lib: cmetrics: upgrade to v2.2.1

Signed-off-by: Eduardo Silva <eduardo@chronosphere.io>

Author: edsiper

lib/cmetrics/.github/workflows/build.yaml

@@ -59,15 +59,12 @@ jobs:
           provenance: false
 
   build-debian:
-    name: Debian Buster build to confirm no issues once used downstream
+    name: Debian Bookworm build to confirm no issues once used downstream
     runs-on: ubuntu-latest
-    container: debian:buster
+    container: debian:bookworm
     steps:
       - name: Set up base image dependencies
         run: |
-          # Update sources to use archive.debian.org (Buster reached end-of-life)
-          sed -i 's/deb.debian.org/archive.debian.org/g' /etc/apt/sources.list
-          sed -i 's/security.debian.org/archive.debian.org/g' /etc/apt/sources.list
           apt-get update
           apt-get install -y build-essential wget make gcc g++ git libcurl4-openssl-dev
 

lib/cmetrics/AGENTS.md

@@ -0,0 +1,12 @@
+## Testing
+
+- When making code changes, run the related unit test when one is available.
+
+## Performance
+
+- Build benchmarks with `CMT_BENCHMARKS=ON` and an optimized Release build.
+- For performance changes, capture at least five before and five after runs on
+  the same machine with identical compiler flags and workload parameters.
+- Use `benchmarks/run-perf.sh` for the standard workloads and Linux `perf stat`
+  hardware counters. Keep only changes with repeatable improvements and no
+  relevant benchmark regressions.

lib/cmetrics/CMakeLists.txt

@@ -63,17 +63,14 @@ if(NOT MSVC)
   set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -Wall")
 endif()
 
-# Define __CMT_FILENAME__ consistently across Operating Systems
-if(NOT ${CMAKE_SYSTEM_NAME} MATCHES "Windows")
-  set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -D__CMT_FILENAME__='\"$$(subst ${CMAKE_SOURCE_DIR}/,,$$(abspath $$<))\"'")
-else()
-  set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -D__CMT_FILENAME__=__FILE__")
-endif()
+# Define __CMT_FILENAME__
+set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -D__CMT_FILENAME__=__FILE__")
 
 # Configuration options
 option(CMT_DEV                       "Enable development mode"                    No)
 option(CMT_DEBUG                     "Enable debug mode"                          No)
 option(CMT_TESTS                     "Enable unit testing"                        No)
+option(CMT_BENCHMARKS                "Build performance benchmarks"               No)
 option(CMT_INSTALL_TARGETS           "Enable subdirectory library installations" Yes)
 option(CMT_PROMETHEUS_TEXT_DECODER   "Enable prometheus text format decoder (requires Flex/Bison)" Yes)
 
@@ -302,6 +299,10 @@ endif()
 add_subdirectory(include)
 add_subdirectory(src)
 
+if(CMT_BENCHMARKS)
+  add_subdirectory(benchmarks)
+endif()
+
 # Tests
 if(CMT_TESTS)
   enable_testing()

lib/cmetrics/README.md

@@ -141,6 +141,10 @@ CMetrics is heavily inspired by the Go Prometheus Client API design:
 
 - https://pkg.go.dev/github.com/prometheus/client_golang/prometheus#section-documentation
 
+Additional design notes:
+
+- [Long metric label handling](docs/label-value-handling.md)
+
 ## License
 
 This program is under the terms of the

lib/cmetrics/benchmarks/CMakeLists.txt

@@ -0,0 +1,6 @@
+add_executable(cmt-benchmark benchmark.c)
+target_link_libraries(cmt-benchmark cmetrics-static cfl-static fluent-otel-proto)
+
+if(NOT CMT_SYSTEM_WINDOWS)
+  target_link_libraries(cmt-benchmark pthread)
+endif()

lib/cmetrics/benchmarks/README.md

@@ -0,0 +1,38 @@
+# CMetrics benchmarks
+
+Benchmarks are opt-in and are intended for before/after comparisons on the
+same machine. Build an optimized binary:
+
+```sh
+cmake -S . -B build-perf \
+    -DCMT_BENCHMARKS=ON \
+    -DCMT_INSTALL_TARGETS=OFF \
+    -DCMAKE_BUILD_TYPE=Release \
+    -DCMAKE_C_FLAGS_RELEASE='-O3 -DNDEBUG'
+cmake --build build-perf -j --target cmt-benchmark
+```
+
+Run the standard repeated workloads and Linux hardware counters:
+
+```sh
+REPETITIONS=5 benchmarks/run-perf.sh \
+    ./build-perf/benchmarks/cmt-benchmark
+```
+
+The executable also accepts individual workloads:
+
+```text
+cmt-benchmark lookup|update|prometheus|opentelemetry|opentelemetry-mixed CARDINALITY OPERATIONS
+```
+
+The `opentelemetry` workload repeatedly encodes a labeled counter with the
+requested number of series. The `opentelemetry-mixed` workload creates that
+many counter, gauge, and histogram series to exercise scalar and aggregate
+protobuf data points in the same request.
+
+Compare medians from at least five alternating before/after runs. Keep CPU
+frequency policy, compiler, flags, machine load, and input parameters fixed.
+Use the reported in-process `elapsed_ns` for the operation itself and `perf
+stat` for whole-process hardware counters. Whole-process counters include
+series construction and teardown by design, exposing setup complexity as well
+as steady-state behavior.