Track peak memory usage in root span metrics

[bwoebi]

Fixes #2832.

Adding php.memory.peak_usage_bytes and php.memory.peak_real_usage_bytes metrics.

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 78.49%. Comparing base (735db41) to head (56a99ab). Report is 3 commits behind head on master.

Additional details and impacted files

[](https://app.codecov.io/gh/DataDog/dd-trace-php/pull/2840?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=DataDog) ```diff @@ Coverage Diff @@ ## master #2840 +/- ## ============================================ - Coverage 81.10% 78.49% -2.62% Complexity 2516 2516 ============================================ Files 146 173 +27 Lines 14651 18680 +4029 Branches 0 975 +975 ============================================ + Hits 11883 14662 +2779 - Misses 2768 3481 +713 - Partials 0 537 +537 ``` | [Flag](https://app.codecov.io/gh/DataDog/dd-trace-php/pull/2840/flags?src=pr&el=flags&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=DataDog) | Coverage Δ | | |---|---|---| | [appsec-extension](https://app.codecov.io/gh/DataDog/dd-trace-php/pull/2840/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=DataDog) | `69.12% <ø> (?)` | | | [tracer-extension](https://app.codecov.io/gh/DataDog/dd-trace-php/pull/2840/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=DataDog) | `78.17% <ø> (ø)` | | | [tracer-php](https://app.codecov.io/gh/DataDog/dd-trace-php/pull/2840/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=DataDog) | `82.27% <ø> (-0.06%)` | :arrow_down: | Flags with carried forward coverage won't be shown. [Click here](https://docs.codecov.io/docs/carryforward-flags?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=DataDog#carryforward-flags-in-the-pull-request-comment) to find out more. [see 28 files with indirect coverage changes](https://app.codecov.io/gh/DataDog/dd-trace-php/pull/2840/indirect-changes?src=pr&el=tree-more&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=DataDog) ------ [Continue to review full report in Codecov by Sentry](https://app.codecov.io/gh/DataDog/dd-trace-php/pull/2840?dropdown=coverage&src=pr&el=continue&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=DataDog). > **Legend** - [Click here to learn more](https://docs.codecov.io/docs/codecov-delta?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=DataDog) > `Δ = absolute (impact)`, `ø = not affected`, `? = missing data` > Powered by [Codecov](https://app.codecov.io/gh/DataDog/dd-trace-php/pull/2840?dropdown=coverage&src=pr&el=footer&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=DataDog). Last update [735db41...56a99ab](https://app.codecov.io/gh/DataDog/dd-trace-php/pull/2840?dropdown=coverage&src=pr&el=lastupdated&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=DataDog). Read the [comment docs](https://docs.codecov.io/docs/pull-request-comments?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=DataDog).

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Benchmarks

Benchmark execution time: 2024-09-06 13:20:51

Comparing candidate commit 56a99ab4ab2ddc69ad1996e59cc170d71859e231 in PR branch bob/peak_mem with baseline commit 735db41484d6c1d5e1d8d20035eb35c919f50938 in branch master.

Found 4 performance improvements and 4 performance regressions! Performance is the same for 170 metrics, 0 unstable metrics.

scenario:ComposerTelemetryBench/benchTelemetryParsing-opcache

• 🟥 execution_time [+1.147µs; +3.253µs] or [+2.139%; +6.070%]

scenario:ContextPropagationBench/benchExtractHeaders128Bit-opcache

• 🟩 execution_time [-60.041ns; -27.959ns] or [-5.668%; -2.639%]

scenario:MessagePackSerializationBench/benchMessagePackSerialization

• 🟩 execution_time [-12.195µs; -9.665µs] or [-7.776%; -6.163%]

scenario:MessagePackSerializationBench/benchMessagePackSerialization-opcache

• 🟩 execution_time [-11.541µs; -7.459µs] or [-7.422%; -4.797%]

scenario:PDOBench/benchPDOBaseline-opcache

• 🟥 execution_time [+15.357µs; +18.117µs] or [+9.145%; +10.789%]

scenario:PDOBench/benchPDOOverhead-opcache

• 🟥 execution_time [+14.021µs; +17.491µs] or [+5.182%; +6.464%]

scenario:PDOBench/benchPDOOverheadWithDBM-opcache

• 🟥 execution_time [+16.877µs; +19.368µs] or [+5.506%; +6.319%]

scenario:WordPressBench/benchWordPressOverhead

• 🟩 execution_time [-21.516ms; -21.399ms] or [-83.492%; -83.042%]