Add fetch span #875
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Add fetch span #875
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CodSpeed Performance ReportMerging #875 will not alter performanceComparing Summary
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Hmm, perf is definetely regressing :( |
Veykril
reviewed
May 22, 2025
| @@ -15,14 +15,17 @@ where | |||
| let (zalsa, zalsa_local) = db.zalsas(); | |||
| zalsa.unwind_if_revision_cancelled(zalsa_local); | |||
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| let database_key_index = self.database_key_index(id); | |||
| let _span = tracing::debug_span!("fetch", query = ?database_key_index).entered(); | |||
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I assume its just the allocation and deallocation of the span causing the perf regression but could you try using a query = ?{database_key_index} to force a move? (or inline the local into the method call). Rust's formatting infra captures the address of things which may inhibit optimizations.
MichaReiser
commented
May 22, 2025
| @@ -15,14 +15,18 @@ where | |||
| let (zalsa, zalsa_local) = db.zalsas(); | |||
| zalsa.unwind_if_revision_cancelled(zalsa_local); | |||
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| let database_key_index = self.database_key_index(id); | |||
| #[cfg(debug_assertions)] | |||
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This sort of defeats the purpose of tracing but I hopefully will never have to debug release-mode only salsa bugs
carljm
approved these changes
May 22, 2025
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I often find it hard to understand the query stack when debugging salsa.
This PR adds a
fetchspan, including the ingredient. This gives a better sense for how salsa recurses and (when enter and exit logging is enabled), when a query completes.This is a separate PR to see how it affects perf:
Example from a recent debugging sesison of mine (the thread id part is custom)