CsvReporter

CsvReporter writes results to a .csv file with all computed statistics, including the full confidence interval. It is part of the core NBenchmark package with no additional dependencies.

CSV output is well-suited for post-processing in spreadsheets, Python/pandas, R, or any tool that can read delimited data.

Setup

using NBenchmark.Reporters;

// Default path
.WithReporter(new CsvReporter())

// Explicit path
.WithReporter(new CsvReporter("results/benchmark.csv"))

The default path is benchmark-results.csv in the current working directory.

Output format

Name,Median,Mean,StdDev,StdErr,MarginOfError,CiLower,CiUpper,ConfidenceLevel,CoefficientOfVariation,P95,P99,Ratio,Significant,AllocPerOp
"Compute",300.0,275.3,85.9,6.1,16.2,259.1,291.5,0.95,0.3122,500.0,500.0,0.75,"true",null
"Baseline",400.0,375.8,114.3,8.1,21.6,354.2,397.4,0.95,0.3043,500.0,900.0,1.00,"",null

All timing values are in nanoseconds.

Column reference

Column	Type	Description
Name	string	Benchmark name (double-quote escaped).
Median	float	Median timing in nanoseconds.
Mean	float	Arithmetic mean in nanoseconds.
StdDev	float	Sample standard deviation in nanoseconds.
StdErr	float	Standard error of the mean (StdDev / √n) in nanoseconds.
MarginOfError	float	Half-width of the confidence interval in nanoseconds.
CiLower	float	Lower bound of the confidence interval on the mean (Mean - MarginOfError).
CiUpper	float	Upper bound of the confidence interval on the mean (Mean + MarginOfError).
ConfidenceLevel	float	The confidence level used (e.g. 0.95).
CoefficientOfVariation	float	StdDev / Mean. Dimensionless measure of relative variability.
P95	float	95th percentile in nanoseconds.
P99	float	99th percentile in nanoseconds.
Ratio	float or null	Speed relative to the baseline. null if no baseline or only one benchmark.
Significant	"true" / "false" / empty	Mann-Whitney U significance result. Empty for the baseline or when significance testing is disabled.
AllocPerOp	integer or null	Mean heap bytes per iteration. null if allocation tracking is disabled.

Notes

• Results are sorted by median (fastest first).
• The output directory must already exist. CsvReporter does not create it.
• Names containing double-quotes are escaped by doubling the quote character (standard CSV escaping).

Using with Benchmark (Quick mode)

var result = Benchmark.Run(() => MyMethod());
await result.ToCsvAsync("results.csv");

CLI usage (BenchmarkHost)

dotnet run -- --reporter csv
dotnet run -- --reporter csv --output ./results

When --output is specified, the file is written as benchmark-results.csv inside that directory.