e4a5b11b97
## What? Adds performance optimizations for the common case of single-item lost follower operations in the turbo-tasks-backend aggregation update system, along with improved tracing capabilities for debugging. ## Why? When profiling turbopack operations, we observed that many aggregation update jobs involve only a single upper losing a single follower. The previous implementation always used vectors and iteration even for these single-item cases, adding unnecessary allocation overhead. Additionally, the existing `trace_aggregation_update` feature was incomplete (compilation errors) and lacked visibility into task data and operation statistics. ## How? ### Single-item optimization - Added a dedicated `InnerOfUpperLostFollower` job variant and `inner_of_upper_lost_follower` function to handle the single upper + single follower case without vector allocation - Optimized the plural variants (`InnerOfUppersLostFollowers`, `InnerOfUppersLostFollower`, `InnerOfUpperLostFollowers`) to delegate to the singular function when they contain only one item ### Tracing improvements - Added `trace_aggregation_update_stats` feature flag that enables counters for all aggregation update job types (new_followers, lost_followers, balance_edge, optimize_task, etc.) recorded in trace spans - Fixed `trace_aggregation_update` feature compilation errors by using `task.get_task_description()` instead of `ctx.get_task_description(task_id)` - Gated the `TaskDataCategory` used in aggregation update `ctx.task(...)` calls behind a const that resolves to `Meta` by default and `All` when tracing is enabled, so traces can see full task data without affecting default performance <!-- NEXT_JS_LLM_PR --> --------- Co-authored-by: Claude Opus 4.5 <[email protected]>
Next.js
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