RFC-0051-Structured-call_hierarchy-metadata-for-FX-nodes#92
RFC-0051-Structured-call_hierarchy-metadata-for-FX-nodes#92andrewd-aws wants to merge 1 commit intopytorch:masterfrom
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| The implementation builds on existing Dynamo infrastructure. During proxy creation, `stack_trace` is already built by walking the InstructionTranslator (tx) parent chain. `call_hierarchy` is built during the same walk: at each frame, if `nn_module_stack` has new keys compared to the previous frame, the frame is a module entry; otherwise it is a function entry (filtered for torch-internal and non-meaningful frames). Because both module and function entries come from the same ordered traversal, the interleaving is correct by construction. This works regardless of how modules override `__call__` or `forward`. Module invocation counts come from `nn_module_stack`'s existing `@N` key suffix. Function invocation counts are tracked via a `function_call_counts` dict shared across the tx chain, incremented when `InliningInstructionTranslator` is created. | ||
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| We can gate the feature by `torch._dynamo.config.record_call_hierarchy` (default `False`). When disabled, zero additional work is performed. Or, if overhead is low enough have it on by default. |
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I think this is an interesting callout - from the prototyped implementation, do we have a feeling for the runtime overhead?
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We're actively working on getting some numbers on this
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| ## Alternatives | ||
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| - Parse `stack_trace` strings at consumption time. This is what consumers do today and it is fragile, lacks invocation counts, and cannot be correctly interleaved with `nn_module_stack`. |
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I'mm interested in why this is fragile. stack_trace gives you the exact line, which one can use for line-level profiling and etc. Can you give a little more detail on why the new proposal would be easier to use than stack_trace?
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Would be helpful if you can describe a concrete use-case for the new node meta.
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RFC for call hierarchy metadata