latreport

The latreport command generates latency reports from binary latency files produced by StatsLatencyWriter. It reads the binary data, computes percentile breakdowns per sample bucket, and writes the results to CSV or Excel format.

Usage

rumi tools latreport [options]

Options

Option	Description
-h, --help	Show help message
-f, --inputfile <file>	(Required) Path to the input binary latency file
-o, --outputfile <file>	Output file path (default: same directory and base name as input file)
-t, --title <title>	Report title (default: output file base name)
-w, --warmup <count>	Number of initial data points to skip as warmup
-m, --maxval <value>	Violation threshold value. Data points exceeding this value are counted as violations
-s, --samplesize <size>	Number of data points per sample bucket
-c, --cfg <file>	Path to an XML configuration file for advanced settings
--bucketcnt <count>	Number of frequency map buckets for histogram generation
--stddev	Enable standard deviation calculation
--processors <count>	Number of reader threads for parallel processing
--writepoint <value>	Write point interval for filtering write-induced latency spikes
--prewritewarmup <count>	Number of data points to exclude before each write point
--postwritewarmup <count>	Number of data points to exclude after each write point
--format <csv|xlsx>	Output format (default: csv)

Examples

Basic Report

Generate a CSV report from a latency file:

rumi tools latreport -f /path/to/test.latency

Output:

Generating latency report from: /path/to/test.latency
Latency report generated: /path/to/test.csv

The output file is created in the same directory as the input file, with the same base name and a .csv extension.

Custom Output File

Specify an output file path:

rumi tools latreport -f /path/to/test.latency -o /path/to/report

The appropriate extension (.csv or .xlsx) is appended automatically.

With Warmup and Sample Size

Skip the first 100,000 data points as warmup and use 10,000-point sample buckets:

rumi tools latreport -f /path/to/test.latency \
  -w 100000 \
  -s 10000 \
  -t "Performance Test Report"

Excel Output

Generate an Excel report with charts and histograms:

rumi tools latreport -f /path/to/test.latency --format xlsx

Write Point Filtering

When the application under test performs periodic writes (e.g., every 1,000,000 messages), the latency around the write point is typically elevated. Use --writepoint, --prewritewarmup, and --postwritewarmup to exclude these data points from the report:

rumi tools latreport -f /path/to/test.latency \
  --writepoint 1000000 \
  --prewritewarmup 1000 \
  --postwritewarmup 500

CSV Output Format

The CSV output contains one header row followed by one row per sample bucket. Each row includes:

Column	Description
Title	Sample bucket identifier (start row - end row)
Mean	Average latency for the bucket
StdDev	Standard deviation (if enabled)
50thP	50th percentile (median)
75thP	75th percentile
90thP	90th percentile
99thP	99th percentile
99.9thP	99.9th percentile
99.99thP	99.99th percentile
99.999thP	99.999th percentile
99.9999thP	99.9999th percentile
Max	Maximum value in the bucket
NoViolations	Number of data points exceeding the violation threshold

Excel Output Format

The Excel output (--format xlsx) includes:

• Latencies sheet - Percentile data (same columns as CSV), run metadata, violation charts, and configurable scatter plots

• Histogram sheet - Latency frequency distribution with bar charts showing both linear and logarithmic scales

Configuration File

For advanced configuration, use the -c option to specify an XML configuration file. The configuration file controls default values for input processing, output formatting, and graph generation.

Key configuration sections:

Section	Description
Input.Sampling.SampleSize	Default sample bucket size
Input.Sampling.MaxDataPointValue	Default violation threshold
Input.Sampling.WarmupDataPoints	Default warmup count
Input.Reading.BufferSize	File read buffer size
Input.Reading.ReaderThreads	Default thread count for parallel processing
Output.Format	Default output format (csv or xlsx)
Output.Control.Buckets	Default frequency histogram bucket count
Output.Control.IncludeStdDev	Whether to calculate standard deviation by default
Output.Graphing.Graph	Graph definitions for Excel output

Command-line options override configuration file values.

Binary File Formats

The tool automatically detects the latency file format:

• V1 format - 8 bytes per entry (4-byte index + 4-byte latency value)

• V2 format - 4 bytes per entry (latency value only, index inferred from position)

See Also

• tools - Tools overview

• Engine Stats - Engine metrics and timing data