echo: Reduce memory allocation by AnuthaDev · Pull Request #10090 · uutils/coreutils

AnuthaDev · 2026-01-06T19:26:21Z

Replaced the vector allocation in filter_flags with direct iterator usage for reduced memory overhead.

Added new tests to cover edge cases encountered during previous implementation attempts.

Memory Usage Analysis:

Using /usr/bin/time (Linux)

Create a test input file: printf "00 %.0s" {1..100000} > args.txt
Run the binary:

 /usr/bin/time -v ./target/release/coreutils echo $(cat args.txt)

Results:

main: Maximum resident set size (kbytes): 19364
This PR: Maximum resident set size (kbytes): 12280
System echo: Maximum resident set size (kbytes): 2544

Using dhat-rs:

main:

./target/release/coreutils echo $(cat args.txt) > /dev/null

dhat: Total:     10,065,406 bytes in 200,206 blocks
dhat: At t-gmax: 7,647,027 bytes in 200,135 blocks
dhat: At t-end:  2,648,051 bytes in 100,134 blocks

This PR:

./target/release/coreutils echo $(cat args.txt) > /dev/null

dhat: Total:     5,264,197 bytes in 200,188 blocks
dhat: At t-gmax: 5,000,140 bytes in 100,005 blocks
dhat: At t-end:  2,648,047 bytes in 100,134 blocks

ChrisDryden · 2026-01-06T19:35:04Z

This is great work, I'd love to see if we had a way to track these changes over time. What was the main method you used for determining the memory usage, did you set up a benchmark?

github-actions · 2026-01-06T19:40:56Z

GNU testsuite comparison:

Congrats! The gnu test tests/shuf/shuf-reservoir is no longer failing!
Congrats! The gnu test tests/sort/sort-stale-thread-mem is no longer failing!

github-actions · 2026-01-06T19:53:59Z

GNU testsuite comparison:

Congrats! The gnu test tests/shuf/shuf-reservoir is no longer failing!
Congrats! The gnu test tests/sort/sort-stale-thread-mem is no longer failing!

github-actions · 2026-01-06T20:41:50Z

GNU testsuite comparison:

Congrats! The gnu test tests/shuf/shuf-reservoir is no longer failing!
Congrats! The gnu test tests/sort/sort-stale-thread-mem is no longer failing!

codspeed-hq · 2026-01-06T20:43:13Z

CodSpeed Performance Report

Merging this PR will not alter performance

_{Comparing AnuthaDev:echo-alloc (db22117) with main (b804ca4)}

Summary

✅ 140 untouched benchmarks
⏩ 37 skipped benchmarks¹

37 benchmarks were skipped, so the baseline results were used instead. If they were deleted from the codebase, click here and archive them to remove them from the performance reports. ↩

AnuthaDev · 2026-01-06T20:45:33Z

Hey @ChrisDryden , for benchmarking I used /usr/bin/time in the beginning and later shifted to dhat.

I believe the dhat crate can be used in a CI pipeline to keep track of memory allocation changes over time.

sylvestre · 2026-01-07T05:45:40Z

@@ -523,12 +528,30 @@ fn full_version_argument() {
        .stdout_matches(&Regex::new(r"^echo \(uutils coreutils\) (\d+\.\d+\.\d+)\n$").unwrap());
 }

+#[test]


seems unrelated to this pr ?!

This PR removes the length check from args in case of --help and --version and instead uses other logic to infer the length

These test cases serve as additional confirmation that the changes did not regress any behaviour.

it makes our life harder as reviewers
and given your current stack of patches:

we will have to squash it and it won't be only for memory usage anymore

so, yeah, splitting it or writing a nice stack of patches would be appreciated

Improved the patchset. Please let me know if any further improvements are required.

sylvestre · 2026-01-07T05:45:51Z

 #[test]
 fn full_help_argument() {
    assert_ne!(new_ucmd!().arg("--help").succeeds().stdout(), b"--help\n");
    assert_ne!(new_ucmd!().arg("--help").succeeds().stdout(), b"--help"); // This one is just in case.
 }

+#[test]
+fn multiple_help_argument() {


same, unrelated

github-actions · 2026-01-07T14:49:08Z

GNU testsuite comparison:

Skipping an intermittent issue tests/timeout/timeout (passes in this run but fails in the 'main' branch)

AnuthaDev · 2026-01-07T19:05:16Z

The CI failure logs seem to indicate its unrelated to the PR changes? It was working with the same code earlier...

sylvestre reviewed Jan 7, 2026

View reviewed changes

AnuthaDev added 2 commits January 7, 2026 19:47

echo: Reduce memory allocation

2480e72

echo: Add more tests

db22117

AnuthaDev force-pushed the echo-alloc branch from c16c85e to db22117 Compare January 7, 2026 14:19

sylvestre merged commit 478daa1 into uutils:main Jan 8, 2026
131 of 132 checks passed

moonfruit mentioned this pull request Feb 3, 2026

uutils-selected 0.6.0 moonfruit/homebrew-tap#453

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Memory Usage Analysis:

Using /usr/bin/time (Linux)

Using dhat-rs:

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CodSpeed Performance Report

Merging this PR will not alter performance

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AnuthaDev commented Jan 6, 2026 •

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