| commit | b94bd12401d26ccf1c3b04ceb4e950b0ff7c8d29 | [log] [tgz] |
|---|---|---|
| author | bors <bors@rust-lang.org> | Wed Jul 02 11:41:14 2025 +0000 |
| committer | bors <bors@rust-lang.org> | Wed Jul 02 11:41:14 2025 +0000 |
| tree | 5a3056b107ad7323d1008417cd5e2ebebe07340a | |
| parent | f51c9870bab634afb9e7a262b6ca7816bb9e940d [diff] | |
| parent | b49ca021e1569e219265651eb7bd936d5ac21886 [diff] |
Auto merge of #142978 - Kobzol:query-hit, r=oli-obk Add new self-profiling event to cheaply aggregate query cache hit counts Self-profile can record various types of things, some of them are not enabled, like query cache hits. Rustc currently records cache hits as "instant" measureme events, which records the thread ID, current timestamp, and constructs an individual event for each such cache hit. This is incredibly expensive, in a small hello world benchmark that just depends on serde, it makes compilation with nightly go from ~3s (with `-Zself-profile`) to ~15s (with `-Zself-profile -Zself-profile-events=default,query-cache-hit`). We'd like to add query cache hits to rustc-perf (https://github.com/rust-lang/rustc-perf/pull/2168), but there we only need the actualy cache hit counts, not the timestamp/thread ID metadata associated with it. This PR adds a new `query-cache-hit-count` event. Instead of generating individual instant events, it simply aggregates cache hit counts per *query invocation* (so a combination of a query and its arguments, if I understand it correctly) using an atomic counter. At the end of the compilation session, these counts are then dumped to the self-profile log using integer events (in a similar fashion as how we record artifact sizes). I suppose that we could dedup the query invocations in rustc directly, but I don't think it's really required. In local experiments with the hello world + serde case, the query invocation records generated ~30 KiB more data in the self-profile, which was ~10% increase in this case. With this PR, the overhead of `-Zself-profile` seems to be the same as before, at least on my machine, so I also enabled query cache hit counts by default when self profiling is enabled. We should also modify `analyzeme`, specifically [this](https://github.com/rust-lang/measureme/blob/master/analyzeme/src/analysis.rs#L139), and make it load the integer events with query cache hit counts. I can do that as a follow-up, it's not required to be done in sync with this PR, and it doesn't require changes in rustc. CC `@cjgillot` r? `@oli-obk`
Website | Getting started | Learn | Documentation | Contributing
This is the main source code repository for Rust. It contains the compiler, standard library, and documentation.
Performance: Fast and memory-efficient, suitable for critical services, embedded devices, and easily integrated with other languages.
Reliability: Our rich type system and ownership model ensure memory and thread safety, reducing bugs at compile-time.
Productivity: Comprehensive documentation, a compiler committed to providing great diagnostics, and advanced tooling including package manager and build tool (Cargo), auto-formatter (rustfmt), linter (Clippy) and editor support (rust-analyzer).
Read “Installation” from The Book.
If you really want to install from source (though this is not recommended), see INSTALL.md.
See https://www.rust-lang.org/community for a list of chat platforms and forums.
See CONTRIBUTING.md.
Rust is primarily distributed under the terms of both the MIT license and the Apache License (Version 2.0), with portions covered by various BSD-like licenses.
See LICENSE-APACHE, LICENSE-MIT, and COPYRIGHT for details.
The Rust Foundation owns and protects the Rust and Cargo trademarks and logos (the “Rust Trademarks”).
If you want to use these names or brands, please read the Rust language trademark policy.
Third-party logos may be subject to third-party copyrights and trademarks. See Licenses for details.