Markk116
a55f442315
Instrument the four suspect regions from bench/RPS: cache-lookup, cache-insert, sqlite-query, and gzip-decode, plus an asset-served progress point. New `ccc causal` subcommand runs the sweep against live traffic and prints a summary (optionally a .coz file and a ledger audit). Ran it under the same 80/20 hot-set workload as bench/RPS - see bench/CAUSAL.md for the methodology and results. Findings: - sqlite-query is the real bottleneck on a cache miss (+20.5% at a 50% speedup, roughly linear). - cache-lookup/cache-insert are noise-level (0-4%) - the O(n) recency-scan touch() bench/RPS flagged as a possible follow-up is not actually costing anything, so that's off the table. - Switched prepare() -> prepare_cached() on the query as the obvious fix; re-measured and it made no real difference (+20.0% -> +20.5%, within noise). Kept it anyway (strictly not worse), but it shows execution cost (B-tree lookup + BLOB copy) dominates over parse cost in that site. - gzip-decode barely gets exercised since real clients (and oha) negotiate gzip - not worth optimizing further. - Net conclusion: the existing CCC_CACHE_CAPACITY tuning from bench/RPS (+42-47% RPS) is the correct lever, and causal profiling explains why - every cache hit skips the one site that matters. Zero cost when the feature is off: causal_site!/progress! compile to no-ops without smarm-causal.
22 lines
788 B
TOML
22 lines
788 B
TOML
[package]
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name = "CCC"
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version = "0.1.0"
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edition = "2024"
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license = "AGPL-3.0-only"
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[features]
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# RFC 007 causal profiling in smarm. Off by default (same zero-cost
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# discipline as smarm itself): causal_site!/progress! call sites compile
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# to no-ops without it, and `ccc causal` is unavailable.
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causal = ["smarm/smarm-causal"]
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[dependencies]
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urus = { git = "https://git.kalsbeek.dev/Markk116/urus.git", tag = "v0.2.2" }
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# Pinned to the same tag urus itself depends on, so Cargo unifies both
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# into a single source id/copy of smarm (avoids duplicate #[global_allocator]).
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smarm = { git = "https://git.kalsbeek.dev/Markk116/smarm.git", tag = "v0.6.0" }
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rusqlite = { version = "0.31", features = ["bundled"] }
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flate2 = "1.0"
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serde = { version = "1", features = ["derive"] }
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serde_json = "1"
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