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Replace ConcurrentDictionary with lock-guarded flat arrays for EventContext field storage, preserving thread safety while eliminating hash table overhead and sort-on-render. Stopwatch replaced with Stopwatch.GetTimestamp() to avoid per-event object allocation. Lazy initialization for timers, counts, and PrivateData skips allocation when unused. Constructor batches field writes without locking since the object isn't yet shared. ThreadStatic StringBuilder reuse and single-pass key normalization reduce render allocations. Throughput: 179K -> 1,721K ops/sec (9.6x vs 6.4.7 release). Allocation: 12,450 -> 1,272 bytes/op (89.8% reduction). Adds benchmark harness and Benchmarks.Baseline project for NuGet package comparison.
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Problem
EventContext allocates heavily per event — 12,450 bytes/op in
v6.4.7 — driven by three ConcurrentDictionaries, a Stopwatch
object, LINQ-based sorting in Render(), and multiple dictionary
iteration passes for key normalization. At high event volumes
this creates significant GC pressure.
Approach
Targeted the allocation and compute hot paths while preserving
the existing thread-safety contract:
ConcurrentDictionarywith flatstring[]/object[]arrays guarded bylock. Linear scanfor key lookup is faster than hash tables at typical field
counts (<20). Insertion order is preserved naturally,
eliminating the sort in
Render().Stopwatchallocation withstatic
Stopwatch.GetTimestamp()arithmetic.TimerCollection,_counts, andPrivateDataare only allocated when actually used.the object isn't shared yet. Internal
SetCorepath avoidsdouble-locking in Render.
separate dictionary scans), ThreadStatic
StringBuilderreuse, cached quote-char strings.
Trade-off:
FindKeyis O(n) vs O(1) hash lookup. For thetypical 10-20 fields per event, the cache-friendly linear scan
is net faster because it avoids Dictionary's allocation and
hash overhead.
Results (.NET 10, 60s sustained)
Review guide
Start with EventContext.cs — the core storage change from
ConcurrentDictionary to flat arrays,
SetCore/FindKey/AppendEntry, and the restructuredRender(). ThenTimerCollection.cs (same ConcurrentDict removal pattern),
AutoTimer.cs (Stopwatch elimination), and
StringExtensions.cs (quote-char caching). The
Benchmarks.Baseline/project is a standalone harness thatreferences the 6.4.7 NuGet package for comparison.
Testing
All 56 existing unit tests pass. Throughput validated via
60-second sustained benchmark runs comparing against the
published 6.4.7 NuGet package baseline.