From 6f54204ec8d3fe515c74dad909e8aba8c8af2071 Mon Sep 17 00:00:00 2001 From: Matthew Jackson Date: Sat, 16 May 2026 09:30:44 -0700 Subject: [PATCH] =?UTF-8?q?Revert=20"io/pipeline:=20bump=20WRITE=5FPIPELIN?= =?UTF-8?q?E=5FDEPTH=2016=20=E2=86=92=2032"?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit This reverts commit 95cb0ea935fc9b519d3874465248561eacb6cde0. --- src/io/pipeline.rs | 14 ++++---------- 1 file changed, 4 insertions(+), 10 deletions(-) diff --git a/src/io/pipeline.rs b/src/io/pipeline.rs index f198873..91bb1db 100644 --- a/src/io/pipeline.rs +++ b/src/io/pipeline.rs @@ -92,16 +92,10 @@ pub const DEFAULT_PIPELINE_DEPTH: usize = 4; /// consumer blocks on write. pub const READ_PIPELINE_DEPTH: usize = 32; -/// Write pipeline depth. 0.21.8 restored the writer-thread + 128 MiB -/// byte-bounded ring inside WritebackFile, which absorbs kernel -/// writeback stalls downstream of this channel. The pre-0.21.8 -/// rationale ("smaller buffer reduces backpressure risk when -/// sync_file_range blocks") no longer applies — `sync_file_range` only -/// hits the writer thread, never this channel. Doubling 16 → 32 gives -/// the matroska builder headroom to keep emitting frames when the sink -/// momentarily lags behind, smoothing out the 5-50 MB/s instantaneous -/// burst pattern observed on NFS bidirectional workloads at 0.21.8. -pub const WRITE_PIPELINE_DEPTH: usize = 32; +/// Write pipeline depth. Smaller buffer reduces backpressure risk when +/// sync_file_range blocks; prevents producer from accumulating too much +/// work while consumer waits for NFS to drain. +pub const WRITE_PIPELINE_DEPTH: usize = 16; /// Channel depth for write-through pipelines. Each `send` fully /// drains before the next can enqueue. Use this when the producer