Add stats reporting for sidecar and telemetry

[bwoebi]

# DD_TRACE_CLI_ENABLED=1 php -d datadog.trace.log_level=trace -d datadog.trace.log_file=/tmp/sidelog -r 'var_dump(dd_trace_internal_fn("stats_sidecar"));'

outputs:

string(979) "{"trace_flusher":{"agent_config_allocated_shm":0,"agent_config_writers":0,"agent_configs_last_used_entries":0,"send_data_size":0},"sessions":5,"session_counter_size":5,"runtimes":4,"apps":4,"active_apps":0,"enqueued_apps":0,"enqueued_telemetry_data":{"dependencies_stored":0,"dependencies_unflushed":0,"configurations_stored":0,"configurations_unflushed":0,"integrations_stored":0,"integrations_unflushed":0,"metrics":0,"points":0,"actions":0,"computed_dependencies":0},"telemetry_metrics_contexts":4,"telemetry_worker":{"dependencies_stored":660,"dependencies_unflushed":660,"configurations_stored":832,"configurations_unflushed":0,"integrations_stored":10,"integrations_unflushed":10,"logs":0,"metric_contexts":4,"metric_buckets":{"buckets":8,"series":0,"series_points":0,"distributions":0,"distributions_points":0}},"telemetry_worker_errors":0,"log_writer":{"elements":2,"live_counters":2,"pending_removal":0},"log_filter":{"elements":2,"live_counters":2,"pending_removal":0}}"

Giving clear helpful debugging information for sidecar memory leaks. (upstream PR DataDog/libdatadog#392)

[codecov-commenter]

Codecov Report

Merging #2621 (7232505) into master (e721e34) will decrease coverage by 0.02%.
Report is 2 commits behind head on master.
The diff coverage is 16.66%.

Additional details and impacted files

@@             Coverage Diff              @@
##             master    #2621      +/-   ##
============================================
- Coverage     77.64%   77.62%   -0.02%     
  Complexity     2226     2226              
============================================
  Files           226      226              
  Lines         25942    25948       +6     
  Branches        986      986              
============================================
+ Hits          20142    20143       +1     
- Misses         5274     5279       +5     
  Partials        526      526              

Flag	Coverage Δ
appsec-extension	69.00% <ø> (ø)
tracer-extension	78.51% <16.66%> (-0.03%)	⬇️
tracer-php	80.16% <ø> (ø)

Flags with carried forward coverage won't be shown. Click here to find out more.

Files	Coverage Δ
ext/ddtrace.c	73.55% <16.66%> (-0.25%)	⬇️

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[pr-commenter]

Benchmarks

Benchmark execution time: 2024-04-15 15:06:47

Comparing candidate commit 7232505 in PR branch bob/sidecar-stats with baseline commit e721e34 in branch master.

Found 5 performance improvements and 3 performance regressions! Performance is the same for 170 metrics, 0 unstable metrics.

scenario:MessagePackSerializationBench/benchMessagePackSerialization

• 🟩 execution_time [-10.014µs; -8.626µs] or [-6.400%; -5.512%]

scenario:MessagePackSerializationBench/benchMessagePackSerialization-opcache

• 🟩 execution_time [-12.076µs; -9.304µs] or [-7.540%; -5.809%]

scenario:PDOBench/benchPDOBaseline

• 🟥 execution_time [+15.082µs; +15.884µs] or [+8.742%; +9.207%]

scenario:PDOBench/benchPDOBaseline-opcache

• 🟩 execution_time [-17.616µs; -13.280µs] or [-9.357%; -7.054%]

scenario:PDOBench/benchPDOOverhead

• 🟥 execution_time [+5.192µs; +13.055µs] or [+3.015%; +7.581%]

scenario:PDOBench/benchPDOOverhead-opcache

• 🟩 execution_time [-16.084µs; -12.472µs] or [-8.601%; -6.670%]

scenario:PDOBench/benchPDOOverheadWithDBM-opcache

• 🟩 execution_time [-15.943µs; -15.077µs] or [-8.420%; -7.963%]

scenario:TraceSerializationBench/benchSerializeTrace

• 🟥 execution_time [+12.752µs; +16.948µs] or [+7.065%; +9.390%]