Benchmarks

Every number on this page comes from a file in the repository. Each table names the machine, the system, the date, the command and the source.

The data is generated by rift-gen with seed 7, profile sql, with a mutation starting at about one line in a thousand (--change-ratio 0.001, the default). Rift runs at --mem 256M. Peak memory is the resident set. Peak heap is Rift's own counter, the part --mem limits.

The largest pair measured so far is 10 GiB. No pair above that has been run.

Apple M1, 1 GiB and 10 GiB

Hardware: Apple M1, 16 GB RAM, internal SSD.
System: macOS, warm page cache.
Date: not recorded in the README; the table entered the repository on 2026-11-05.
Commands: bench/run.sh prints the full results with the commands and seeds. bench/data.sh regenerates the data.
Source: the Benchmarks section of README.md at the v0.1.0 tag. The README no longer carries it.

Pair	Tool	Time	Peak memory
1 GiB	rift --summary	1.26 s	127.7 MiB
1 GiB	rift (full diff)	0.93 s	130.8 MiB
1 GiB	system diff	17.55 s	3.2 GiB
10 GiB	rift --summary	13.37 s	136.5 MiB
10 GiB	rift (full diff)	26.16 s	136.5 MiB
10 GiB	diff, git diff	did not run: needs more than 16 GB of RAM

git diff has no 1 GiB row: it treats files over 512 MiB as binary and prints no diff. On the 1 GiB pair Rift's heap peaked at 83.5 MiB, and on the 10 GiB pair at 94.1 MiB.

Intel Core i5-10600, 256 MiB to 2 GiB

Hardware: Intel Core i5-10600 (6 cores, 12 threads), 16 GB RAM, bare metal.
System: Ubuntu 26.04.1 LTS, Linux 7.0.0-42, files in tmpfs, so the run measures CPU, memory and the algorithm, not the disk.
Date: 2026-11-06.
Version: the run used Rift at the v0.1.0 tag.
Command: bench/linux-safe.sh. The runs were rift --stats --mem 256M a b, rift --summary --mem 256M a b, diff a b and git diff --no-index a b, plus --mem 64M and --mem 1G for the memory rows. Each time is the median of three runs.
Source: bench/results/linux-intel-core-i5-10600-2026-11-06/report.md and results.json, in the same directory.

Pair	Tool	Time	Peak memory	Peak heap
256 MiB	rift (full diff)	0.28 s	112.8 MiB	83.2 MiB
256 MiB	GNU diff	1.62 s	776.3 MiB
256 MiB	git diff --no-index	2.57 s	1.0 GiB
1 GiB	rift (full diff)	0.69 s	113.0 MiB	83.6 MiB
1 GiB	rift --summary	0.51 s	113.0 MiB	83.6 MiB
1 GiB	rift --mem 64M (full diff)	0.54 s	30.7 MiB	21.0 MiB
1 GiB	rift --mem 1G (full diff)	1.20 s	436.3 MiB	329.2 MiB
1 GiB	GNU diff	killed at the memory cap
1 GiB	git diff --no-index	42.59 s	5.3 MiB
2 GiB	rift (full diff)	1.20 s	113.4 MiB	83.6 MiB
2 GiB	rift --summary	0.86 s	113.0 MiB	83.6 MiB
2 GiB	rift --mem 64M (full diff)	1.02 s	30.5 MiB	21.0 MiB
2 GiB	rift --mem 1G (full diff)	1.75 s	436.8 MiB	330.0 MiB

GNU diff was capped at 3 GiB of memory, and the cap killed it on the 1 GiB pair. git diff --no-index finished that pair in about 42 s because it printed no diff: it treats the files as binary, and its output was 241 bytes.

The two extra rows for each size show what --mem does. On the 1 GiB pair, --mem 64M took a heap of 21.0 MiB and --mem 1G took 329.2 MiB. The full report, with the CSV pairs and the thread scaling, is in the file above.

What these numbers do not show

Disk speed on the Linux run: the files were in RAM.
Other tools than GNU diff and git diff.
A run above 10 GiB.
Different machines side by side. Compare the memory between the two tables, not the times.