v4.0.0

Changed

• All samplers are now async and run on-demand when a metrics endpoint is hit.
  Percentiles must now be calculated from the free-running histograms. (#334)
• BPF is now non-optional on Linux. (#336)
• Makes HTTP compression dependent on client accept headers, removes the need
  for separate configuration of compression. (#337)
• Removes histograms for counter and gauge metrics. (#338)
• Histogram grouping power reduced from 7 (0.781% error) to 3 (12.5% error).
  This reduces the memory footprint for each histogram. (#339)

Added

• Syscall samplers now track yield syscall. (#310)
• TCP active open (connect) latency now tracked. (#342)

v3.18.1

Changed

• Ubuntu Bionic dropped from packaging job. (#306)

v3.18.0

Fixed

• CPU per core cycle and instruction counters were incorrect. The system totals
  reflected the appropriate value. (#304)

Added

• Allow setting the metric snapshot interval to better address cases where
  metrics are not scraped on a secondly basis. (#286)
• Network carrier change metric. (#290)

Changed

• Explicitly use relaxed atomics in BPF samplers. (#276)
• Split syscall sampler into syscall_latency and syscall_counts to allow more
  fine-grained configuration and allow for reduced overhead. (#298)
• Split block_io latency sampler into block_io_latency and block_io_requests to
  allow more fine-grained configuration and allow for reduced overhead. (#299)

v3.17.0

Fixed

• Fixes sampler configuration inheritance for partially defined sampler config
  sections (#273)
• Linux BPF CPU usage sampler had idle time metric counting backwards (#281)

Added

• Fallback for linux network traffic sampler to get metrics from sysfs when BPF
  is not enabled or fails to initialize (#274)
• JSON stats endpoints (#277)

v3.16.0

Fixed

• Listen address could not be changed (#264)

Added

• CPU busy time metric for non-Prometheus endpoints (#256)

v3.15.0

Fixed

• CPU usage sampler could not be disabled (#259)
• Example config out-of-date (#260)

Added

• Example Grafana/Prometheus dashboard (#239)
• Off-CPU time added to the scheduler runqueue sampler (#240)
• Filesystem sampler added and tracks the number of open file descriptors (#242)
• Log level can now be set in the config (#246)
• Network interface statistics for tx/rx errors (drop, crc, ...) (#247)
• BPF can be enabled/disabled per-sampler or globally. (#258)

v3.14.2

Fixed

• CPU usage for soft and hard irq was incorrectly reported. (#236)

v3.14.1

Fixed

• CPU usage reporting via BPF would report CPU as always idle on some systems.
  (#233)

v3.14.0

Changed

• metriken crates updated which changes the msgpack output. (#224)

Fixed

• Dependency updates to address RUSTSEC-2024-0332.

v3.13.0

Changed

• Memory sampler was reporting memory usage stats in KiB, but with bytes for the
  unit metadata. This change corrects the sampler to report memory usage in
  bytes. This fix is disruptive as it will cause the memory stats to change.
  (#222)