caddyhttp: presize buffers in hot paths to reduce allocations#7842
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jvoisin wants to merge 1 commit into
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caddyhttp: presize buffers in hot paths to reduce allocations#7842jvoisin wants to merge 1 commit into
jvoisin wants to merge 1 commit into
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Right-size three per-request allocations that previously grew from a
nil/empty backing array, causing repeated reallocation:
- CleanPath: pre-Grow the strings.Builder used when slash collapsing is
disabled, instead of letting it reallocate as runes are appended
- headers: presize the rewritten value slice in HeaderOps.ApplyTo's Set
loop instead of appending from nil
- reverseproxy: presize the weights slice in WeightedRoundRobinSelection
.Select
This commit also adds benchmarks exercising each path. Measured with benchstat
with count=20 and GOMAXPROCS=1, with p=0.000:
sec/op B/op allocs/op
CleanPathNoCollapse 1013.4n -> 828.6n (-18.23%) 120->64 (-46.67%) 4->1 (-75.00%)
HeaderOpsApplyToSet 1262.0n -> 955.8n (-24.27%) 255->152 (-40.39%) 9->6 (-33.33%)
WeightedRoundRobinSelect 215.8n -> 200.3n ( -7.20%) 112->96 (-14.29%) 2->2 (N/A)
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Right-size three per-request allocations that previously grew from a nil/empty backing array, causing repeated reallocation:
This commit also adds benchmarks exercising each path. Measured with benchstat with count=20 and GOMAXPROCS=1, with p=0.000:
CleanPathNoCollapse 1013.4n -> 828.6n (-18.23%) 120->64 (-46.67%) 4->1 (-75.00%)
HeaderOpsApplyToSet 1262.0n -> 955.8n (-24.27%) 255->152 (-40.39%) 9->6 (-33.33%)
WeightedRoundRobinSelect 215.8n -> 200.3n ( -7.20%) 112->96 (-14.29%) 2->2 (N/A)
Assistance Disclosure
I wrote the code, but Copilot generated the tests.