pytorch

af968cd6 - [Pytorch Mobile] Remove caching (in code) of interned strings (#50390)

[Pytorch Mobile] Remove caching (in code) of interned strings (#50390) Summary: Pull Request resolved: https://github.com/pytorch/pytorch/pull/50390 Currently, there is a massive switch/case statement that is generated in the `InternedStrings::string()` method to speed up Symbol -> string conversion without taking a lock (mutex). The relative call rate of this on mobile is insignificant, so unlikely to have any material impact on runtime even if the lookups happen under a lock. Plus, parallelism is almost absent on mobile, which is where locks/mutexes cause the most problem (taking a mutex without contention is usually very fast and just adds a memory barrier iirc). The only impact that caching interned strings has is avoiding taking a lock when interned strings are looked up. They are not looked up very often during training, and based on basic testing, they don't seem to be looked up much during inference either. During training, the following strings were looked up at test startup: ``` prim::profile prim::profile_ivalue prim::profile_optional prim::FusionGroup prim::TypeCheck prim::FallbackGraph prim::ChunkSizes prim::ConstantChunk prim::tolist prim::FusedConcat prim::DifferentiableGraph prim::MMBatchSide prim::TensorExprGroup ``` Command used to trigger training: `buck test fbsource//xplat/papaya/client/executor/torch/store/transform/feature/test:test` During inference, the only symbol that was looked up was `tolist`. ghstack-source-id: 119679831 Test Plan: See the summary above + sandcastle tests. ### Size test: fbios ``` D25861786-V1 (https://www.internalfb.com/intern/diff/D25861786/?dest_number=119641372) fbios: Succeeded Change in Download Size for arm64 + 3x assets variation: -13.9 KiB Change in Uncompressed Size for arm64 + 3x assets variation: -41.7 KiB Mbex Comparison: https://our.intern.facebook.com/intern/mbex/bsb:747386759232352@base/bsb:747386759232352@diff/ ``` ### Size test: igios ``` D25861786-V1 (https://www.internalfb.com/intern/diff/D25861786/?dest_number=119641372) igios: Succeeded Change in Download Size for arm64 + 3x assets variation: -16.6 KiB Change in Uncompressed Size for arm64 + 3x assets variation: -42.0 KiB Mbex Comparison: https://our.intern.facebook.com/intern/mbex/bsb:213166470538954@base/bsb:213166470538954@diff/ ``` Reviewed By: iseeyuan Differential Revision: D25861786 fbshipit-source-id: 34a55d693edc41537300f628877a64723694f8f0