EA: use embedded CodeInstance directly for escape cache lookup
#56860
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vtjnash
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| - `token_symbol::Symbol = gensym(:EA)`: | ||
| specifies the cache token symbol to use, by default a new symbol is generated to ensure |
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gensym is somewhat expensive for this (since it is permanently allocated), and only ensures weak local uniqueness (it repeats values commonly). Is this the only way we have of being able to disable the cache?
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I think you just want mutable struct EscapeAnalyzerCacheToken; end here, so you are allocating a real unique token each time, though it is a bit of a mistake to put anonymous tokens in the global cache (it can make the runtime much slower)
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Yes, allocating a mutable struct might be a better approach. Since EAUtils.jl is primarily used for debugging and testing purposes, the impact on runtime performance from indiscriminately creating code caches should be limited.
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Apologies, it seems your concern was indeed valid. @benchmark code_escapes(...) is used frequently, and in such cases, it could lead to undesirable situations. #56868
vtjnash
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Dec 18, 2024
`Expr(:invoke)` now directly embeds `CodeInstance`, so `EscapeAnalysis` should also directly look it up when utilizing the cache. Similarly, the cache lookup mechanism in `EscapeAnalyzer` within EAUtils.jl has been updated. This update revealed a logic error in the previous `EscapeAnalyzer` implementation, resulting in one test being marked as `@test_broken`. A new test case addressing this logic error has also been added.
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In #56860, `EAUtils.EscapeAnalyzer` was updated to create a new cache for each invocation of `code_escapes`, similar to how Cthulhu.jl behaves. However, `code_escapes` is often used for performance analysis like `@benchmark code_escapes(...)`, and in such cases, a large number of `CodeInstance`s can be generated for each invocation. This could potentially impact native code execution. So this commit changes the default behavior so that `code_escapes` uses the same pre-existing cache by default. We can still opt-in to perform a fresh analysis by specifying `cache_token=EAUtils.EscapeAnalyzerCacheToken()`.
aviatesk
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In #56860, `EAUtils.EscapeAnalyzer` was updated to create a new cache for each invocation of `code_escapes`, similar to how Cthulhu.jl behaves. However, `code_escapes` is often used for performance analysis like `@benchmark code_escapes(...)`, and in such cases, a large number of `CodeInstance`s can be generated for each invocation. This could potentially impact native code execution. So this commit changes the default behavior so that `code_escapes` uses the same pre-existing cache by default. We can still opt-in to perform a fresh analysis by specifying `cache_token=EAUtils.EscapeAnalyzerCacheToken()`.
aviatesk
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In #56860, `EAUtils.EscapeAnalyzer` was updated to create a new cache for each invocation of `code_escapes`, similar to how Cthulhu.jl behaves. However, `code_escapes` is often used for performance analysis like `@benchmark code_escapes(...)`, and in such cases, a large number of `CodeInstance`s can be generated for each invocation. This could potentially impact native code execution. So this commit changes the default behavior so that `code_escapes` uses the same pre-existing cache by default. We can still opt-in to perform a fresh analysis by specifying `cache_token=EAUtils.EscapeAnalyzerCacheToken()`.
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Expr(:invoke)now directly embedsCodeInstance, soEscapeAnalysisshould also directly look it up when utilizing the cache. Similarly, the cache lookup mechanism inEscapeAnalyzerwithin EAUtils.jl has been updated. This update revealed a logic error in the previousEscapeAnalyzerimplementation, resulting in one test being marked as@test_broken. A new test case addressing this logic error has also been added.