[Mesa-dev] [PATCH v2 1/5] util/disk_cache: rename mesa cache dir and introduce cache versioning
Vedran Miletić
vedran at miletic.net
Wed Aug 23 11:35:14 UTC 2017
On 08/23/2017 08:32 AM, Timothy Arceri wrote:
> Steam is already analysing cache items, unfortunatly we did not
> introduce a versioning mechanism for identifying structural changes
> to cache entries earlier so the only way to do so is to rename the
> cache directory.
>
> Since we are renaming it we take the opportunity to give the directory
> a more meaningful name.
>
> Adding a version field to the header of cache entries will help us to
> avoid having to rename the directory in future. Please note this is
> versioning for the internal structure of the entries as defined in
> disk_cache.{c,h} as opposed to the structure of the data provided to
> the disk cache by the GLSL compiler and the various driver backends.
> ---
> src/compiler/glsl/tests/cache_test.c | 6 +++--
> src/util/disk_cache.c | 46 ++++++++++++++++++++++++++----------
> src/util/disk_cache.h | 2 ++
> 3 files changed, 40 insertions(+), 14 deletions(-)
>
> diff --git a/src/compiler/glsl/tests/cache_test.c b/src/compiler/glsl/tests/cache_test.c
> index af1b66fb3d..3796ce6170 100644
> --- a/src/compiler/glsl/tests/cache_test.c
> +++ b/src/compiler/glsl/tests/cache_test.c
> @@ -178,38 +178,40 @@ test_disk_cache_create(void)
> /* Test with XDG_CACHE_HOME set */
> setenv("XDG_CACHE_HOME", CACHE_TEST_TMP "/xdg-cache-home", 1);
> cache = disk_cache_create("test", "make_check", 0);
> expect_null(cache, "disk_cache_create with XDG_CACHE_HOME set with"
> "a non-existing parent directory");
>
> mkdir(CACHE_TEST_TMP, 0755);
> cache = disk_cache_create("test", "make_check", 0);
> expect_non_null(cache, "disk_cache_create with XDG_CACHE_HOME set");
>
> - check_directories_created(CACHE_TEST_TMP "/xdg-cache-home/mesa");
> + check_directories_created(CACHE_TEST_TMP "/xdg-cache-home/"
> + CACHE_DIR_NAME);
>
> disk_cache_destroy(cache);
>
> /* Test with MESA_GLSL_CACHE_DIR set */
> err = rmrf_local(CACHE_TEST_TMP);
> expect_equal(err, 0, "Removing " CACHE_TEST_TMP);
>
> setenv("MESA_GLSL_CACHE_DIR", CACHE_TEST_TMP "/mesa-glsl-cache-dir", 1);
> cache = disk_cache_create("test", "make_check", 0);
> expect_null(cache, "disk_cache_create with MESA_GLSL_CACHE_DIR set with"
> "a non-existing parent directory");
>
> mkdir(CACHE_TEST_TMP, 0755);
> cache = disk_cache_create("test", "make_check", 0);
> expect_non_null(cache, "disk_cache_create with MESA_GLSL_CACHE_DIR set");
>
> - check_directories_created(CACHE_TEST_TMP "/mesa-glsl-cache-dir/mesa");
> + check_directories_created(CACHE_TEST_TMP "/mesa-glsl-cache-dir/"
> + CACHE_DIR_NAME);
>
> disk_cache_destroy(cache);
> }
>
> static bool
> does_cache_contain(struct disk_cache *cache, const cache_key key)
> {
> void *result;
>
> result = disk_cache_get(cache, key, NULL);
> diff --git a/src/util/disk_cache.c b/src/util/disk_cache.c
> index b2229874e0..644a911e53 100644
> --- a/src/util/disk_cache.c
> +++ b/src/util/disk_cache.c
> @@ -51,20 +51,34 @@
>
> /* Number of bits to mask off from a cache key to get an index. */
> #define CACHE_INDEX_KEY_BITS 16
>
> /* Mask for computing an index from a key. */
> #define CACHE_INDEX_KEY_MASK ((1 << CACHE_INDEX_KEY_BITS) - 1)
>
> /* The number of keys that can be stored in the index. */
> #define CACHE_INDEX_MAX_KEYS (1 << CACHE_INDEX_KEY_BITS)
>
> +/* The cache version should be bumped whenever a change is made to the
> + * structure of cache entries or the index. This will give any 3rd party
> + * applications reading the cache entries a chance to adjust to the changes.
> + *
> + * - The cache version is checked internally when reading a cache entry. If we
> + * ever have a mismatch we are in big trouble as this means we had a cache
> + * collision. In case of such an event please check the skys for giant
> + * asteroids and that the entire Mesa team hasn't been eaten by wolves.
> + *
> + * - There is no strict requirement that cache versions be backwards
> + * compatible but effort should be taken to limit disruption where possible.
> + */
> +#define CACHE_VERSION 1
> +
> struct disk_cache {
> /* The path to the cache directory. */
> char *path;
>
> /* Thread queue for compressing and writing cache entries to disk */
> struct util_queue cache_queue;
>
> /* Seed for rand, which is used to pick a random directory */
> uint64_t seed_xorshift128plus[2];
>
> @@ -153,20 +167,25 @@ concatenate_and_mkdir(void *ctx, const char *path, const char *name)
> return NULL;
>
> new_path = ralloc_asprintf(ctx, "%s/%s", path, name);
>
> if (mkdir_if_needed(new_path) == 0)
> return new_path;
> else
> return NULL;
> }
>
> +#define DRV_KEY_CPY(_dst, _src, _src_size) { \
> + memcpy(_dst, _src, _src_size); \
> + _dst += _src_size; \
> +} while (0)
> +
> struct disk_cache *
> disk_cache_create(const char *gpu_name, const char *timestamp,
> uint64_t driver_flags)
> {
> void *local;
> struct disk_cache *cache = NULL;
> char *path, *max_size_str;
> uint64_t max_size;
> int fd = -1;
> struct stat sb;
> @@ -181,41 +200,41 @@ disk_cache_create(const char *gpu_name, const char *timestamp,
> if (local == NULL)
> goto fail;
>
> /* At user request, disable shader cache entirely. */
> if (getenv("MESA_GLSL_CACHE_DISABLE"))
> goto fail;
>
> /* Determine path for cache based on the first defined name as follows:
> *
> * $MESA_GLSL_CACHE_DIR
> - * $XDG_CACHE_HOME/mesa
> - * <pwd.pw_dir>/.cache/mesa
> + * $XDG_CACHE_HOME/mesa_shader_cache
> + * <pwd.pw_dir>/.cache/mesa_shader_cache
> */
Nitpick: since it's being changed, can it be
$XDG_CACHE_HOME/mesa-shader-cache instead of
$XDG_CACHE_HOME/mesa_shader_cache? I have seen both dashes and
underscores in the wild, but dashes tend to be more frequent.
Regards,
Vedran
> path = getenv("MESA_GLSL_CACHE_DIR");
> if (path) {
> if (mkdir_if_needed(path) == -1)
> goto fail;
>
> - path = concatenate_and_mkdir(local, path, "mesa");
> + path = concatenate_and_mkdir(local, path, CACHE_DIR_NAME);
> if (path == NULL)
> goto fail;
> }
>
> if (path == NULL) {
> char *xdg_cache_home = getenv("XDG_CACHE_HOME");
>
> if (xdg_cache_home) {
> if (mkdir_if_needed(xdg_cache_home) == -1)
> goto fail;
>
> - path = concatenate_and_mkdir(local, xdg_cache_home, "mesa");
> + path = concatenate_and_mkdir(local, xdg_cache_home, CACHE_DIR_NAME);
> if (path == NULL)
> goto fail;
> }
> }
>
> if (path == NULL) {
> char *buf;
> size_t buf_size;
> struct passwd pwd, *result;
>
> @@ -237,21 +256,21 @@ disk_cache_create(const char *gpu_name, const char *timestamp,
> buf_size *= 2;
> } else {
> goto fail;
> }
> }
>
> path = concatenate_and_mkdir(local, pwd.pw_dir, ".cache");
> if (path == NULL)
> goto fail;
>
> - path = concatenate_and_mkdir(local, path, "mesa");
> + path = concatenate_and_mkdir(local, path, CACHE_DIR_NAME);
> if (path == NULL)
> goto fail;
> }
>
> cache = ralloc(NULL, struct disk_cache);
> if (cache == NULL)
> goto fail;
>
> cache->path = ralloc_strdup(cache, path);
> if (cache->path == NULL)
> @@ -337,47 +356,50 @@ disk_cache_create(const char *gpu_name, const char *timestamp,
> cache->max_size = max_size;
>
> /* A limit of 32 jobs was choosen as observations of Deus Ex start-up times
> * showed that we reached at most 11 jobs on an Intel i5-6400 CPU at 2.70GHz
> * (a fairly modest desktop CPU). 1 thread was chosen because we don't
> * really care about getting things to disk quickly just that it's not
> * blocking other tasks.
> */
> util_queue_init(&cache->cache_queue, "disk_cache", 32, 1, 0);
>
> + uint8_t cache_version = CACHE_VERSION;
> + size_t cv_size = sizeof(cache_version);
> + cache->driver_keys_blob_size = cv_size;
> +
> /* Create driver id keys */
> size_t ts_size = strlen(timestamp) + 1;
> size_t gpu_name_size = strlen(gpu_name) + 1;
> - cache->driver_keys_blob_size = ts_size;
> + cache->driver_keys_blob_size += ts_size;
> cache->driver_keys_blob_size += gpu_name_size;
>
> /* We sometimes store entire structs that contains a pointers in the cache,
> * use pointer size as a key to avoid hard to debug issues.
> */
> uint8_t ptr_size = sizeof(void *);
> size_t ptr_size_size = sizeof(ptr_size);
> cache->driver_keys_blob_size += ptr_size_size;
>
> size_t driver_flags_size = sizeof(driver_flags);
> cache->driver_keys_blob_size += driver_flags_size;
>
> cache->driver_keys_blob =
> ralloc_size(cache, cache->driver_keys_blob_size);
> if (!cache->driver_keys_blob)
> goto fail;
>
> - memcpy(cache->driver_keys_blob, timestamp, ts_size);
> - memcpy(cache->driver_keys_blob + ts_size, gpu_name, gpu_name_size);
> - memcpy(cache->driver_keys_blob + ts_size + gpu_name_size, &ptr_size,
> - ptr_size_size);
> - memcpy(cache->driver_keys_blob + ts_size + gpu_name_size + ptr_size_size,
> - &driver_flags, driver_flags_size);
> + DRV_KEY_CPY(cache->driver_keys_blob, &cache_version, cv_size)
> + DRV_KEY_CPY(cache->driver_keys_blob, timestamp, ts_size)
> + DRV_KEY_CPY(cache->driver_keys_blob, gpu_name, gpu_name_size)
> + DRV_KEY_CPY(cache->driver_keys_blob, &ptr_size, ptr_size_size)
> + DRV_KEY_CPY(cache->driver_keys_blob, &driver_flags, driver_flags_size)
>
> /* Seed our rand function */
> s_rand_xorshift128plus(cache->seed_xorshift128plus, true);
>
> ralloc_free(local);
>
> return cache;
>
> fail:
> if (fd != -1)
> diff --git a/src/util/disk_cache.h b/src/util/disk_cache.h
> index 9aade16a9e..3521ef4a6b 100644
> --- a/src/util/disk_cache.h
> +++ b/src/util/disk_cache.h
> @@ -32,20 +32,22 @@
> #include <stdbool.h>
> #include <sys/stat.h>
>
> #ifdef __cplusplus
> extern "C" {
> #endif
>
> /* Size of cache keys in bytes. */
> #define CACHE_KEY_SIZE 20
>
> +#define CACHE_DIR_NAME "mesa_shader_cache"
> +
> typedef uint8_t cache_key[CACHE_KEY_SIZE];
>
> struct disk_cache;
>
> static inline bool
> disk_cache_get_function_timestamp(void *ptr, uint32_t* timestamp)
> {
> #ifdef ENABLE_SHADER_CACHE
> Dl_info info;
> struct stat st;
>
--
Vedran Miletić
vedran.miletic.net
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