Add write-data-frame-region for zero-copy DATA frame sending#7
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jcmallery wants to merge 1 commit into
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Add write-data-frame-region for zero-copy DATA frame sending#7jcmallery wants to merge 1 commit into
jcmallery wants to merge 1 commit into
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write-data-frame-region accepts a source buffer with offset and length instead of a whole octet vector. This eliminates an intermediate subseq allocation when sending large responses as multiple DATA frames. Use case: when splitting a 64KB response buffer into four 16KB DATA frames, each frame previously required: 1. (subseq buffer start (+ start 16384)) — 16KB alloc + copy 2. write-frame's replace into frame buffer — 16KB copy With write-data-frame-region, only step 2 remains (single copy from the source region directly into the frame buffer). Tested in CL-HTTP's HTTP/2 server on SBCL: 75 MB/s throughput for 10MB files, 1000 concurrent requests with zero failures.
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Thanks for the discussion. The function is now in v2.0.5 implemented a slightly different way. |
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Summary
write-data-frame-regiontocore/frames/data.lispwrite-data-framebut accepts source buffer + offset + lengthsubseqallocationMotivation
When sending large HTTP/2 responses as multiple DATA frames (e.g., splitting a 64KB buffer into four 16KB frames), each frame currently requires:
(subseq buffer start (+ start 16384))— 16KB allocation + copywrite-frame'sreplaceinto the frame buffer — 16KB copyWith
write-data-frame-region, only step 2 remains (single copy directly from the source region).This eliminates ~64 MB/s of nursery consing at peak throughput in CL-HTTP's HTTP/2 server.
Testing
Tested extensively in CL-HTTP on SBCL:
API
Thank you for the excellent http2 library!
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