Redo diagrams with Mermaid

[xlamorlette-datadog]

Description

Replace two diagrams (one in dot and one photo of a drawing) by Mermaid diagrams.

Motivation

Mermaid diagrams are much lighter in the code, and much easier to modify if necessary.

Additional Notes

Jira ticket: IDMPL-549 C++ Tracer: update and improve architecture documentation

[pr-commenter]

Benchmarks

Benchmark execution time: 2026-07-03 09:11:21

Comparing candidate commit e2c7657 in PR branch xlamorlette/redo-diagrams-in-documentation with baseline commit 9aa0079 in branch main.

Found 0 performance improvements and 0 performance regressions! Performance is the same for 8 metrics, 0 unstable metrics.

Explanation

This is an A/B test comparing a candidate commit's performance against that of a baseline commit. Performance changes are noted in the tables below as:

• 🟩 = significantly better candidate vs. baseline
• 🟥 = significantly worse candidate vs. baseline

We compute a confidence interval (CI) over the relative difference of means between metrics from the candidate and baseline commits, considering the baseline as the reference.

If the CI is entirely outside the configured SIGNIFICANT_IMPACT_THRESHOLD (or the deprecated UNCONFIDENCE_THRESHOLD), the change is considered significant.

Feel free to reach out to #apm-benchmarking-platform on Slack if you have any questions.

More details about the CI and significant changes

You can imagine this CI as a range of values that is likely to contain the true difference of means between the candidate and baseline commits.

CIs of the difference of means are often centered around 0%, because often changes are not that big:

---------------------------------(------|---^--------)-------------------------------->
                              -0.6%    0%  0.3%     +1.2%
                                 |          |        |
         lower bound of the CI --'          |        |
sample mean (center of the CI) -------------'        |
         upper bound of the CI ----------------------'

As described above, a change is considered significant if the CI is entirely outside the configured SIGNIFICANT_IMPACT_THRESHOLD (or the deprecated UNCONFIDENCE_THRESHOLD).

For instance, for an execution time metric, this confidence interval indicates a significantly worse performance:

----------------------------------------|---------|---(---------^---------)---------->
                                       0%        1%  1.3%      2.2%      3.1%
                                                  |   |         |         |
       significant impact threshold --------------'   |         |         |
                      lower bound of CI --------------'         |         |
       sample mean (center of the CI) --------------------------'         |
                      upper bound of CI ----------------------------------'

[datadog-prod-us1-3]

🎯 Code Coverage (details)
• Patch Coverage: 100.00%
• Overall Coverage: 91.66% (+0.00%)

_{This comment will be updated automatically if new data arrives.
🔗 Commit SHA: e2c7657 | Docs | Datadog PR Page | Give us feedback!}

[zacharycmontoya]

I'm a little confused by your naming. What do you think of the following suggestion? We could apply this similarly to the other segment as well if you think it makes sense.

Suggested change

	space:3 d["Service X - Trace segment 1"]:6 space:2
	space:4 e["X - segment 1"] f["X - segment 1"]:4 space:2
	space:3 d["Service X - Trace segment 1 - span s"]:6 space:2
	space:4 e["Service X - Trace segment 1 - child span s1"] f["Service X - Trace segment 1 - child span s2"]:4 space:2

[zacharycmontoya]

LGTM with a small non-blocking comment