Digest Benchmark - 2026-04-25

This benchmark compares Mercury mhash against common Windows and CLI hash tools on the same machine.

Method

Harness: scripts/benchmark-mhash.ps1
Scenario: warm-cache CLI hashing; Windows does not provide a safe non-admin cache-drop primitive, so cold-cache disk results are intentionally excluded.
Inputs: deterministic 1MiB, 64MiB, and 256MiB files under target\mhash-benchmark\data.
Algorithms: md5, sha1, sha256, sha512.
Repeats: 1 warmup plus 3 measured runs per tool/algorithm/size.
Metrics: wall-clock time, throughput, process CPU time as percent of one core, and peak working set.
Machine: DESKTOP-EKBHO4B, Windows 10.0.26200, 32 logical processors.

Tools

Mercury mhash 0.1.0
PowerShell Get-FileHash via PowerShell 7.6.1
Windows certutil
uutils coreutils 0.8.0 commands: md5sum, sha1sum, sha256sum, sha512sum
OpenSSL 3.6.1

Key Finding

The original Mercury mhash default auto mode memory-mapped large ordinary hash jobs. On this machine that increased peak working set to roughly the file size and was slower than streaming reads. The default was changed so streaming-friendly hash sets use one-pass buffered reads, while whole-file paths remain available for explicit --io mmap and for algorithms that benefit from whole-file/internal parallel processing.

256MiB Before/After

Algorithm	Before auto ms	After auto ms	Speedup	Before peak MiB	After peak MiB	Peak drop MiB
md5	427.06	362.24	1.18x	261.54	10.30	251.24
sha1	201.81	163.24	1.24x	255.72	10.55	245.17
sha256	226.63	156.31	1.45x	261.05	10.29	250.76
sha512	341.78	273.64	1.25x	264.60	10.57	254.03

256MiB Post-Optimization Comparison

Algorithm	Tool	Mean ms	MiB/s	Peak WS MiB	CPU % of one core
md5	openssl:dgst	353.02	725.17	12.17	100.5
md5	mercury-mhash:auto	362.24	706.71	10.30	94.9
md5	mercury-mhash:read	364.38	702.57	10.30	95.8
md5	coreutils:md5sum	377.49	678.17	9.44	96.6
md5	windows:certutil	521.46	490.93	14.71	91.9
md5	powershell:Get-FileHash	742.67	344.70	65.20	113.7
sha1	mercury-mhash:read	155.19	1649.56	10.54	90.6
sha1	coreutils:sha1sum	160.77	1592.36	9.45	90.7
sha1	mercury-mhash:auto	163.24	1568.23	10.55	98.9
sha1	openssl:dgst	196.64	1301.90	10.98	98.0
sha1	windows:certutil	398.24	642.82	14.73	99.4
sha1	powershell:Get-FileHash	641.07	399.33	66.26	114.5
sha256	mercury-mhash:read	155.78	1643.35	10.29	93.6
sha256	mercury-mhash:auto	156.31	1637.75	10.29	90.0
sha256	coreutils:sha256sum	170.32	1503.08	10.36	97.9
sha256	openssl:dgst	206.06	1242.36	10.99	91.0
sha256	windows:certutil	270.40	946.74	14.75	92.5
sha256	powershell:Get-FileHash	519.56	492.72	65.04	122.3
sha512	mercury-mhash:auto	273.64	935.52	10.57	99.0
sha512	mercury-mhash:read	273.88	934.70	10.31	93.2
sha512	openssl:dgst	277.36	922.98	10.99	99.5
sha512	coreutils:sha512sum	299.48	854.80	9.45	93.9
sha512	windows:certutil	910.10	281.29	14.73	99.6
sha512	powershell:Get-FileHash	1168.26	219.13	65.48	106.6

Reproduce

just mhash-benchmark

or:

pwsh -NoProfile -ExecutionPolicy Bypass -File .\scripts\benchmark-mhash.ps1

The harness writes raw JSON, summary JSON, CSV, and Markdown reports under target\mhash-benchmark\results.

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