Decompression of level 17 frames

Recorded run: long-20261109 (2026-11-09). CSV · Environment · Methodology and limits.

Level belongs to the C encoder that prepared the frame; decoders have no level setting. Both decoders restore the same bytes.

Median speed across 8 datasets

Median of per-dataset C mean time / decoder mean time ratios, with equal weight. Higher is faster; 1× matches C. No confidence interval is inferred for this across-dataset median.

Decoder	Median speed / C
zstd C	1.000×
mzstd	1.348×

Decompression by dataset at source level 17

Datasets are ranked by mzstd speed relative to C, highest first. Throughput counts restored bytes; empty input has latency only. Whiskers and intervals describe sampling uncertainty, not all host variation. Cold APIs include allocation and disposal. C reads the frame’s content size and decodes into a buffer of exactly that size; mzstd returns its own vector.

empty

Empty input; measures API overhead.

9 compressed → 0 restored bytes; compressed / original: undefined.

Decoder	Mean µs	95% mean interval µs	Decoded MiB/s	Speed / C
zstd C	2.027	1.975–2.085	—	1.000×
mzstd	0.03771	0.03687–0.03869	—	53.745×

tiny-text

44-byte quick-brown-fox sentence.

53 compressed → 44 restored bytes; compressed / original: 120.455%.

Decoder	Mean µs	95% mean interval µs	Decoded MiB/s	Speed / C
zstd C	2.075	2.013–2.152	20.22	1.000×
mzstd	0.0517	0.05–0.05362	811.60	40.139×

random-64k

64 KiB prefix of the deterministic pseudorandom corpus.

65,546 compressed → 65,536 restored bytes; compressed / original: 100.015%.

Decoder	Mean µs	95% mean interval µs	Decoded MiB/s	Speed / C
zstd C	2.834	2.798–2.878	22,050.01	1.000×
mzstd	0.8997	0.8917–0.9091	69,463.76	3.150×

repeated-1m

1 MiB of repeated a bytes.

49 compressed → 1,048,576 restored bytes; compressed / original: 0.005%.

Decoder	Mean µs	95% mean interval µs	Decoded MiB/s	Speed / C
zstd C	14.86	14.43–15.33	67,299.09	1.000×
mzstd	9.948	9.674–10.23	100,520.54	1.494×

binary-64k

64 KiB of structured binary bytes: ((i / 16) XOR i) modulo 256.

1,259 compressed → 65,536 restored bytes; compressed / original: 1.921%.

Decoder	Mean µs	95% mean interval µs	Decoded MiB/s	Speed / C
zstd C	6.498	6.301–6.713	9,617.73	1.000×
mzstd	5.409	5.1–5.721	11,554.68	1.201×

random-1m

1 MiB of deterministic xorshift64 pseudorandom bytes.

1,048,609 compressed → 1,048,576 restored bytes; compressed / original: 100.003%.

Decoder	Mean µs	95% mean interval µs	Decoded MiB/s	Speed / C
zstd C	19.45	19.31–19.62	51,406.14	1.000×
mzstd	17.05	16.91–17.2	58,665.51	1.141×

text-1m

Alice text repeated cyclically to 1 MiB.

49,642 compressed → 1,048,576 restored bytes; compressed / original: 4.734%.

Decoder	Mean µs	95% mean interval µs	Decoded MiB/s	Speed / C
zstd C	119	114.7–124	8,403.13	1.000×
mzstd	126.9	122.8–131.6	7,882.11	0.938×

alice29

Alice in Wonderland text from the Canterbury corpus (testdata/alice29.txt).

49,341 compressed → 152,089 restored bytes; compressed / original: 32.442%.

Decoder	Mean µs	95% mean interval µs	Decoded MiB/s	Speed / C
zstd C	103.3	101.1–105.9	1,404.16	1.000×
mzstd	127.2	118.6–136.4	1,140.26	0.812×

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mzstd