* caddyhttp: presize buffers in hot paths to reduce allocations
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)
* caddyhttp: presize strings.Builder in query rewrite and path matcher
Two builders whose output size is bounded by a known input length were
growing from empty, causing repeated reallocation. Seed each with a
capacity hint:
- rewrite.buildQueryString: pre-Grow to len(qs) (runs per request when
rewrite query manipulation is configured)
- MatchPath.matchPatternWithEscapeSequence: pre-Grow to len(escapedPath)
(reached only when a path pattern contains % escape sequences)
Adds a benchmark for buildQueryString, measured with benchstat:
BuildQueryString:
- sec/op 965.2n -> 743.3n (-22.99%)
- B/op 248->80 (-67.74%)
- allocs/op 5->1 (-80.00%)
The builder previously reallocated four times per call. The matcher path
is cold and not separately benchmarked.
* chore: add benchmark headers
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Signed-off-by: Julien Voisin <jvoisin@users.noreply.github.com>
c8492563ee