src/mesa/drivers/dri/i965/gen6_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  *    Kenneth Graunke <kenneth@whitecape.org>
  26  */
  27
  28 /** @file gen6_queryobj.c
  29  *
  30  * Support for query objects (GL_ARB_occlusion_query, GL_ARB_timer_query,
  31  * GL_EXT_transform_feedback, and friends) on platforms that support
  32  * hardware contexts (Gen6+).
  33  */
  34 #include "main/imports.h"
  35
  36 #include "brw_context.h"
  37 #include "brw_defines.h"
  38 #include "brw_state.h"
  39 #include "intel_batchbuffer.h"
  40 #include "intel_reg.h"
  41
  42 /**
  43  * Emit PIPE_CONTROLs to write the current GPU timestamp into a buffer.
  44  */
  45 static void
  46 write_timestamp(struct brw_context *brw, drm_intel_bo *query_bo, int idx)
  47 {
  48    /* Emit workaround flushes: */
  49    if (brw->gen == 6) {
  50       /* The timestamp write below is a non-zero post-sync op, which on
  51        * Gen6 necessitates a CS stall.  CS stalls need stall at scoreboard
  52        * set.  See the comments for intel_emit_post_sync_nonzero_flush().
  53        */
  54       BEGIN_BATCH(4);
  55       OUT_BATCH(_3DSTATE_PIPE_CONTROL | (4 - 2));
  56       OUT_BATCH(PIPE_CONTROL_CS_STALL | PIPE_CONTROL_STALL_AT_SCOREBOARD);
  57       OUT_BATCH(0);
  58       OUT_BATCH(0);
  59       ADVANCE_BATCH();
  60    }
  61
  62    BEGIN_BATCH(5);
  63    OUT_BATCH(_3DSTATE_PIPE_CONTROL | (5 - 2));
  64    OUT_BATCH(PIPE_CONTROL_WRITE_TIMESTAMP);
  65    OUT_RELOC(query_bo,
  66              I915_GEM_DOMAIN_INSTRUCTION, I915_GEM_DOMAIN_INSTRUCTION,
  67              PIPE_CONTROL_GLOBAL_GTT_WRITE |
  68              idx * sizeof(uint64_t));
  69    OUT_BATCH(0);
  70    OUT_BATCH(0);
  71    ADVANCE_BATCH();
  72 }
  73
  74 /**
  75  * Emit PIPE_CONTROLs to write the PS_DEPTH_COUNT register into a buffer.
  76  */
  77 static void
  78 write_depth_count(struct brw_context *brw, drm_intel_bo *query_bo, int idx)
  79 {
  80    /* Emit Sandybridge workaround flush: */
  81    if (brw->gen == 6)
  82       intel_emit_post_sync_nonzero_flush(brw);
  83
  84    BEGIN_BATCH(5);
  85    OUT_BATCH(_3DSTATE_PIPE_CONTROL | (5 - 2));
  86    OUT_BATCH(PIPE_CONTROL_DEPTH_STALL |
  87              PIPE_CONTROL_WRITE_DEPTH_COUNT);
  88    OUT_RELOC(query_bo,
  89              I915_GEM_DOMAIN_INSTRUCTION, I915_GEM_DOMAIN_INSTRUCTION,
  90              PIPE_CONTROL_GLOBAL_GTT_WRITE |
  91              (idx * sizeof(uint64_t)));
  92    OUT_BATCH(0);
  93    OUT_BATCH(0);
  94    ADVANCE_BATCH();
  95 }
  96
  97 /*
  98  * Write an arbitrary 64-bit register to a buffer via MI_STORE_REGISTER_MEM.
  99  *
 100  * Only TIMESTAMP and PS_DEPTH_COUNT have special PIPE_CONTROL support; other
 101  * counters have to be read via the generic MI_STORE_REGISTER_MEM.
 102  *
 103  * Callers must explicitly flush the pipeline to ensure the desired value is
 104  * available.
 105  */
 106 void
 107 brw_store_register_mem64(struct brw_context *brw,
 108                          drm_intel_bo *bo, uint32_t reg, int idx)
 109 {
 110    assert(brw->gen >= 6);
 111
 112    /* MI_STORE_REGISTER_MEM only stores a single 32-bit value, so to
 113     * read a full 64-bit register, we need to do two of them.
 114     */
 115    BEGIN_BATCH(3);
 116    OUT_BATCH(MI_STORE_REGISTER_MEM | (3 - 2));
 117    OUT_BATCH(reg);
 118    OUT_RELOC(bo, I915_GEM_DOMAIN_RENDER, I915_GEM_DOMAIN_RENDER,
 119              idx * sizeof(uint64_t));
 120    ADVANCE_BATCH();
 121
 122    BEGIN_BATCH(3);
 123    OUT_BATCH(MI_STORE_REGISTER_MEM | (3 - 2));
 124    OUT_BATCH(reg + sizeof(uint32_t));
 125    OUT_RELOC(bo, I915_GEM_DOMAIN_RENDER, I915_GEM_DOMAIN_RENDER,
 126              sizeof(uint32_t) + idx * sizeof(uint64_t));
 127    ADVANCE_BATCH();
 128 }
 129
 130 static void
 131 write_primitives_generated(struct brw_context *brw,
 132                            drm_intel_bo *query_bo, int idx)
 133 {
 134    intel_batchbuffer_emit_mi_flush(brw);
 135
 136    brw_store_register_mem64(brw, query_bo, CL_INVOCATION_COUNT, idx);
 137 }
 138
 139 static void
 140 write_xfb_primitives_written(struct brw_context *brw,
 141                              drm_intel_bo *bo, int idx)
 142 {
 143    intel_batchbuffer_emit_mi_flush(brw);
 144
 145    if (brw->gen >= 7) {
 146       brw_store_register_mem64(brw, bo, GEN7_SO_NUM_PRIMS_WRITTEN(0), idx);
 147    } else {
 148       brw_store_register_mem64(brw, bo, GEN6_SO_NUM_PRIMS_WRITTEN, idx);
 149    }
 150 }
 151
 152 /**
 153  * Wait on the query object's BO and calculate the final result.
 154  */
 155 static void
 156 gen6_queryobj_get_results(struct gl_context *ctx,
 157                           struct brw_query_object *query)
 158 {
 159    struct brw_context *brw = brw_context(ctx);
 160
 161    if (query->bo == NULL)
 162       return;
 163
 164    /* If the application has requested the query result, but this batch is
 165     * still contributing to it, flush it now so the results will be present
 166     * when mapped.
 167     */
 168    if (drm_intel_bo_references(brw->batch.bo, query->bo))
 169       intel_batchbuffer_flush(brw);
 170
 171    if (unlikely(brw->perf_debug)) {
 172       if (drm_intel_bo_busy(query->bo)) {
 173          perf_debug("Stalling on the GPU waiting for a query object.\n");
 174       }
 175    }
 176
 177    drm_intel_bo_map(query->bo, false);
 178    uint64_t *results = query->bo->virtual;
 179    switch (query->Base.Target) {
 180    case GL_TIME_ELAPSED:
 181       /* The query BO contains the starting and ending timestamps.
 182        * Subtract the two and convert to nanoseconds.
 183        */
 184       query->Base.Result += 80 * (results[1] - results[0]);
 185       break;
 186
 187    case GL_TIMESTAMP:
 188       /* Our timer is a clock that increments every 80ns (regardless of
 189        * other clock scaling in the system).  The timestamp register we can
 190        * read for glGetTimestamp() masks out the top 32 bits, so we do that
 191        * here too to let the two counters be compared against each other.
 192        *
 193        * If we just multiplied that 32 bits of data by 80, it would roll
 194        * over at a non-power-of-two, so an application couldn't use
 195        * GL_QUERY_COUNTER_BITS to handle rollover correctly.  Instead, we
 196        * report 36 bits and truncate at that (rolling over 5 times as often
 197        * as the HW counter), and when the 32-bit counter rolls over, it
 198        * happens to also be at a rollover in the reported value from near
 199        * (1<<36) to 0.
 200        *
 201        * The low 32 bits rolls over in ~343 seconds.  Our 36-bit result
 202        * rolls over every ~69 seconds.
 203        *
 204        * The query BO contains a single timestamp value in results[0].
 205        */
 206       query->Base.Result = 80 * (results[0] & 0xffffffff);
 207       query->Base.Result &= (1ull << 36) - 1;
 208       break;
 209
 210    case GL_SAMPLES_PASSED_ARB:
 211       /* We need to use += rather than = here since some BLT-based operations
 212        * may have added additional samples to our occlusion query value.
 213        */
 214       query->Base.Result += results[1] - results[0];
 215       break;
 216
 217    case GL_ANY_SAMPLES_PASSED:
 218    case GL_ANY_SAMPLES_PASSED_CONSERVATIVE:
 219       if (results[0] != results[1])
 220          query->Base.Result = true;
 221       break;
 222
 223    case GL_PRIMITIVES_GENERATED:
 224    case GL_TRANSFORM_FEEDBACK_PRIMITIVES_WRITTEN:
 225       query->Base.Result = results[1] - results[0];
 226       break;
 227
 228    default:
 229       assert(!"Unrecognized query target in brw_queryobj_get_results()");
 230       break;
 231    }
 232    drm_intel_bo_unmap(query->bo);
 233
 234    /* Now that we've processed the data stored in the query's buffer object,
 235     * we can release it.
 236     */
 237    drm_intel_bo_unreference(query->bo);
 238    query->bo = NULL;
 239 }
 240
 241 /**
 242  * Driver hook for glBeginQuery().
 243  *
 244  * Initializes driver structures and emits any GPU commands required to begin
 245  * recording data for the query.
 246  */
 247 static void
 248 gen6_begin_query(struct gl_context *ctx, struct gl_query_object *q)
 249 {
 250    struct brw_context *brw = brw_context(ctx);
 251    struct brw_query_object *query = (struct brw_query_object *)q;
 252
 253    /* Since we're starting a new query, we need to throw away old results. */
 254    drm_intel_bo_unreference(query->bo);
 255    query->bo = drm_intel_bo_alloc(brw->bufmgr, "query results", 4096, 4096);
 256
 257    switch (query->Base.Target) {
 258    case GL_TIME_ELAPSED:
 259       /* For timestamp queries, we record the starting time right away so that
 260        * we measure the full time between BeginQuery and EndQuery.  There's
 261        * some debate about whether this is the right thing to do.  Our decision
 262        * is based on the following text from the ARB_timer_query extension:
 263        *
 264        * "(5) Should the extension measure total time elapsed between the full
 265        *      completion of the BeginQuery and EndQuery commands, or just time
 266        *      spent in the graphics library?
 267        *
 268        *  RESOLVED:  This extension will measure the total time elapsed
 269        *  between the full completion of these commands.  Future extensions
 270        *  may implement a query to determine time elapsed at different stages
 271        *  of the graphics pipeline."
 272        *
 273        * We write a starting timestamp now (at index 0).  At EndQuery() time,
 274        * we'll write a second timestamp (at index 1), and subtract the two to
 275        * obtain the time elapsed.  Notably, this includes time elapsed while
 276        * the system was doing other work, such as running other applications.
 277        */
 278       write_timestamp(brw, query->bo, 0);
 279       break;
 280
 281    case GL_ANY_SAMPLES_PASSED:
 282    case GL_ANY_SAMPLES_PASSED_CONSERVATIVE:
 283    case GL_SAMPLES_PASSED_ARB:
 284       write_depth_count(brw, query->bo, 0);
 285       break;
 286
 287    case GL_PRIMITIVES_GENERATED:
 288       write_primitives_generated(brw, query->bo, 0);
 289       break;
 290
 291    case GL_TRANSFORM_FEEDBACK_PRIMITIVES_WRITTEN:
 292       write_xfb_primitives_written(brw, query->bo, 0);
 293       break;
 294
 295    default:
 296       assert(!"Unrecognized query target in brw_begin_query()");
 297       break;
 298    }
 299 }
 300
 301 /**
 302  * Driver hook for glEndQuery().
 303  *
 304  * Emits GPU commands to record a final query value, ending any data capturing.
 305  * However, the final result isn't necessarily available until the GPU processes
 306  * those commands.  brw_queryobj_get_results() processes the captured data to
 307  * produce the final result.
 308  */
 309 static void
 310 gen6_end_query(struct gl_context *ctx, struct gl_query_object *q)
 311 {
 312    struct brw_context *brw = brw_context(ctx);
 313    struct brw_query_object *query = (struct brw_query_object *)q;
 314
 315    switch (query->Base.Target) {
 316    case GL_TIME_ELAPSED:
 317       write_timestamp(brw, query->bo, 1);
 318       break;
 319
 320    case GL_ANY_SAMPLES_PASSED:
 321    case GL_ANY_SAMPLES_PASSED_CONSERVATIVE:
 322    case GL_SAMPLES_PASSED_ARB:
 323       write_depth_count(brw, query->bo, 1);
 324       break;
 325
 326    case GL_PRIMITIVES_GENERATED:
 327       write_primitives_generated(brw, query->bo, 1);
 328       break;
 329
 330    case GL_TRANSFORM_FEEDBACK_PRIMITIVES_WRITTEN:
 331       write_xfb_primitives_written(brw, query->bo, 1);
 332       break;
 333
 334    default:
 335       assert(!"Unrecognized query target in brw_end_query()");
 336       break;
 337    }
 338 }
 339
 340 /**
 341  * The WaitQuery() driver hook.
 342  *
 343  * Wait for a query result to become available and return it.  This is the
 344  * backing for glGetQueryObjectiv() with the GL_QUERY_RESULT pname.
 345  */
 346 static void gen6_wait_query(struct gl_context *ctx, struct gl_query_object *q)
 347 {
 348    struct brw_query_object *query = (struct brw_query_object *)q;
 349
 350    gen6_queryobj_get_results(ctx, query);
 351    query->Base.Ready = true;
 352 }
 353
 354 /**
 355  * The CheckQuery() driver hook.
 356  *
 357  * Checks whether a query result is ready yet.  If not, flushes.
 358  * This is the backing for glGetQueryObjectiv()'s QUERY_RESULT_AVAILABLE pname.
 359  */
 360 static void gen6_check_query(struct gl_context *ctx, struct gl_query_object *q)
 361 {
 362    struct brw_context *brw = brw_context(ctx);
 363    struct brw_query_object *query = (struct brw_query_object *)q;
 364
 365    /* From the GL_ARB_occlusion_query spec:
 366     *
 367     *     "Instead of allowing for an infinite loop, performing a
 368     *      QUERY_RESULT_AVAILABLE_ARB will perform a flush if the result is
 369     *      not ready yet on the first time it is queried.  This ensures that
 370     *      the async query will return true in finite time.
 371     */
 372    if (query->bo && drm_intel_bo_references(brw->batch.bo, query->bo))
 373       intel_batchbuffer_flush(brw);
 374
 375    if (query->bo == NULL || !drm_intel_bo_busy(query->bo)) {
 376       gen6_queryobj_get_results(ctx, query);
 377       query->Base.Ready = true;
 378    }
 379 }
 380
 381 /* Initialize Gen6+-specific query object functions. */
 382 void gen6_init_queryobj_functions(struct dd_function_table *functions)
 383 {
 384    functions->BeginQuery = gen6_begin_query;
 385    functions->EndQuery = gen6_end_query;
 386    functions->CheckQuery = gen6_check_query;
 387    functions->WaitQuery = gen6_wait_query;
 388 }