dri/i965/brw_state_cache.c

/*
 Copyright (C) Intel Corp.  2006.  All Rights Reserved.
 Intel funded Tungsten Graphics (http://www.tungstengraphics.com) to
 develop this 3D driver.

 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 COPYRIGHT OWNER(S) AND/OR ITS SUPPLIERS 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:
  *   Keith Whitwell <keith@tungstengraphics.com>
  */

/** @file brw_state_cache.c
 *
 * This file implements a simple static state cache for 965.  The
 * consumers can query the hash table of state using a cache_id,
 * opaque key data, and receive the corresponding state buffer object
 * of state (plus associated auxiliary data) in return.  Objects in
 * the cache may not have relocations (pointers to other BOs) in them.
 *
 * The inner workings are a simple hash table based on a CRC of the
 * key data.
 *
 * Replacement is not implemented.  Instead, when the cache gets too
 * big we throw out all of the cache data and let it get regenerated.
 */

#include "main/imports.h"
#include "intel_batchbuffer.h"
#include "brw_state.h"

#define FILE_DEBUG_FLAG DEBUG_STATE

static GLuint
hash_key(struct brw_cache_item *item)
{
   GLuint *ikey = (GLuint *)item->key;
   GLuint hash = item->cache_id, i;

   assert(item->key_size % 4 == 0);

   /* I'm sure this can be improved on:
    */
   for (i = 0; i < item->key_size/4; i++) {
      hash ^= ikey[i];
      hash = (hash << 5) | (hash >> 27);
   }

   return hash;
}

static int
brw_cache_item_equals(const struct brw_cache_item *a,
		      const struct brw_cache_item *b)
{
   return a->cache_id == b->cache_id &&
      a->hash == b->hash &&
      a->key_size == b->key_size &&
      (memcmp(a->key, b->key, a->key_size) == 0);
}

static struct brw_cache_item *
search_cache(struct brw_cache *cache, GLuint hash,
	     struct brw_cache_item *lookup)
{
   struct brw_cache_item *c;

#if 0
   int bucketcount = 0;

   for (c = cache->items[hash % cache->size]; c; c = c->next)
      bucketcount++;

   fprintf(stderr, "bucket %d/%d = %d/%d items\n", hash % cache->size,
	   cache->size, bucketcount, cache->n_items);
#endif

   for (c = cache->items[hash % cache->size]; c; c = c->next) {
      if (brw_cache_item_equals(lookup, c))
	 return c;
   }

   return NULL;
}


static void
rehash(struct brw_cache *cache)
{
   struct brw_cache_item **items;
   struct brw_cache_item *c, *next;
   GLuint size, i;

   size = cache->size * 3;
   items = (struct brw_cache_item**) calloc(1, size * sizeof(*items));

   for (i = 0; i < cache->size; i++)
      for (c = cache->items[i]; c; c = next) {
	 next = c->next;
	 c->next = items[c->hash % size];
	 items[c->hash % size] = c;
      }

   FREE(cache->items);
   cache->items = items;
   cache->size = size;
}


/**
 * Returns the buffer object matching cache_id and key, or NULL.
 */
bool
brw_search_cache(struct brw_cache *cache,
                 enum brw_cache_id cache_id,
                 const void *key, GLuint key_size,
                 uint32_t *inout_offset, void *out_aux)
{
   struct brw_context *brw = cache->brw;
   struct brw_cache_item *item;
   struct brw_cache_item lookup;
   GLuint hash;

   lookup.cache_id = cache_id;
   lookup.key = key;
   lookup.key_size = key_size;
   hash = hash_key(&lookup);
   lookup.hash = hash;

   item = search_cache(cache, hash, &lookup);

   if (item == NULL)
      return false;

   *(void **)out_aux = ((char *)item->key + item->key_size);

   if (item->offset != *inout_offset) {
      brw->state.dirty.cache |= (1 << cache_id);
      *inout_offset = item->offset;
   }

   return true;
}

static void
brw_cache_new_bo(struct brw_cache *cache, uint32_t new_size)
{
   struct brw_context *brw = cache->brw;
   struct intel_context *intel = &brw->intel;
   drm_intel_bo *new_bo;

   new_bo = drm_intel_bo_alloc(intel->bufmgr, "program cache", new_size, 64);

   /* Copy any existing data that needs to be saved. */
   if (cache->next_offset != 0) {
      drm_intel_bo_map(cache->bo, false);
      drm_intel_bo_subdata(new_bo, 0, cache->next_offset, cache->bo->virtual);
      drm_intel_bo_unmap(cache->bo);
   }

   drm_intel_bo_unreference(cache->bo);
   cache->bo = new_bo;
   cache->bo_used_by_gpu = false;

   /* Since we have a new BO in place, we need to signal the units
    * that depend on it (state base address on gen5+, or unit state before).
    */
   brw->state.dirty.brw |= BRW_NEW_PROGRAM_CACHE;
}

/**
 * Attempts to find an item in the cache with identical data and aux
 * data to use
 */
static bool
brw_try_upload_using_copy(struct brw_cache *cache,
			  struct brw_cache_item *result_item,
			  const void *data,
			  const void *aux)
{
   int i;
   struct brw_cache_item *item;

   for (i = 0; i < cache->size; i++) {
      for (item = cache->items[i]; item; item = item->next) {
	 const void *item_aux = item->key + item->key_size;
	 int ret;

	 if (item->cache_id != result_item->cache_id ||
	     item->size != result_item->size ||
	     item->aux_size != result_item->aux_size) {
	    continue;
	 }

	 if (memcmp(item_aux, aux, item->aux_size) != 0) {
	    continue;
	 }

	 drm_intel_bo_map(cache->bo, false);
	 ret = memcmp(cache->bo->virtual + item->offset, data, item->size);
	 drm_intel_bo_unmap(cache->bo);
	 if (ret)
	    continue;

	 result_item->offset = item->offset;

	 return true;
      }
   }

   return false;
}

static void
brw_upload_item_data(struct brw_cache *cache,
		     struct brw_cache_item *item,
		     const void *data)
{
   /* Allocate space in the cache BO for our new program. */
   if (cache->next_offset + item->size > cache->bo->size) {
      uint32_t new_size = cache->bo->size * 2;

      while (cache->next_offset + item->size > new_size)
	 new_size *= 2;

      brw_cache_new_bo(cache, new_size);
   }

   /* If we would block on writing to an in-use program BO, just
    * recreate it.
    */
   if (cache->bo_used_by_gpu) {
      brw_cache_new_bo(cache, cache->bo->size);
   }

   item->offset = cache->next_offset;

   /* Programs are always 64-byte aligned, so set up the next one now */
   cache->next_offset = ALIGN(item->offset + item->size, 64);
}

void
brw_upload_cache(struct brw_cache *cache,
		 enum brw_cache_id cache_id,
		 const void *key,
		 GLuint key_size,
		 const void *data,
		 GLuint data_size,
		 const void *aux,
		 GLuint aux_size,
		 uint32_t *out_offset,
		 void *out_aux)
{
   struct brw_cache_item *item = CALLOC_STRUCT(brw_cache_item);
   GLuint hash;
   void *tmp;

   item->cache_id = cache_id;
   item->size = data_size;
   item->key = key;
   item->key_size = key_size;
   item->aux_size = aux_size;
   hash = hash_key(item);
   item->hash = hash;

   /* If we can find a matching prog/prog_data combo in the cache
    * already, then reuse the existing stuff.  This will mean not
    * flagging CACHE_NEW_* when transitioning between the two
    * equivalent hash keys.  This is notably useful for programs
    * generating shaders at runtime, where multiple shaders may
    * compile to the thing in our backend.
    */
   if (!brw_try_upload_using_copy(cache, item, data, aux)) {
      brw_upload_item_data(cache, item, data);
   }

   /* Set up the memory containing the key and aux_data */
   tmp = malloc(key_size + aux_size);

   memcpy(tmp, key, key_size);
   memcpy(tmp + key_size, aux, aux_size);

   item->key = tmp;

   if (cache->n_items > cache->size * 1.5)
      rehash(cache);

   hash %= cache->size;
   item->next = cache->items[hash];
   cache->items[hash] = item;
   cache->n_items++;

   /* Copy data to the buffer */
   drm_intel_bo_subdata(cache->bo, item->offset, data_size, data);

   *out_offset = item->offset;
   *(void **)out_aux = (void *)((char *)item->key + item->key_size);
   cache->brw->state.dirty.cache |= 1 << cache_id;
}

void
brw_init_caches(struct brw_context *brw)
{
   struct intel_context *intel = &brw->intel;
   struct brw_cache *cache = &brw->cache;

   cache->brw = brw;

   cache->size = 7;
   cache->n_items = 0;
   cache->items = (struct brw_cache_item **)
      calloc(1, cache->size * sizeof(struct brw_cache_item));

   cache->bo = drm_intel_bo_alloc(intel->bufmgr,
				  "program cache",
				  4096, 64);
}

static void
brw_clear_cache(struct brw_context *brw, struct brw_cache *cache)
{
   struct intel_context *intel = &brw->intel;
   struct brw_cache_item *c, *next;
   GLuint i;

   DBG("%s\n", __FUNCTION__);

   for (i = 0; i < cache->size; i++) {
      for (c = cache->items[i]; c; c = next) {
	 next = c->next;
	 free((void *)c->key);
	 free(c);
      }
      cache->items[i] = NULL;
   }

   cache->n_items = 0;

   /* Start putting programs into the start of the BO again, since
    * we'll never find the old results.
    */
   cache->next_offset = 0;

   /* We need to make sure that the programs get regenerated, since
    * any offsets leftover in brw_context will no longer be valid.
    */
   brw->state.dirty.mesa |= ~0;
   brw->state.dirty.brw |= ~0;
   brw->state.dirty.cache |= ~0;
   intel_batchbuffer_flush(intel);
}

void
brw_state_cache_check_size(struct brw_context *brw)
{
   /* un-tuned guess.  Each object is generally a page, so 2000 of them is 8 MB of
    * state cache.
    */
   if (brw->cache.n_items > 2000) {
      perf_debug("Exceeded state cache size limit.  Clearing the set "
                 "of compiled programs, which will trigger recompiles\n");
      brw_clear_cache(brw, &brw->cache);
   }
}


static void
brw_destroy_cache(struct brw_context *brw, struct brw_cache *cache)
{

   DBG("%s\n", __FUNCTION__);

   drm_intel_bo_unreference(cache->bo);
   cache->bo = NULL;
   brw_clear_cache(brw, cache);
   free(cache->items);
   cache->items = NULL;
   cache->size = 0;
}


void
brw_destroy_caches(struct brw_context *brw)
{
   brw_destroy_cache(brw, &brw->cache);
}