BO, which are the PS_DEPTH_COUNT
 130        * value at the start and end of the batchbuffer.  Subtract them to
 131        * get the number of fragments which passed the depth test in each
 132        * individual batch, and add those differences up to get the number
 133        * of fragments for the entire query.
 134        *
 135        * Note that query->Base.Result may already be non-zero.  We may have
 136        * run out of space in the query's BO and allocated a new one.  If so,
 137        * this function was already called to accumulate the results so far.
 138        */
 139       for (i = 0; i < query->last_index; i++) {
 140          query->Base.Result += results[i * 2 + 1] - results[i * 2];
 141       }
 142       break;
 143
 144    case GL_ANY_SAMPLES_PASSED:
 145    case GL_ANY_SAMPLES_PASSED_CONSERVATIVE:
 146       /* If the starting and ending PS_DEPTH_COUNT from any of the batches
 147        * differ, then some fragments passed the depth test.
 148        */
 149       for (i = 0; i < query->last_index; i++) {
 150          if (results[i * 2 + 1] != results[i * 2]) {
 151             query->Base.Result = GL_TRUE;
 152             break;
 153          }
 154       }
 155       break;
 156
 157    default:
 158       unreachable("Unrecognized query target in brw_queryobj_get_results()");
 159    }
 160    drm_intel_bo_unmap(query->bo);
 161
 162    /* Now that we've processed the data stored in the query's buffer object,
 163     * we can release it.
 164     */
 165    drm_intel_bo_unreference(query->bo);
 166    query->bo = NULL;
 167 }
 168
 169 /**
 170  * The NewQueryObject() driver hook.
 171  *
 172  * Allocates and initializes a new query object.
 173  */
 174 static struct gl_query_object *
 175 brw_new_query_object(struct gl_context *ctx, GLuint id)
 176 {
 177    struct brw_query_object *query;
 178
 179    query = calloc(1, sizeof(struct brw_query_object));
 180
 181    query->Base.Id = id;
 182    query->Base.Result = 0;
 183    query->Base.Active = false;
 184    query->Base.Ready = true;
 185
 186    return &query->Base;
 187 }
 188
 189 /**
 190  * The DeleteQuery() driver hook.
 191  */
 192 static void
 193 brw_delete_query(struct gl_context *ctx, struct gl_query_object *q)
 194 {
 195    struct brw_query_object *query = (struct brw_query_object *)q;
 196
 197    drm_intel_bo_unreference(query->bo);
 198    free(query);
 199 }
 200
 201 /**
 202  * Gen4-5 driver hook for glBeginQuery().
 203  *
 204  * Initializes driver structures and emits any GPU commands required to begin
 205  * recording data for the query.
 206  */
 207 static void
 208 brw_begin_query(struct gl_context *ctx, struct gl_query_object *q)
 209 {
 210    struct brw_context *brw = brw_context(ctx);
 211    struct brw_query_object *query = (struct brw_query_object *)q;
 212
 213    assert(brw->gen < 6);
 214
 215    switch (query->Base.Target) {
 216    case GL_TIME_ELAPSED_EXT:
 217       /* For timestamp queries, we record the starting time right away so that
 218        * we measure the full time between BeginQuery and EndQuery.  There's
 219        * some debate about whether this is the right thing to do.  Our decision
 220        * is based on the following text from the ARB_timer_query extension:
 221        *
 222        * "(5) Should the extension measure total time elapsed between the full
 223        *      completion of the BeginQuery and EndQuery commands, or just time
 224        *      spent in the graphics library?
 225        *
 226        *  RESOLVED:  This extension will measure the total time elapsed
 227        *  between the full completion of these commands.  Future extensions
 228        *  may implement a query to determine time elapsed at different stages
 229        *  of the graphics pipeline."
 230        *
 231        * We write a starting timestamp now (at index 0).  At EndQuery() time,
 232        * we'll write a second timestamp (at index 1), and subtract the two to
 233        * obtain the time elapsed.  Notably, this includes time elapsed while
 234        * the system was doing other work, such as running other applications.
 235        */
 236       drm_intel_bo_unreference(query->bo);
 237       query->bo = drm_intel_bo_alloc(brw->bufmgr, "timer query", 4096, 4096);
 238       brw_write_timestamp(brw, query->bo, 0);
 239       break;
 240
 241    case GL_ANY_SAMPLES_PASSED:
 242    case GL_ANY_SAMPLES_PASSED_CONSERVATIVE:
 243    case GL_SAMPLES_PASSED_ARB:
 244       /* For occlusion queries, we delay taking an initial sample until the
 245        * first drawing occurs in this batch.  See the reasoning in the comments
 246        * for brw_emit_query_begin() below.
 247        *
 248        * Since we're starting a new query, we need to be sure to throw away
 249        * any previous occlusion query results.
 250        */
 251       drm_intel_bo_unreference(query->bo);
 252       query->bo = NULL;
 253       query->last_index = -1;
 254
 255       brw->query.obj = query;
 256
 257       /* Depth statistics on Gen4 require strange workarounds, so we try to
 258        * avoid them when necessary.  They're required for occlusion queries,
 259        * so turn them on now.
 260        */
 261       brw->stats_wm++;
 262       brw->ctx.NewDriverState |= BRW_NEW_STATS_WM;
 263       break;
 264
 265    default:
 266       unreachable("Unrecognized query target in brw_begin_query()");
 267    }
 268 }
 269
 270 /**
 271  * Gen4-5 driver hook for glEndQuery().
 272  *
 273  * Emits GPU commands to record a final query value, ending any data capturing.
 274  * However, the final result isn't necessarily available until the GPU processes
 275  * those commands.  brw_queryobj_get_results() processes the captured data to
 276  * produce the final result.
 277  */
 278 static void
 279 brw_end_query(struct gl_context *ctx, struct gl_query_object *q)
 280 {
 281    struct brw_context *brw = brw_context(ctx);
 282    struct brw_query_object *query = (struct brw_query_object *)q;
 283
 284    assert(brw->gen < 6);
 285
 286    switch (query->Base.Target) {
 287    case GL_TIME_ELAPSED_EXT:
 288       /* Write the final timestamp. */
 289       brw_write_timestamp(brw, query->bo, 1);
 290       break;
 291
 292    case GL_ANY_SAMPLES_PASSED:
 293    case GL_ANY_SAMPLES_PASSED_CONSERVATIVE:
 294    case GL_SAMPLES_PASSED_ARB:
 295
 296       /* No query->bo means that EndQuery was called after BeginQuery with no
 297        * intervening drawing. Rather than doing nothing at all here in this
 298        * case, we emit the query_begin and query_end state to the
 299        * hardware. This is to guarantee that waiting on the result of this
 300        * empty state will cause all previous queries to complete at all, as
 301        * required by the specification:
 302        *
 303        *        It must always be true that if any query object
 304        *        returns a result available of TRUE, all queries of the
 305        *        same type issued prior to that query must also return
 306        *        TRUE. [Open GL 4.3 (Core Profile) Section 4.2.1]
 307        */
 308       if (!query->bo) {
 309          brw_emit_query_begin(brw);
 310       }
 311
 312       assert(query->bo);
 313
 314       brw_emit_query_end(brw);
 315
 316       brw->query.obj = NULL;
 317
 318       brw->stats_wm--;
 319       brw->ctx.NewDriverState |= BRW_NEW_STATS_WM;
 320       break;
 321
 322    default:
 323       unreachable("Unrecognized query target in brw_end_query()");
 324    }
 325 }
 326
 327 /**
 328  * The Gen4-5 WaitQuery() driver hook.
 329  *
 330  * Wait for a query result to become available and return it.  This is the
 331  * backing for glGetQueryObjectiv() with the GL_QUERY_RESULT pname.
 332  */
 333 static void brw_wait_query(struct gl_context *ctx, struct gl_query_object *q)
 334 {
 335    struct brw_query_object *query = (struct brw_query_object *)q;
 336
 337    assert(brw_context(ctx)->gen < 6);
 338
 339    brw_queryobj_get_results(ctx, query);
 340    query->Base.Ready = true;
 341 }
 342
 343 /**
 344  * The Gen4-5 CheckQuery() driver hook.
 345  *
 346  * Checks whether a query result is ready yet.  If not, flushes.
 347  * This is the backing for glGetQueryObjectiv()'s QUERY_RESULT_AVAILABLE pname.
 348  */
 349 static void brw_check_query(struct gl_context *ctx, struct gl_query_object *q)
 350 {
 351    struct brw_context *brw = brw_context(ctx);
 352    struct brw_query_object *query = (struct brw_query_object *)q;
 353
 354    assert(brw->gen < 6);
 355
 356    /* From the GL_ARB_occlusion_query spec:
 357     *
 358     *     "Instead of allowing for an infinite loop, performing a
 359     *      QUERY_RESULT_AVAILABLE_ARB will perform a flush if the result is
 360     *      not ready yet on the first time it is queried.  This ensures that
 361     *      the async query will return true in finite time.
 362     */
 363    if (query->bo && drm_intel_bo_references(brw->batch.bo, query->bo))
 364       intel_batchbuffer_flush(brw);
 365
 366    if (query->bo == NULL || !drm_intel_bo_busy(query->bo)) {
 367       brw_queryobj_get_results(ctx, query);
 368       query->Base.Ready = true;
 369    }
 370 }
 371
 372 /**
 373  * Ensure there query's BO has enough space to store a new pair of values.
 374  *
 375  * If not, gather the existing BO's results and create a new buffer of the
 376  * same size.
 377  */
 378 static void
 379 ensure_bo_has_space(struct gl_context *ctx, struct brw_query_object *query)
 380 {
 381    struct brw_context *brw = brw_context(ctx);
 382
 383    assert(brw->gen < 6);
 384
 385    if (!query->bo || query->last_index * 2 + 1 >= 4096 / sizeof(uint64_t)) {
 386
 387       if (query->bo != NULL) {
 388          /* The old query BO did not have enough space, so we allocated a new
 389           * one.  Gather the results so far (adding up the differences) and
 390           * release the old BO.
 391           */
 392          brw_queryobj_get_results(ctx, query);
 393       }
 394
 395       query->bo = drm_intel_bo_alloc(brw->bufmgr, "query", 4096, 1);
 396       query->last_index = 0;
 397    }
 398 }
 399
 400 /**
 401  * Record the PS_DEPTH_COUNT value (for occlusion queries) just before
 402  * primitive drawing.
 403  *
 404  * In a pre-hardware context world, the single PS_DEPTH_COUNT register is
 405  * shared among all applications using the GPU.  However, our query value
 406  * needs to only include fragments generated by our application/GL context.
 407  *
 408  * To accommodate this, we record PS_DEPTH_COUNT at the start and end of
 409  * each batchbuffer (technically, the first primitive drawn and flush time).
 410  * Subtracting each pair of values calculates the change in PS_DEPTH_COUNT
 411  * caused by a batchbuffer.  Since there is no preemption inside batches,
 412  * this is guaranteed to only measure the effects of our current application.
 413  *
 414  * Adding each of these differences (in case drawing is done over many batches)
 415  * produces the final expected value.
 416  *
 417  * In a world with hardware contexts, PS_DEPTH_COUNT is saved and restored
 418  * as part of the context state, so this is unnecessary, and skipped.
 419  */
 420 void
 421 brw_emit_query_begin(struct brw_context *brw)
 422 {
 423    struct gl_context *ctx = &brw->ctx;
 424    struct brw_query_object *query = brw->query.obj;
 425
 426    if (brw->hw_ctx)
 427       return;
 428
 429    /* Skip if we're not doing any queries, or we've already recorded the
 430     * initial query value for this batchbuffer.
 431     */
 432    if (!query || brw->query.begin_emitted)
 433       return;
 434
 435    ensure_bo_has_space(ctx, query);
 436
 437    brw_write_depth_count(brw, query->bo, query->last_index * 2);
 438
 439    brw->query.begin_emitted = true;
 440 }
 441
 442 /**
 443  * Called at batchbuffer flush to get an ending PS_DEPTH_COUNT
 444  * (for non-hardware context platforms).
 445  *
 446  * See the explanation in brw_emit_query_begin().
 447  */
 448 void
 449 brw_emit_query_end(struct brw_context *brw)
 450 {
 451    struct brw_query_object *query = brw->query.obj;
 452
 453    if (brw->hw_ctx)
 454       return;
 455
 456    if (!brw->query.begin_emitted)
 457       return;
 458
 459    brw_write_depth_count(brw, query->bo, query->last_index * 2 + 1);
 460
 461    brw->query.begin_emitted = false;
 462    query->last_index++;
 463 }
 464
 465 /**
 466  * Driver hook for glQueryCounter().
 467  *
 468  * This handles GL_TIMESTAMP queries, which perform a pipelined read of the
 469  * current GPU time.  This is unlike GL_TIME_ELAPSED, which measures the
 470  * time while the query is active.
 471  */
 472 void
 473 brw_query_counter(struct gl_context *ctx, struct gl_query_object *q)
 474 {
 475    struct brw_context *brw = brw_context(ctx);
 476    struct brw_query_object *query = (struct brw_query_object *) q;
 477
 478    assert(q->Target == GL_TIMESTAMP);
 479
 480    drm_intel_bo_unreference(query->bo);
 481    query->bo = drm_intel_bo_alloc(brw->bufmgr, "timestamp query", 4096, 4096);
 482    brw_write_timestamp(brw, query->bo, 0);
 483
 484    query->flushed = false;
 485 }
 486
 487 /**
 488  * Read the TIMESTAMP register immediately (in a non-pipelined fashion).
 489  *
 490  * This is used to implement the GetTimestamp() driver hook.
 491  */
 492 static uint64_t
 493 brw_get_timestamp(struct gl_context *ctx)
 494 {
 495    struct brw_context *brw = brw_context(ctx);
 496    uint64_t result = 0;
 497
 498    switch (brw->screen->hw_has_timestamp) {
 499    case 3: /* New kernel, always full 36bit accuracy */
 500       drm_intel_reg_read(brw->bufmgr, TIMESTAMP | 1, &result);
 501       break;
 502    case 2: /* 64bit kernel, result is left-shifted by 32bits, losing 4bits */
 503       drm_intel_reg_read(brw->bufmgr, TIMESTAMP, &result);
 504       result = result >> 32;
 505       break;
 506    case 1: /* 32bit kernel, result is 36bit wide but may be inaccurate! */
 507       drm_intel_reg_read(brw->bufmgr, TIMESTAMP, &result);
 508       break;
 509    }
 510
 511    /* See logic in brw_queryobj_get_results() */
 512    result *= 80;
 513    result &= (1ull << 36) - 1;
 514    return result;
 515 }
 516
 517 /**
 518  * Is this type of query written by PIPE_CONTROL?
 519  */
 520 bool
 521 brw_is_query_pipelined(struct brw_query_object *query)
 522 {
 523    switch (query->Base.Target) {
 524    case GL_TIMESTAMP:
 525    case GL_TIME_ELAPSED:
 526    case GL_ANY_SAMPLES_PASSED:
 527    case GL_ANY_SAMPLES_PASSED_CONSERVATIVE:
 528    case GL_SAMPLES_PASSED_ARB:
 529       return true;
 530
 531    case GL_PRIMITIVES_GENERATED:
 532    case GL_TRANSFORM_FEEDBACK_PRIMITIVES_WRITTEN:
 533    case GL_VERTICES_SUBMITTED_ARB:
 534    case GL_PRIMITIVES_SUBMITTED_ARB:
 535    case GL_VERTEX_SHADER_INVOCATIONS_ARB:
 536    case GL_GEOMETRY_SHADER_INVOCATIONS:
 537    case GL_GEOMETRY_SHADER_PRIMITIVES_EMITTED_ARB:
 538    case GL_FRAGMENT_SHADER_INVOCATIONS_ARB:
 539    case GL_CLIPPING_INPUT_PRIMITIVES_ARB:
 540    case GL_CLIPPING_OUTPUT_PRIMITIVES_ARB:
 541    case GL_COMPUTE_SHADER_INVOCATIONS_ARB:
 542    case GL_TESS_CONTROL_SHADER_PATCHES_ARB:
 543    case GL_TESS_EVALUATION_SHADER_INVOCATIONS_ARB:
 544       return false;
 545
 546    default:
 547       unreachable("Unrecognized query target in is_query_pipelined()");
 548    }
 549 }
 550
 551 /* Initialize query object functions used on all generations. */
 552 void brw_init_common_queryobj_functions(struct dd_function_table *functions)
 553 {
 554    functions->NewQueryObject = brw_new_query_object;
 555    functions->DeleteQuery = brw_delete_query;
 556    functions->GetTimestamp = brw_get_timestamp;
 557 }
 558
 559 /* Initialize Gen4/5-specific query object functions. */
 560 void gen4_init_queryobj_functions(struct dd_function_table *functions)
 561 {
 562    functions->BeginQuery = brw_begin_query;
 563    functions->EndQuery = brw_end_query;
 564    functions->CheckQuery = brw_check_query;
 565    functions->WaitQuery = brw_wait_query;
 566    functions->QueryCounter = brw_query_counter;
 567 }