Revert "Metrics: Log PMA UsedPct dynamically from processing processes" This reverts commit 7981ac03ebc0e68d3dc966100b1ea58ca66579ce. Reason for revert: crbug.com/536119038 , Crashes spiked on Windows Canary 152.0.7956.0 in the Chrome Installer process, reaching 43K+ crashes across 43k+ unique clients. Failure Link: crbug.com/536119038 , crash link : go/wjwsh Original change's description: > Metrics: Log PMA UsedPct dynamically from processing processes > > The UMA.PersistentAllocator.CrashpadMetrics.UsedPct metric was missing > because Crashpad does not have a background thread to call > PersistentMemoryAllocator::UpdateTrackingHistograms(). Previously, this > method computed the used percentage and wrote it to an internal > histogram (used_histogram_) within the .pma file, which was later > merged by the browser. > > This CL updates the design to report these metrics entirely from the > browser (or processing) process: > 1. Removed `used_histogram_` from PersistentMemoryAllocator. > 2. Updated PersistentMemoryAllocator::UpdateTrackingHistograms() to > log directly to the local StatisticsRecorder instead of writing to > the .pma file. > 3. Updated FileMetricsProvider to call UpdateTrackingHistograms() for > all processed source allocators, ensuring Crashpad's memory usage is > reported. > 4. Left CreateTrackingHistograms() as a no-op to maintain backward > compatibility with Crashpad upstream. > > TAG=agy > CONV=313cf72a-657a-421a-8952-7bc60505e694 > > Bug: 40282757 > Change-Id: I24f4fba3e1d640c88021e12ecefd3b2f233113f4 > Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/8057947 > Reviewed-by: Luc Nguyen <lucnguyen@google.com> > Commit-Queue: Roger McFarlane <rogerm@chromium.org> > Cr-Commit-Position: refs/heads/main@{#1663384} Bug: 40282757 , 536119038 Bug: 40282757 Change-Id: Id10f631ca3aa3871208ca5c11fa9bd64b77ca96f Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/8116370 Reviewed-by: Roger McFarlane <rogerm@chromium.org> Commit-Queue: Roger McFarlane <rogerm@chromium.org> Reviewed-by: Krishna Govind <govind@chromium.org> Bot-Commit: rubber-stamper@appspot.gserviceaccount.com <rubber-stamper@appspot.gserviceaccount.com> Commit-Queue: Prudhvikumar Bommana <pbommana@google.com> Cr-Commit-Position: refs/heads/main@{#1664256} NOKEYCHECK=True GitOrigin-RevId: ed4077599db35421e109f44d9fe94a2b86fb47fc
Contains a written down set of principles and other information on //base. Please add to it!
Chromium is a very mature project. Most things that are generally useful are already here and things not here aren't generally useful.
The bar for adding stuff to base is that it must have demonstrated wide applicability. Prefer to add things closer to where they're used (i.e. “not base”), and pull into base only when needed. In a project our size, sometimes even duplication is OK and inevitable.
Adding a new logging macro DPVELOG_NE is not more clear than just writing the stuff you want to log in a regular logging statement, even if it makes your calling code longer. Just add it to your own code.
If the code in question does not need to be used inside base, but will have multiple consumers across the codebase, consider placing it in a new directory under components/ instead.
base is written for the Chromium project and is not intended to be used outside it. Using base outside of src.git is explicitly not supported, and base makes no guarantees about API (or even ABI) stability (like all other code in Chromium). New code that depends on base/ must be in src.git. Code that's not in src.git but pulled in through DEPS (for example, v8) cannot use base.
Owners are added when a contributor has shown the above qualifications and when they express interest. There isn't an upper bound on the number of OWNERS.
Since the primitives provided by //base are used very widely, it is important to ensure they scale to the necessary workloads and perform well under all supported platforms. The base_perftests target is a suite of synthetic microbenchmarks that measure performance in various scenarios:
thread_local, the implementation in //base, the POSIX/WinAPI directly)Regressions in these benchmarks can generally by caused by 1) operating system changes, 2) compiler version or flag changes or 3) changes in //base code itself.
Rust code in base should be organized into very small crates, split up by function. Merging crates is sometimes unavoidable (due to dependency cycles or the orphaning rule).
Rust files should live near the equivalent C++ files (if any), and use the same naming scheme (for example, run_loop.rs, not run_loop_rust.rs).
When adding FFI shims, prefer separate _shim.h files rather than adding code to existing C++ files. This helps avoid circular dependencies with the //base target. It also avoids adding code to commonly-used headers, which can increase compile size by a lot.
Crates which you expect to be widely used should be added to the public_deps of the //base:base_rust target, so that developers can simply depend on //base:base_rust the same way they do with //base.