Skip to content

benchmarks.md

Latest commit

 

History

History
54 lines (41 loc) · 2.22 KB

benchmarks.md

File metadata and controls

54 lines (41 loc) · 2.22 KB
Raw

\page benchmarks Performance and benchmarks

Performance and benchmarks

The benchmark harness lives under bench/ and is disabled by default. Enable it with LOGIT_BENCH_ENABLE=ON; add LOGIT_BENCH_WITH_SPDLOG=ON for the optional spdlog comparison binaries.

cmake -S . -B build -DLOGIT_BENCH_ENABLE=ON
cmake --build build --target logit_bench
./build/bench/logit_bench

The harness records end-to-end latency from the logging call until delivery to the sink, together with aggregate throughput. It compares synchronous and asynchronous modes, null and file sinks, producer counts, and message sizes. Results are appended to bench/results/latency.csv; workload size can be reduced with LOGIT_BENCH_TOTAL and LOGIT_BENCH_WARMUP.

Interpreting results

The benchmark measures the complete path, not just formatter throughput. A LogIt++ call may parse argument names, build args_array, and optionally format values, while another logger may receive an already formatted string. Compare implementations within the same mode and configuration; these numbers are not a universal speed ranking.

The asynchronous measurement includes enqueue, worker wake-up/scheduling, and sink time. Results are sensitive to queue capacity, overflow policy, worker count, filesystem cache state, compiler, operating system, and hardware.

Historical snapshot

The repository includes a comparison snapshot from 2025-12-05 in bench/results/latency-2025-12-05-10k.csv:

  • workload: LOGIT_BENCH_TOTAL=10000, four producers, 200-byte messages;
  • metrics: median (p50) latency in nanoseconds and throughput in messages per second;
  • timestamp: 2025-12-05 03:18 UTC.

This is a historical, reproducible fixture rather than a current performance claim. Re-run the harness on the target hardware before making deployment or library-selection decisions.

Harness details

bench/LatencyRecorder.hpp preallocates slots and tracks Token {slot, t0_ns, active} and Summary {p50, p99, p999}. It exposes recorded(), wait_for_all(), and finalize() for end-to-end timing across producers and consumers. The LogIt adapter stores the benchmark slot in LogRecord::line; sinks call LatencyRecorder::complete_slot() when they observe a non-negative line number.