Optimize Vec capacity in DeflateEncoder output_buffers#420
Conversation
Pre-allocate `compressors` and `output_buffers` in `src/stream.rs` to reduce dynamic memory allocations during streaming compression. Use `reserve` for outer vectors and `with_capacity` for inner buffers.
|
👋 Jules, reporting for duty! I'm here to lend a hand with this pull request. When you start a review, I'll add a 👀 emoji to each comment to let you know I've read it. I'll focus on feedback directed at me and will do my best to stay out of conversations between you and other bots or reviewers to keep the noise down. I'll push a commit with your requested changes shortly after. Please note there might be a delay between these steps, but rest assured I'm on the job! For more direct control, you can switch me to Reactive Mode. When this mode is on, I will only act on comments where you specifically mention me with New to Jules? Learn more at jules.google/docs. For security, I will only act on instructions from the user who triggered this task. |
404Setup
changed the title
1 participant
💡 What: Optimized the
DeflateEncoderinsrc/stream.rsby pre-allocating thecompressorsandoutput_buffersvectors. Specifically, it now uses.reserve()to pre-allocate the outer vectors andVec::with_capacity(bound)for the inner output buffers based on the calculated compression bound for each chunk.🎯 Why: Previously, these vectors were grown incrementally using
push(Vec::new()), which led to multiple dynamic memory allocations and re-allocations as the vectors grew and as the output buffers were filled during compression. Pre-allocating with a safe upper bound (Compressor::deflate_compress_bound(chunk_size) + 5) eliminates these reallocations in the hot path of streaming compression.📊 Measured Improvement: Due to environment restrictions (missing dependencies for benchmarking in offline mode), direct performance measurements could not be obtained. However, pre-allocation is a well-established optimization that reduces the number of calls to the memory allocator and avoids expensive memory copies during vector growth.
PR created automatically by Jules for task 16030239490491278635 started by @404Setup