From b93166a76005ffecae0dc8bd052acb9d7420ad07 Mon Sep 17 00:00:00 2001 From: tomasz-platek Date: Thu, 4 Jul 2024 15:35:56 +0200 Subject: [PATCH] Publish the cl_img_memory_management extension specification. --- extensions/cl_img_memory_management.asciidoc | 247 +++++++++++++++++++ extensions/extensions.txt | 2 + 2 files changed, 249 insertions(+) create mode 100644 extensions/cl_img_memory_management.asciidoc diff --git a/extensions/cl_img_memory_management.asciidoc b/extensions/cl_img_memory_management.asciidoc new file mode 100644 index 00000000..82a06bd7 --- /dev/null +++ b/extensions/cl_img_memory_management.asciidoc @@ -0,0 +1,247 @@ +:data-uri: +:icons: font +include::../config/attribs.txt[] +:source-highlighter: coderay + += cl_img_memory_management + +== Name Strings + +`cl_img_memory_management` + +== Contact + +Imagination Technologies Developer Forum: + +https://forums.imgtec.com/ + +Tomasz Platek, Imagination Technologies (Tomasz.Platek 'at' imgtec.com) + +== Contributors + +CY Cheng, Imagination Technologies. + +Tomasz Platek, Imagination Technologies. + +== Notice + +Copyright (c) 2024 Imagination Technologies Ltd. All Rights Reserved. + +== Status + +Draft spec, NOT APPROVED!! + +== Version + +Built On: {docdate} + +Version: Major.Minor.Patch + +== Dependencies + +This extension is written against the OpenCL C Specification Version V3.0.16. + +== Overview + +This extension adds built-in functions that expose the low-level memory and cache control instructions of Imagination GPU IP that are not accessible by standard OpenCL C functions. + +== New OpenCL C Feature Names + +[source,c] +---- +__opencl_img_fence +__opencl_img_cache +__opencl_img_load_store +---- + +== New OpenCL C Functions + +Issues a data fence: + +[source,c] +---- +void img_fence(cache_target_img target); +---- + +Perform the cache flush/invalidate operation: + +[source,c] +---- +void img_cache_flush(cache_target_img target); +void img_cache_invalidate(cache_target_img target); +void img_cache_flush_invalidate(cache_target_img target); +---- + +Load to/store from memory: + +[source,c] +---- +gentype img_load(gentype *p, cache_coherence_img coherence, L2_cache_policy_img policy, cache_persistence_level_img persistence, bool volatile); +gentype img_load(const gentype *p, cache_coherence_img coherence, L2_cache_policy_img policy, cache_persistence_level_img persistence, bool volatile); +void img_store(gentype *p, gentype value, cache_coherence_img coherence, L2_cache_policy_img policy, cache_persistence_level_img persistence, bool volatile); +---- + +== Modifications to the OpenCL C Specification + +(Add to Table 4 - Other Built-in Data Types in Section 6.3.3. Other Built-in Data Types) :: ++ +[cols=",",options="header",] +|==== +| Type | Description +| `cache_target_img` + | Target of the cache control functions. Refer to the Low-level Memory and Cache Control Functions section for a detailed description + of the built-in functions that use this enum. + +Requires that the `__opencl_img_fence` or the `__opencl_img_cache` feature macro is defined. +| `cache_coherence_img` + | Level of cache coherence. Refer to the Low-level Memory and Cache Control Functions section for a detailed description + of the built-in functions that use this enum. + +Requires that the `__opencl_img_load_store` feature macro is defined. +| `L2_cache_policy_img` + | Cache policy for the L2 cache. Refer to the Low-level Memory and Cache Control Functions section for a detailed description + of the built-in functions that use this enum. + +Requires that the `__opencl_img_load_store` feature macro is defined. +| `cache_persistence_level_img` + | Level of cache persistence. Refer to the Low-level Memory and Cache Control Functions section for a detailed description + of the built-in functions that use this enum. + +Requires that the `__opencl_img_load_store` feature macro is defined. +|==== + +(Add a new Section 6.15.22, *Low-level Memory and Cache Control Functions*) :: ++ +-- +The OpenCL C programming language implements the following built-in functions +to perform low-level memory and cache control operations: + +[cols="1,2",options="header"] +|==== +| Function | Description +| void *img_fence*(cache_target_img target) + a| `img_fence` issues a data fence as far as the specified `target`. For example, using `cache_target_L2_img` issues a data fence for the L1 and L2 caches. + +Requires that the `__opencl_img_fence` feature macro is defined. +| void *img_cache_flush*(cache_target_img target) + a| `img_cache_flush` flushes cache, `target` determines how far through the memory hierarchy caches are flushed. For example, using `cache_target_L2_img` flushes the L1 and L2 caches. + +Requires that the `__opencl_img_cache` feature macro is defined. +| void *img_cache_invalidate*(cache_target_img target) + a| `img_cache_invalidate` invalidates cache, `target` determines how far through the memory hierarchy caches are invalidated. For example, using `cache_target_L2_img` invalidates the L1 and L2 caches. + +Requires that the `__opencl_img_cache` feature macro is defined. +| void *img_cache_flush_invalidate*(cache_target_img target) + a| `img_cache_flush_invalidate` flushes and invalidates cache, `target` determines how far through the memory hierarchy caches are flushed and invalidated. For example, using `cache_target_L2_img` flushes and invalidates the L1 and L2 caches. + +Requires that the `__opencl_img_cache` feature macro is defined. +| gentype *img_load*(gentype pass:[*]p, cache_coherence_img coherence, L2_cache_policy_img policy, cache_persistence_level_img persistence, bool volatile) + + gentype *img_load*(const gentype pass:[*]p, cache_coherence_img coherence, L2_cache_policy_img policy, cache_persistence_level_img persistence, bool volatile) + a| `img_load` returns sizeof(gentype) bytes of data from `p`, where `coherence` specifies the level of cache coherence, `policy` specifies the cache policy for the L2 cache, `persistence` specifies the level of cache persistence, and `volatile` specifies volatility. + +Requires that the `__opencl_img_load_store` feature macro is defined. +| void *img_store*(gentype pass:[*]p, gentype value, cache_coherence_img coherence, L2_cache_policy_img policy, cache_persistence_level_img persistence, bool volatile) + a| `img_store` writes 'value' to `p`, where `coherence` specifies the level of cache coherence, `policy` specifies the cache policy for the L2 cache, `persistence` specifies the level of cache persistence, and `volatile` specifies volatility. + +Requires that the `__opencl_img_load_store` feature macro is defined. +|==== +-- + +=== Cache Target + +The enumerated type `cache_target_img` specifies the target of the cache control functions. +The following table lists the enumeration constants: + +[cols=",",options="header",] +|==== +| Cache Target | Additional Notes +| `cache_target_L1_img` + | Performs the operation on the L1 cache. + +Requires that the `__opencl_img_fence` or the `__opencl_img_cache` feature macro is defined. +| `cache_target_L2_img` + | Performs the operation on the L1 and L2 caches. + +Requires that the `__opencl_img_fence` or the `__opencl_img_cache` feature macro is defined. +| `cache_target_external_img` + | Performs the operation on the L1, L2, and external caches. + +Requires that the `__opencl_img_fence` or the `__opencl_img_cache` feature macro is defined. +|==== + +=== Cache Persistence +Cache persistence modifies the priority of the request in the cache where low level means that requests are evicted quickly and high level means that requests remain in cache for a long time. +The enumerated type `cache_persistence_level_img` specifies the level of cache persistence. +The following table lists the enumeration constants: + +[cols=",",options="header",] +|==== +| Cache Persistence | Additional Notes +| `cache_persistence_level_default_img` + | `cache_persistence_level_min_img` is the default persistence level. + +Requires that the `__opencl_img_load_store` feature macro is defined. +| `cache_persistence_level_min_img` + | Requires that the `__opencl_img_load_store` feature macro is defined. +| `cache_persistence_level_low_img` + | Requires that the `__opencl_img_load_store` feature macro is defined. +| `cache_persistence_level_high_img` + | Requires that the `__opencl_img_load_store` feature macro is defined. +| `cache_persistence_level_max_img` + | Requires that the `__opencl_img_load_store` feature macro is defined. +|==== + +[[cache-coherence]] +==== Cache Coherence +The enumerated type `cache_coherence_img` specifies the level of cache coherence. +The following table lists the enumeration constants: + +[cols=",",options="header",] +|==== +| Cache Coherence | Additional Notes +| `cache_coherence_L1_img` + | Cache coherence is guaranteed at the L1 level. Explicit flush or invalidate may be needed to ensure data coherency at higher levels. + +Requires that the `__opencl_img_load_store` feature macro is defined. +| `cache_coherence_L2_img` + | Cache coherence is guaranteed at the L2 level. Explicit flush or invalidate may be needed to ensure data coherency at higher levels. + +Requires that the `__opencl_img_load_store` feature macro is defined. +|==== + +=== L2 Cache Policy +The enumerated type `L2_cache_policy_img` specifies the cache policy for the L2 cache. +The following table lists the enumeration constants: + +[cols=",",options="header",] +|==== +| L2 Cache Policy | Additional Notes +| `L2_cache_policy_new_alloc_img` + | Allocates a new cache line on a cache miss. + +Requires that the `__opencl_img_load_store` feature macro is defined. +| `L2_cache_policy_new_alloc_bypass_img` + | Permits to bypass the cache and access memory directly. + +Requires that the `__opencl_img_load_store` feature macro is defined. +|==== + +== Coding Sample + +This coding sample shows how to use the *img_load* and *img_store* functions: +[source] +---- +__kernel void test(__global int *in, __global int *out) { + int a = img_load(in, cache_coherence_L1_img, L2_cache_policy_new_alloc_img, cache_persistence_level_min_img, true); + a += 1; + img_store(out, a, cache_coherence_L1_img, L2_cache_policy_new_alloc_img, cache_persistence_level_min_img, true); +} +---- + +== Version History + +[cols="5,15,15,70"] +[grid="rows"] +[options="header"] +|==== +| Version | Date | Author | Changes +| 1.0.0 | 2024-06-19 | Tomasz Platek | *Initial revision* +|==== + diff --git a/extensions/extensions.txt b/extensions/extensions.txt index 573ec116..deaf5c73 100644 --- a/extensions/extensions.txt +++ b/extensions/extensions.txt @@ -67,6 +67,8 @@ include::cl_img_cancel_command.asciidoc[] <<< include::cl_img_generate_mipmap.asciidoc[] <<< +include::cl_img_memory_management.asciidoc[] +<<< include::cl_img_mem_properties.asciidoc[] <<< include::cl_img_use_gralloc_ptr.asciidoc[]