instrument-bench

instrument-bench is a set of benchmarks comparing the overhead of various logging and instrumentation crates. These include:

Backends

• log
• tracing

Frontends

• env_logger
• tracing-subscriber (with the fmt subscriber layer)
• tracing-tracy (this is used in combination with tracing-subscriber just replacing the fmt layer in these tests)

Direct instrumentation

• tracy-client

The backends/frontends listed here are benchmarked in all possible combinations since they are all compatible.

How to use

cargo bench

Benchmark results

Note: I did not obtain these in a controlled environment and they can vary wildly (-50/+100 percent). However, the general relationships that are more than a factor of 2 apart should hold.

Benchmarks with instrumentation suppressed by a global or module specific filter.

instrumentation	env_logger	tracing-subscriber	tracing-tracy
Level::Info
log::debug!("")	1.6 ns	1.6 ns	1.9 ns
tracing::debug!("")	2.6 ns	3.8 ns	3.4 ns
tracing::debug_span!("")	39.4 ns	13.9 ns	14.4 ns
tracing::debug_span!("", "extra info")	48.3 ns	18.7 ns	15.0 ns
"mycrate::foo=error"*
log::info!("")	24.0 ns	81.7 ns	44.3 ns
tracing::info!("")	12.5 ns	3.0 ns	2.7 ns
tracing::info_span!("")	76.9 ns	19.4 ns	13.9 ns
tracing::info_span!("", "extra info")	86.32 ns	19.7 ns	14.5 ns

*For the info_span!("") "tracing::span=error" is needed to suppres it rather than using the module path because tracing spans report this as their module name to log frontends for spans that have no extra fields attached.

Benchmarks with an active span.

tracing-subscriber is using the fmt subscriber layer with a tracing span

tracy-tracing allows timing tracing spans with the Tracy profiler

tracy-client directly interfaces with the Tracy profiler

crate	time (ns)
tracing-subscriber	600
tracy-tracing	1062
tracy-client	205