s2n-tls — Engineering Performance
13 engineers all time · Jan 2025 – Sep 2026 · built 2026-09-10 · GitHub
Performance snapshot
Today's rolling 90-day reading for s2n-tls, compared with the start of the series. Pick a window to move that comparison point.
Avg. perf / dev / mo
+188.4%
0.21 → 0.60 ETV
Active engineers
−11.1%
9.0 → 8.0
Features
+2.8pp
25.1% → 27.9%
vs. AWS
0.72x
0.64x → 0.72x · −28% below
s2n-tls vs. AWS
Per-engineer ETV for s2n-tls against AWS as a whole. Both lines are 90-day rolling averages scaled to a 30-day month, so they share one axis and can be read against each other at any point. Pick a window to zoom the chart to it.
Performance Composition
Each month's output split by type of work: Features (new value), Maintenance (sustaining systems), Tests, Docs, and Fixes (rework). The yellow line is output per engineer, so when it rises each engineer is delivering more, whatever the team size did. Unit: Engineering Throughput Value (ETV).
Engineering capacity
Effective engineers behind s2n-tls, against its pre-AI baseline. Each subject has its own: s2n-tls's is 0.21 ETV / dev / mo, its first reading in Q1 2025. Per-engineer ETV divided by that gives a capacity multiple, and that multiple applied to the engineers active in the trailing 90 days turns it into engineer-equivalents. The line is the real headcount, so the gap between line and area is what the leverage is worth. Because each baseline is its own, every subject opens at 1.0x on its first day: multiples measure improvement and are not comparable between subjects.
Knowledge concentration
How dependent is this repo on a small number of engineers? Higher top-1 share = higher key-person risk.
James Mayclin owns 28.3 % of commits.
Behind the numbers
Written summary of the work completed each month.
No monthly reports available yet.
Most impactful commits
Top 10 by ETV in the all-time window.
- 2.8ETVtest: add test certs for cert intent validation (#5630)Carol Yeh · 67dc64e3 · 2025-12-02
- 1.6ETVrefactor(metrics-subscriber): key handshake counters by IANA id (#5858)kaukabrizvi · c9348948 · 2026-05-08
- 1.2ETVfeat(aws-kms-tls-auth): add provider & receiver structs (#5408)James Mayclin · 8619a264 · 2025-07-15
- 1.1ETVfeat(s2n-metric-subscriber): add supported parameters (#5768)James Mayclin · b0e48bd2 · 2026-03-17
- 1.0ETVfeat(metrics-schema): Seperate out schema serialization from s2n-tls-metrics-subscriber (#5877)Sean McGrail · 018d43d3 · 2026-06-03
- 1.0ETVrefactor(tls-harness): separate benchmark abstractions (#5444)James Mayclin · 418313c2 · 2025-07-31
- 0.9ETVrefactor: use header struct for decryption (#6004)James Mayclin · 627cfd18 · 2026-07-27
- 0.8ETVfeat: add async public key support (#5473)Carol Yeh · 792d3667 · 2025-09-12
- 0.8ETVfeat: add handshake event (#5635) Co-authored-by: maddeleine <59030281+maddeleine@users.noreply.github.com>James Mayclin · 60c23c2d · 2025-12-18
- 0.8ETVfeat(aws-kms-tls-auth): add codec and parsing (#5398)James Mayclin · dc99a174 · 2025-07-10