chore: Tests for mtu using Linux namespaces#3334
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larseggert wants to merge 7 commits intomozilla:mainfrom
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chore: Tests for mtu using Linux namespaces#3334larseggert wants to merge 7 commits intomozilla:mainfrom
mtu using Linux namespaces#3334larseggert wants to merge 7 commits intomozilla:mainfrom
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larseggert
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mxinden
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Pull request overview
This PR adds comprehensive MTU detection tests for Linux using network namespaces, enabling testing of complex networking scenarios that require root privileges.
Changes:
- Adds a new test file
mtu/tests/netns.rswith network namespace-based MTU detection tests - Extends CI pipeline to run these tests with elevated privileges on Ubuntu
- Tests cover various scenarios: custom MTUs, jumbo frames, multiple interfaces, loopback, and policy routing
Reviewed changes
Copilot reviewed 2 out of 2 changed files in this pull request and generated 2 comments.
| File | Description |
|---|---|
| mtu/tests/netns.rs | Implements network namespace test infrastructure and MTU detection test cases for Linux |
| .github/workflows/check-mtu.yml | Adds CI job to run network namespace tests with sudo privileges |
Merging this PR will degrade performance by 26.76%
Performance Changes
Comparing 
Footnotes
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Codecov Report✅ All modified and coverable lines are covered by tests. Additional details and impacted files@@ Coverage Diff @@
## main #3334 +/- ##
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- Coverage 94.26% 94.16% -0.10%
==========================================
Files 125 129 +4
Lines 37973 38338 +365
Branches 37973 38338 +365
==========================================
+ Hits 35795 36101 +306
- Misses 1339 1388 +49
- Partials 839 849 +10
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mxinden
reviewed
Feb 27, 2026
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| // Route in table 100 via VPN interface. |
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Doesn't our implementation always use RT_TABLE_MAIN? Would it find routes in table 100?
Line 122 in 26711da
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That field doesn't matter unless we also give it RTM_F_LOOKUP_TABLE, in which case the output would be filtered to the given table. (The test checks exactly that, two routes with different MTUs in different tables + policy routing.)
Would it be clearer if we used RT_TABLE_UNSPEC in the code?
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Failed Interop TestsQUIC Interop Runner, client vs. server, differences relative to
All resultsSucceeded Interop TestsQUIC Interop Runner, client vs. server neqo-pr as client
neqo-pr as server
Unsupported Interop TestsQUIC Interop Runner, client vs. server neqo-pr as client
neqo-pr as server
|
Contributor
Benchmark resultsSignificant performance differences relative to 26711da. transfer/1-conn/10_000-parallel-1b-resp (aka. RPS)/mtu-1504: 💔 Performance has regressed by +2.2959%. time: [282.57 ms 284.43 ms 286.28 ms]
thrpt: [34.931 Kelem/s 35.158 Kelem/s 35.389 Kelem/s]
change:
time: [+1.3009% +2.2959% +3.3470] (p = 0.00 < 0.05)
thrpt: [-3.2386% -2.2444% -1.2842]
Performance has regressed.All resultstransfer/1-conn/1-100mb-resp (aka. Download)/mtu-1504: Change within noise threshold. time: [199.43 ms 199.81 ms 200.23 ms]
thrpt: [499.42 MiB/s 500.48 MiB/s 501.43 MiB/s]
change:
time: [-0.9418% -0.5196% -0.1758] (p = 0.00 < 0.05)
thrpt: [+0.1761% +0.5224% +0.9507]
Change within noise threshold.
Found 4 outliers among 100 measurements (4.00%)
3 (3.00%) high mild
1 (1.00%) high severetransfer/1-conn/10_000-parallel-1b-resp (aka. RPS)/mtu-1504: 💔 Performance has regressed by +2.2959%. time: [282.57 ms 284.43 ms 286.28 ms]
thrpt: [34.931 Kelem/s 35.158 Kelem/s 35.389 Kelem/s]
change:
time: [+1.3009% +2.2959% +3.3470] (p = 0.00 < 0.05)
thrpt: [-3.2386% -2.2444% -1.2842]
Performance has regressed.transfer/1-conn/1-1b-resp (aka. HPS)/mtu-1504: No change in performance detected. time: [38.556 ms 38.726 ms 38.914 ms]
thrpt: [25.698 B/s 25.822 B/s 25.936 B/s]
change:
time: [-1.3804% -0.6442% +0.0993] (p = 0.08 > 0.05)
thrpt: [-0.0992% +0.6484% +1.3998]
No change in performance detected.
Found 9 outliers among 100 measurements (9.00%)
2 (2.00%) high mild
7 (7.00%) high severetransfer/1-conn/1-100mb-req (aka. Upload)/mtu-1504: Change within noise threshold. time: [204.00 ms 204.37 ms 204.78 ms]
thrpt: [488.34 MiB/s 489.31 MiB/s 490.19 MiB/s]
change:
time: [+0.2101% +0.4653% +0.7318] (p = 0.00 < 0.05)
thrpt: [-0.7265% -0.4632% -0.2097]
Change within noise threshold.
Found 2 outliers among 100 measurements (2.00%)
1 (1.00%) high mild
1 (1.00%) high severedecode 4096 bytes, mask ff: No change in performance detected. time: [4.5185 µs 4.5299 µs 4.5426 µs]
change: [-0.0958% +0.4764% +1.1918] (p = 0.15 > 0.05)
No change in performance detected.
Found 5 outliers among 100 measurements (5.00%)
2 (2.00%) high mild
3 (3.00%) high severedecode 1048576 bytes, mask ff: No change in performance detected. time: [1.1572 ms 1.1591 ms 1.1609 ms]
change: [-0.5913% -0.1013% +0.3345] (p = 0.68 > 0.05)
No change in performance detected.
Found 12 outliers among 100 measurements (12.00%)
10 (10.00%) low severe
2 (2.00%) high milddecode 4096 bytes, mask 7f: No change in performance detected. time: [5.7916 µs 5.8009 µs 5.8110 µs]
change: [-0.1517% +0.1397% +0.4498] (p = 0.39 > 0.05)
No change in performance detected.
Found 5 outliers among 100 measurements (5.00%)
2 (2.00%) high mild
3 (3.00%) high severedecode 1048576 bytes, mask 7f: No change in performance detected. time: [1.4864 ms 1.4890 ms 1.4920 ms]
change: [-0.5096% -0.0492% +0.3427] (p = 0.83 > 0.05)
No change in performance detected.
Found 1 outliers among 100 measurements (1.00%)
1 (1.00%) high milddecode 4096 bytes, mask 3f: No change in performance detected. time: [5.5403 µs 5.5504 µs 5.5616 µs]
change: [-0.2254% +0.0465% +0.3195] (p = 0.75 > 0.05)
No change in performance detected.
Found 4 outliers among 100 measurements (4.00%)
2 (2.00%) high mild
2 (2.00%) high severedecode 1048576 bytes, mask 3f: No change in performance detected. time: [1.4145 ms 1.4169 ms 1.4194 ms]
change: [-0.2366% -0.0091% +0.2174] (p = 0.94 > 0.05)
No change in performance detected.
Found 1 outliers among 100 measurements (1.00%)
1 (1.00%) high mildstreams/simulated/1-streams/each-1000-bytes: No change in performance detected. time: [129.68 ms 129.68 ms 129.68 ms]
thrpt: [7.5303 KiB/s 7.5306 KiB/s 7.5308 KiB/s]
change:
time: [-0.0042% -0.0006% +0.0029] (p = 0.75 > 0.05)
thrpt: [-0.0029% +0.0006% +0.0042]
No change in performance detected.
Found 2 outliers among 100 measurements (2.00%)
2 (2.00%) high mildstreams/simulated/1000-streams/each-1-bytes: No change in performance detected. time: [2.5363 s 2.5366 s 2.5369 s]
thrpt: [394.18 B/s 394.22 B/s 394.27 B/s]
change:
time: [-0.0084% +0.0084% +0.0255] (p = 0.34 > 0.05)
thrpt: [-0.0255% -0.0084% +0.0084]
No change in performance detected.streams/simulated/1000-streams/each-1000-bytes: No change in performance detected. time: [6.5848 s 6.5931 s 6.6027 s]
thrpt: [147.90 KiB/s 148.12 KiB/s 148.31 KiB/s]
change:
time: [-0.3039% -0.0790% +0.1365] (p = 0.47 > 0.05)
thrpt: [-0.1363% +0.0791% +0.3048]
No change in performance detected.
Found 6 outliers among 100 measurements (6.00%)
1 (1.00%) high mild
5 (5.00%) high severestreams/walltime/1-streams/each-1000-bytes: No change in performance detected. time: [588.30 µs 590.18 µs 592.35 µs]
change: [-0.2876% +0.2560% +0.7982] (p = 0.36 > 0.05)
No change in performance detected.
Found 8 outliers among 100 measurements (8.00%)
1 (1.00%) high mild
7 (7.00%) high severestreams/walltime/1000-streams/each-1-bytes: No change in performance detected. time: [12.528 ms 12.567 ms 12.625 ms]
change: [-0.2700% +0.2646% +0.7930] (p = 0.38 > 0.05)
No change in performance detected.
Found 2 outliers among 100 measurements (2.00%)
1 (1.00%) high mild
1 (1.00%) high severestreams/walltime/1000-streams/each-1000-bytes: Change within noise threshold. time: [45.444 ms 45.487 ms 45.532 ms]
change: [-0.4150% -0.2606% -0.1168] (p = 0.00 < 0.05)
Change within noise threshold.
Found 1 outliers among 100 measurements (1.00%)
1 (1.00%) high severecoalesce_acked_from_zero 1+1 entries: No change in performance detected. time: [91.949 ns 92.253 ns 92.563 ns]
change: [-0.7885% -0.1905% +0.3182] (p = 0.51 > 0.05)
No change in performance detected.
Found 10 outliers among 100 measurements (10.00%)
6 (6.00%) high mild
4 (4.00%) high severecoalesce_acked_from_zero 3+1 entries: No change in performance detected. time: [109.82 ns 110.22 ns 110.63 ns]
change: [-0.6153% +0.0556% +0.6823] (p = 0.88 > 0.05)
No change in performance detected.
Found 17 outliers among 100 measurements (17.00%)
3 (3.00%) low mild
1 (1.00%) high mild
13 (13.00%) high severecoalesce_acked_from_zero 10+1 entries: No change in performance detected. time: [109.08 ns 109.42 ns 109.85 ns]
change: [-1.0757% -0.3440% +0.1797] (p = 0.35 > 0.05)
No change in performance detected.
Found 19 outliers among 100 measurements (19.00%)
6 (6.00%) low severe
5 (5.00%) low mild
2 (2.00%) high mild
6 (6.00%) high severecoalesce_acked_from_zero 1000+1 entries: No change in performance detected. time: [94.872 ns 95.056 ns 95.244 ns]
change: [-0.4210% +0.1215% +0.6939] (p = 0.67 > 0.05)
No change in performance detected.
Found 8 outliers among 100 measurements (8.00%)
6 (6.00%) high mild
2 (2.00%) high severeRxStreamOrderer::inbound_frame(): Change within noise threshold. time: [109.13 ms 109.26 ms 109.44 ms]
change: [-0.8620% -0.5546% -0.3048] (p = 0.00 < 0.05)
Change within noise threshold.
Found 15 outliers among 100 measurements (15.00%)
6 (6.00%) low mild
5 (5.00%) high mild
4 (4.00%) high severesent::Packets::take_ranges: No change in performance detected. time: [4.4791 µs 4.5730 µs 4.6590 µs]
change: [-3.4618% -0.2367% +3.0106] (p = 0.89 > 0.05)
No change in performance detected.
Found 1 outliers among 100 measurements (1.00%)
1 (1.00%) high mildtransfer/simulated/pacing-false/varying-seeds: No change in performance detected. time: [23.941 s 23.941 s 23.941 s]
thrpt: [171.09 KiB/s 171.09 KiB/s 171.09 KiB/s]
change:
time: [+0.0000% +0.0000% +0.0000] (p = NaN > 0.05)
thrpt: [+0.0000% +0.0000% +0.0000]
No change in performance detected.transfer/simulated/pacing-true/varying-seeds: No change in performance detected. time: [23.676 s 23.676 s 23.676 s]
thrpt: [173.01 KiB/s 173.01 KiB/s 173.01 KiB/s]
change:
time: [+0.0000% +0.0000% +0.0000] (p = NaN > 0.05)
thrpt: [+0.0000% +0.0000% +0.0000]
No change in performance detected.transfer/simulated/pacing-false/same-seed: No change in performance detected. time: [23.941 s 23.941 s 23.941 s]
thrpt: [171.09 KiB/s 171.09 KiB/s 171.09 KiB/s]
change:
time: [+0.0000% +0.0000% +0.0000] (p = NaN > 0.05)
thrpt: [+0.0000% +0.0000% +0.0000]
No change in performance detected.transfer/simulated/pacing-true/same-seed: No change in performance detected. time: [23.676 s 23.676 s 23.676 s]
thrpt: [173.01 KiB/s 173.01 KiB/s 173.01 KiB/s]
change:
time: [+0.0000% +0.0000% +0.0000] (p = NaN > 0.05)
thrpt: [+0.0000% +0.0000% +0.0000]
No change in performance detected.transfer/walltime/pacing-false/varying-seeds: Change within noise threshold. time: [23.066 ms 23.083 ms 23.101 ms]
change: [+0.2022% +0.3085% +0.4093] (p = 0.00 < 0.05)
Change within noise threshold.
Found 2 outliers among 100 measurements (2.00%)
2 (2.00%) high mildtransfer/walltime/pacing-true/varying-seeds: Change within noise threshold. time: [23.863 ms 23.877 ms 23.892 ms]
change: [+1.1994% +1.4055% +1.5614] (p = 0.00 < 0.05)
Change within noise threshold.transfer/walltime/pacing-false/same-seed: Change within noise threshold. time: [23.350 ms 23.367 ms 23.383 ms]
change: [+0.9077% +1.0735% +1.2111] (p = 0.00 < 0.05)
Change within noise threshold.
Found 8 outliers among 100 measurements (8.00%)
3 (3.00%) low mild
4 (4.00%) high mild
1 (1.00%) high severetransfer/walltime/pacing-true/same-seed: No change in performance detected. time: [23.652 ms 23.685 ms 23.733 ms]
change: [-0.3383% -0.1488% +0.0640] (p = 0.17 > 0.05)
No change in performance detected.
Found 3 outliers among 100 measurements (3.00%)
2 (2.00%) high mild
1 (1.00%) high severeDownload data for |
Contributor
Client/server transfer resultsPerformance differences relative to 26711da. Transfer of 33554432 bytes over loopback, min. 100 runs. All unit-less numbers are in milliseconds.
Table above only shows statistically significant changes. See all results below. All resultsTransfer of 33554432 bytes over loopback, min. 100 runs. All unit-less numbers are in milliseconds.
Download data for |
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