perf(formatter_core): share one thread-cached scratch vector across staging buffers by leaysgur · Pull Request #24583 · oxc-project/oxc

leaysgur · 2026-07-16T05:04:32Z

Apply #24539, share ScratchBuffer's buffer.

NOTE: checked-in vectors keep their high-water capacity for the thread's lifetime (same policy as #24539). This is ~KB for regular sources, and fine.

leaysgur · 2026-07-16T05:04:45Z

perf(formatter): stage assignment-like left hand side on the heap #24613 : 3 dependent PRs (#24631 , #24754 , #24793 )
perf(formatter): accumulate JSX child-list builders on the heap #24585
perf(formatter_core): share one thread-cached scratch vector across staging buffers #24583 👈 (View in Graphite)
perf(formatter_core): stage IR buffers on the heap to reduce arena memory #24582
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codspeed-hq · 2026-07-16T05:09:04Z

Merging this PR will not alter performance

✅ 57 untouched benchmarks
⏩ 19 skipped benchmarks¹

_{Comparing 07-16-perf_formatter_core_share_one_thread-cached_scratch_vector_across_staging_buffers (c3b460b) with 07-16-perf_formatter_core_stage_ir_buffers_on_the_heap_to_reduce_arena_memory (c880bce)²}

19 benchmarks were skipped, so the baseline results were used instead. If they were deleted from the codebase, click here and archive them to remove them from the performance reports. ↩
No successful run was found on 07-16-perf_formatter_core_stage_ir_buffers_on_the_heap_to_reduce_arena_memory (d7cedab) during the generation of this report, so 691cfca was used instead as the comparison base. There might be some changes unrelated to this pull request in this report. ↩

graphite-app · 2026-07-22T06:31:30Z

Merge activity

Jul 22, 6:31 AM UTC: leaysgur added this pull request to the Graphite merge queue.
Jul 22, 6:37 AM UTC: Merged by the Graphite merge queue.

…taging buffers (#24583) Apply #24539, share `ScratchBuffer`'s buffer. NOTE: checked-in vectors keep their high-water capacity for the thread's lifetime (same policy as #24539). This is ~KB for regular sources, and fine.

Revert #24583. After re-measuring, I found no significant improvement. It is not worth the amount of code required. Also, the fundamental issue is that the end-side formatter, rather than Oxfmt itself, is performing cross-file caching, which is an undesirable side effect.

leaysgur requested a review from overlookmotel as a code owner July 16, 2026 05:04

leaysgur mentioned this pull request Jul 16, 2026

perf(formatter_core): stage IR buffers on the heap to reduce arena memory #24582

Merged

github-actions Bot added the A-formatter Area - Formatter label Jul 16, 2026

leaysgur mentioned this pull request Jul 16, 2026

perf(formatter): accumulate JSX child-list builders on the heap #24585

Merged

leaysgur force-pushed the 07-16-perf_formatter_core_stage_ir_buffers_on_the_heap_to_reduce_arena_memory branch from aa1921c to 12a1158 Compare July 17, 2026 06:03

leaysgur force-pushed the 07-16-perf_formatter_core_share_one_thread-cached_scratch_vector_across_staging_buffers branch from 72ae10f to c835270 Compare July 17, 2026 06:03

This was referenced Jul 17, 2026

perf(formatter): stage assignment-like left hand side on the heap #24613

Merged

perf(formatter_core): pack FormatElement 24B to 16B #24631

Closed

leaysgur force-pushed the 07-16-perf_formatter_core_share_one_thread-cached_scratch_vector_across_staging_buffers branch from c835270 to 7aa30a3 Compare July 21, 2026 06:11

leaysgur force-pushed the 07-16-perf_formatter_core_stage_ir_buffers_on_the_heap_to_reduce_arena_memory branch from 12a1158 to 8039aca Compare July 21, 2026 06:11

leaysgur mentioned this pull request Jul 21, 2026

perf(formatter_core): take assignment staging from a state-owned spare slot #24754

Closed

leaysgur force-pushed the 07-16-perf_formatter_core_stage_ir_buffers_on_the_heap_to_reduce_arena_memory branch from 8039aca to c880bce Compare July 21, 2026 09:26

leaysgur force-pushed the 07-16-perf_formatter_core_share_one_thread-cached_scratch_vector_across_staging_buffers branch from 7aa30a3 to a9a2c78 Compare July 21, 2026 09:26

leaysgur force-pushed the 07-16-perf_formatter_core_stage_ir_buffers_on_the_heap_to_reduce_arena_memory branch from c880bce to d7cedab Compare July 22, 2026 05:04

leaysgur force-pushed the 07-16-perf_formatter_core_share_one_thread-cached_scratch_vector_across_staging_buffers branch from a9a2c78 to c3b460b Compare July 22, 2026 05:04

This was referenced Jul 22, 2026

perf(formatter_core): bound the thread-local scratch cache #24793

Merged

refactor(formatter_core): drop unused HeapVecBuffer methods #24796

Merged

graphite-app Bot added the 0-merge Merge with Graphite Merge Queue label Jul 22, 2026

graphite-app Bot force-pushed the 07-16-perf_formatter_core_stage_ir_buffers_on_the_heap_to_reduce_arena_memory branch from d7cedab to c191f51 Compare July 22, 2026 06:32

graphite-app Bot force-pushed the 07-16-perf_formatter_core_share_one_thread-cached_scratch_vector_across_staging_buffers branch from c3b460b to 7810e8a Compare July 22, 2026 06:32

Base automatically changed from 07-16-perf_formatter_core_stage_ir_buffers_on_the_heap_to_reduce_arena_memory to main July 22, 2026 06:36

graphite-app Bot removed the 0-merge Merge with Graphite Merge Queue label Jul 22, 2026

graphite-app Bot merged commit 7810e8a into main Jul 22, 2026
32 checks passed

graphite-app Bot deleted the 07-16-perf_formatter_core_share_one_thread-cached_scratch_vector_across_staging_buffers branch July 22, 2026 06:37

leaysgur mentioned this pull request Jul 23, 2026

refactor(formatter_core): remove thread-local scratch cache #24824

Merged

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perf(formatter_core): share one thread-cached scratch vector across staging buffers#24583

perf(formatter_core): share one thread-cached scratch vector across staging buffers#24583
graphite-app[bot] merged 1 commit into
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