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refactor(vanilla-epoll): extract shared emit_xcache helper for io_uring parity#966

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refactor(vanilla-epoll): extract shared emit_xcache helper for io_uring parity#966
enghitalo wants to merge 1 commit into
MDA2AV:mainfrom
enghitalo:refactor/vanilla-epoll-emit-xcache

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@enghitalo

@enghitalo enghitalo commented Jul 3, 2026

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What & why

Small maintainability refactor, paired with the vanilla-io_uring convergence PR. vanilla-epoll inlined the crud X-Cache response framing in two places (the crud GET cache hit and miss paths). This folds both into one emit_xcache helper.

The helper is byte-identical to the code it replaces, and identical to the emit_xcache now used by the vanilla-io_uring twin — so both entries share one audited X-Cache framing and diff cleanly. vanilla-epoll remains the performance reference; this only removes duplication.

Change

  • Add emit_xcache(mut out, ctype, body, cache) next to emit / write_resp.
  • Use it in start_crud_get (HIT) and render_crud_get (MISS).

No behavior or performance change.

Validation

Verified against a seeded Postgres that the crud GET MISS and HIT responses are byte-for-byte unchanged (and identical to the vanilla-io_uring twin, whose full-route byte-diff is covered in its PR).

🤖 Generated with Claude Code

@enghitalo @claude
refactor(vanilla-epoll): extract shared emit_xcache helper for crud X…
7aa1711 
…-Cache framing

Fold the two inlined X-Cache response framings (crud GET hit/miss) into one
emit_xcache helper — byte-identical output, and identical to the vanilla-io_uring
twin's emit_xcache, so both entries share one audited framing and diff cleanly.
No behavior or performance change (validated: crud GET MISS/HIT bytes unchanged).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
@enghitalo

enghitalo commented Jul 3, 2026

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/benchmark -f vanilla-epoll

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👋 /benchmark request received. A collaborator will review and approve the run.

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Benchmark Results

Framework: vanilla-epoll | Test: all tests

Test Conn RPS CPU Mem Δ RPS Δ Mem
baseline 512 3,664,027 6396.2% 77MiB -1.5% -1.3%
baseline 4096 4,078,658 6294.8% 154MiB -1.7% -3.1%
pipelined 512 39,394,796 6663.2% 73MiB -1.0% ~0%
pipelined 4096 39,802,857 6700.5% 163MiB -0.5% -0.6%
limited-conn 512 994,879 3188.1% 67MiB -0.7% ~0%
limited-conn 4096 1,015,795 3066.5% 99MiB -0.8% +39.4%
json 4096 2,151,652 6411.7% 185MiB -0.2% -2.6%
json-comp 512 2,103,334 6205.8% 82MiB +0.7% -13.7%
json-comp 4096 2,351,582 6457.6% 127MiB +1.2% -16.4%
json-comp 16384 2,326,732 6422.9% 172MiB +1.2% -34.1%
json-tls 4096 1,509,843 6125.5% 450MiB +0.6% +13.1%
upload 32 2,951 2112.6% 131MiB -0.2% -2.2%
upload 256 3,013 3744.3% 306MiB -0.1% -9.5%
api-4 256 67,006 399.6% 113MiB +6.1% +0.9%
api-16 1024 237,387 1332.8% 198MiB -3.7% +7.6%
static 1024 1,798,059 5734.3% 98MiB +0.2% +1.0%
static 4096 1,776,200 5712.6% 222MiB -0.2% -0.9%
static 6800 1,754,454 5380.1% 310MiB +1.1% -1.0%
async-db 1024 288,343 2999.7% 139MiB +0.3% -2.8%
crud 4096 313,530 787.8% 217MiB +0.9% -0.5%
fortunes 1024 168,464 6000.3% 255MiB +0.9% -0.8%
Full log 
  Templates: 20
  Expected:  200
  Duration:  15s


  Thread Stats   Avg      p50      p90      p99    p99.9
    Latency   11.30ms    876us   34.30ms   73.40ms   112.20ms

  4771944 requests in 15.00s, 4771946 responses
  Throughput: 318.07K req/s
  Bandwidth:  95.72MB/s
  Status codes: 2xx=4702958, 3xx=0, 4xx=0, 5xx=68988
  Latency samples: 4771943 / 4771946 responses (100.0%)
  Reconnects: 22313
  Per-template: 96798,120868,156281,187940,218868,249279,279198,305940,326336,339432,346967,352003,353963,354602,355605,358091,128212,63371,83386,94803
  Per-template-ok: 93268,119253,154108,185391,216094,245802,275408,301535,322055,334923,342130,347487,349383,349815,350890,353364,128212,61585,80712,91540

  WARNING: 68988/4771946 responses (1.4%) had unexpected status (expected 2xx)
[info] CPU 787.8% | Mem 217MiB

[run 2/3]
gcannon v0.5.3
  Target:    localhost:8080/
  Threads:   64
  Conns:     4096 (64/thread)
  Pipeline:  1
  Req/conn:  200
  Templates: 20
  Expected:  200
  Duration:  15s


  Thread Stats   Avg      p50      p90      p99    p99.9
    Latency   12.41ms   6.25ms   34.90ms   66.00ms   93.70ms

  4416611 requests in 15.00s, 4416419 responses
  Throughput: 294.38K req/s
  Bandwidth:  90.09MB/s
  Status codes: 2xx=4341662, 3xx=0, 4xx=0, 5xx=74757
  Latency samples: 4416415 / 4416419 responses (100.0%)
  Reconnects: 20475
  Per-template: 102200,120638,149934,176622,205341,234778,258692,282248,299246,305005,308650,310653,310636,312729,314104,312248,144166,78688,90353,99484
  Per-template-ok: 99137,118789,147654,173622,201820,230705,254409,277650,294037,299889,303630,305264,305615,307537,308821,307057,144166,77022,87630,97204

  WARNING: 74757/4416419 responses (1.7%) had unexpected status (expected 2xx)
[info] CPU 768.9% | Mem 227MiB

[run 3/3]
gcannon v0.5.3
  Target:    localhost:8080/
  Threads:   64
  Conns:     4096 (64/thread)
  Pipeline:  1
  Req/conn:  200
  Templates: 20
  Expected:  200
  Duration:  15s


  Thread Stats   Avg      p50      p90      p99    p99.9
    Latency   12.77ms   7.61ms   34.00ms   62.40ms   87.50ms

  4319316 requests in 15.00s, 4319316 responses
  Throughput: 287.91K req/s
  Bandwidth:  89.14MB/s
  Status codes: 2xx=4261635, 3xx=0, 4xx=0, 5xx=57681
  Latency samples: 4319311 / 4319316 responses (100.0%)
  Reconnects: 19860
  Per-template: 105613,121909,150361,176550,205127,231788,256053,276167,288293,295667,298383,297641,297792,296264,295572,294669,152529,84336,91432,103165
  Per-template-ok: 102848,120516,148413,174232,202202,228575,252875,272780,284570,291708,294612,293955,293978,292307,291816,290804,152529,82626,89422,100862

  WARNING: 57681/4319316 responses (1.3%) had unexpected status (expected 2xx)
[info] CPU 772.8% | Mem 232MiB

=== Best: 313530 req/s (CPU: 787.8%, Mem: 217MiB) ===
[info] input BW: 26.91MB/s (avg template: 90 bytes)
[info] saved results/crud/4096/vanilla-epoll.json
httparena-bench-vanilla-epoll
httparena-bench-vanilla-epoll

==============================================
=== vanilla-epoll / fortunes / 1024c (tool=gcannon) ===
==============================================
[info] resetting postgres for a clean per-profile baseline
[info] starting postgres sidecar
httparena-postgres
[info] postgres ready (seeded)
[info] waiting for server...
[info] server ready

[run 1/3]
gcannon v0.5.3
  Target:    localhost:8080/fortunes
  Threads:   64
  Conns:     1024 (16/thread)
  Pipeline:  1
  Req/conn:  unlimited (keep-alive)
  Expected:  200
  Duration:  5s


  Thread Stats   Avg      p50      p90      p99    p99.9
    Latency   4.66ms   3.68ms   8.55ms   15.40ms   32.20ms

  842320 requests in 5.00s, 842320 responses
  Throughput: 168.40K req/s
  Bandwidth:  3.90GB/s
  Status codes: 2xx=842320, 3xx=0, 4xx=0, 5xx=0
  Latency samples: 842319 / 842320 responses (100.0%)
[info] CPU 6000.3% | Mem 255MiB

[run 2/3]
gcannon v0.5.3
  Target:    localhost:8080/fortunes
  Threads:   64
  Conns:     1024 (16/thread)
  Pipeline:  1
  Req/conn:  unlimited (keep-alive)
  Expected:  200
  Duration:  5s


  Thread Stats   Avg      p50      p90      p99    p99.9
    Latency   4.72ms   3.88ms   8.86ms   14.30ms   19.00ms

  822880 requests in 5.00s, 822880 responses
  Throughput: 164.51K req/s
  Bandwidth:  3.81GB/s
  Status codes: 2xx=822880, 3xx=0, 4xx=0, 5xx=0
  Latency samples: 822876 / 822880 responses (100.0%)
[info] CPU 5969.6% | Mem 256MiB

[run 3/3]
gcannon v0.5.3
  Target:    localhost:8080/fortunes
  Threads:   64
  Conns:     1024 (16/thread)
  Pipeline:  1
  Req/conn:  unlimited (keep-alive)
  Expected:  200
  Duration:  5s


  Thread Stats   Avg      p50      p90      p99    p99.9
    Latency   4.83ms   4.20ms   8.79ms   13.40ms   17.70ms

  813881 requests in 5.00s, 813881 responses
  Throughput: 162.72K req/s
  Bandwidth:  3.77GB/s
  Status codes: 2xx=813881, 3xx=0, 4xx=0, 5xx=0
  Latency samples: 813876 / 813881 responses (100.0%)
[info] CPU 5838.8% | Mem 257MiB

=== Best: 168464 req/s (CPU: 6000.3%, Mem: 255MiB) ===
[info] saved results/fortunes/1024/vanilla-epoll.json
httparena-bench-vanilla-epoll
httparena-bench-vanilla-epoll
[info] skip: vanilla-epoll does not subscribe to baseline-h2
[info] skip: vanilla-epoll does not subscribe to static-h2
[info] skip: vanilla-epoll does not subscribe to baseline-h2c
[info] skip: vanilla-epoll does not subscribe to json-h2c
[info] skip: vanilla-epoll does not subscribe to baseline-h3
[info] skip: vanilla-epoll does not subscribe to static-h3
[info] skip: vanilla-epoll does not subscribe to gateway-64
[info] skip: vanilla-epoll does not subscribe to gateway-h3
[info] skip: vanilla-epoll does not subscribe to production-stack
[info] skip: vanilla-epoll does not subscribe to unary-grpc
[info] skip: vanilla-epoll does not subscribe to unary-grpc-tls
[info] skip: vanilla-epoll does not subscribe to stream-grpc
[info] skip: vanilla-epoll does not subscribe to stream-grpc-tls
[info] skip: vanilla-epoll does not subscribe to echo-ws
[info] skip: vanilla-epoll does not subscribe to echo-ws-pipeline
[info] rebuilding site/data/*.json
[updated] /home/diogo/actions-runner/_work/HttpArena/HttpArena/site/data/frameworks.json
[updated] /home/diogo/actions-runner/_work/HttpArena/HttpArena/site/data/api-16-1024.json
[updated] /home/diogo/actions-runner/_work/HttpArena/HttpArena/site/data/api-4-256.json
[updated] /home/diogo/actions-runner/_work/HttpArena/HttpArena/site/data/async-db-1024.json
[updated] /home/diogo/actions-runner/_work/HttpArena/HttpArena/site/data/baseline-4096.json
[updated] /home/diogo/actions-runner/_work/HttpArena/HttpArena/site/data/baseline-512.json
[updated] /home/diogo/actions-runner/_work/HttpArena/HttpArena/site/data/crud-4096.json
[updated] /home/diogo/actions-runner/_work/HttpArena/HttpArena/site/data/fortunes-1024.json
[updated] /home/diogo/actions-runner/_work/HttpArena/HttpArena/site/data/json-4096.json
[updated] /home/diogo/actions-runner/_work/HttpArena/HttpArena/site/data/json-comp-16384.json
[updated] /home/diogo/actions-runner/_work/HttpArena/HttpArena/site/data/json-comp-4096.json
[updated] /home/diogo/actions-runner/_work/HttpArena/HttpArena/site/data/json-comp-512.json
[updated] /home/diogo/actions-runner/_work/HttpArena/HttpArena/site/data/json-tls-4096.json
[updated] /home/diogo/actions-runner/_work/HttpArena/HttpArena/site/data/limited-conn-4096.json
[updated] /home/diogo/actions-runner/_work/HttpArena/HttpArena/site/data/limited-conn-512.json
[updated] /home/diogo/actions-runner/_work/HttpArena/HttpArena/site/data/pipelined-4096.json
[updated] /home/diogo/actions-runner/_work/HttpArena/HttpArena/site/data/pipelined-512.json
[updated] /home/diogo/actions-runner/_work/HttpArena/HttpArena/site/data/static-1024.json
[updated] /home/diogo/actions-runner/_work/HttpArena/HttpArena/site/data/static-4096.json
[updated] /home/diogo/actions-runner/_work/HttpArena/HttpArena/site/data/static-6800.json
[updated] /home/diogo/actions-runner/_work/HttpArena/HttpArena/site/data/upload-256.json
[updated] /home/diogo/actions-runner/_work/HttpArena/HttpArena/site/data/upload-32.json
[updated] /home/diogo/actions-runner/_work/HttpArena/HttpArena/site/data/current.json
[info] done
httparena-postgres
httparena-redis
[info] restoring loopback MTU to 65536

@enghitalo

enghitalo commented Jul 3, 2026

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/benchmark -f vanilla-epoll --save

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github-actions Bot commented Jul 3, 2026

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👋 /benchmark request received. A collaborator will review and approve the run.

@enghitalo enghitalo mentioned this pull request Jul 4, 2026
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@enghitalo

enghitalo commented Jul 4, 2026

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Superseded by #968 — same emit_xcache refactor, reopened clean on current main.

@enghitalo enghitalo closed this Jul 4, 2026
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