Performance & Tracing Update

High level summary

• Benchmarking: -O2 build optimization benchmarks.
• Development: Legacy iohk-monitoring tracing backend removed from cardano-node; RTView removed from cardano-tracer; trace-dispatcher maintenance and ongoing restructuring into Hermod packages.
• Infrastructure: Genesis cache overhaul with full Protocol Version 11 overlay close to merging.
• Tracing: ReCon framework and trace-resources moved to Hermod project; cardano-tracer timeseries HTTP API and Grafana datasource merged; ASCII operator spellings for cardano-recon-framework.

Low level overview

Benchmarking

The P&T team has performed benchmarks of a highly optimized build (-O2) vs. a build using standard optimization (-O1), the latter being the current default for our releases. The benchmarks demonstrated that under low to near-idle submission load, no significant gains in resource usage were achieved. Only under full saturation over extended periods of time was a ~17% reduction in Process CPU usage measured, whereas RAM usage was stable. However, in both cases, we observed small increases (3% - 6%) in block adoption times across the network. For the current Praos Node, we still recommend the default. When using another Consensus mode with a significantly higher idle baseline, it's worth noting there's a potential trade-off that can be made.

Development

Last month we reported that the removal of the legacy iohk-monitoring-based tracing backend from cardano-node was complete but awaiting final verification. That PR has now been merged (cardano-node PR#6580). The change eliminates approximately 11,000 lines of dead code across 15 modules and removes 9 transitive build dependencies, leaving trace-dispatcher as the sole tracing backend. With this out of the way, the remaining components of the new tracing system can be moved into the self-contained Hermod Tracing System project repository without coupling their release cycle to cardano-node. Please refer to the PR description for a detailed breakdown of now obsolete Node config keys.

Alongside that, RTView has been removed from cardano-tracer (cardano-node PR#6607). RTView was an experimental, opt-in browser dashboard hidden behind a build flag since version 0.2.4. Its functionality is now fully covered by the Grafana datasource and the timeseries server built into cardano-tracer, making the component redundant. The removal cleans up 35 source files and several build dependencies.

The P&T team has also completed a focused maintenance pass over trace-dispatcher (hermod-tracing PR#12). Additionally, work is underway to restructure trace-dispatcher into two distinct packages — hermod-tracing-api, carrying types and combinators, and hermod-tracing-core, carrying the full backend stack including EKG and Prometheus (hermod-tracing PR#16). This split will allow downstream packages that only need to instrument their own code to avoid pulling in the full backend stack as a dependency.

Infrastructure

The genesis cache overhaul for our performance workbench (the benchmarking automation framework) is completed and close to merging (cardano-node PR#6544). As reported last month, the new approach splits a genesis into two independently-cached halves — the heavy dataset (keys, UTxO entries, delegators, DReps) and the per-era protocol parameters — which are then reassembled on demand. This greatly widens the range of parameters a benchmarking profile can modify without causing a full cache miss. The PR additionally restores non-default Plutus cost models via the Alonzo genesis extraConfig field, and includes a full Protocol Version 11 overlay with the updated cost models and execution budgets that have been submitted as a governance action on mainnet.

Tracing

With the legacy tracing removal merged, the cardano-recon-framework and the trace-resources package have both been moved from cardano-node into the Hermod Tracing System project. The ReCon framework has been accommodated under hermod-tracing (cardano-node PR#6598, hermod-tracing PR#11); trace-resources — which provides cross-platform OS-level resource sampling (CPU, memory, network I/O, filesystem I/O, thread count) — has been renamed hermod-trace-resources (hermod-tracing PR#14), with its module namespace updated from Cardano.Logging.Resources.* to Hermod.Tracing.Resources.*. All logic, platform-specific C bindings, and tests are preserved unchanged.

The cardano-tracer timeseries HTTP API and its accompanying Grafana datasource, which we reported as being in testing last month, have now been merged (cardano-node PR#6562). The API provides PromQL-like queries over metrics timeseries stored by cardano-tracer, aligned closely with the Prometheus HTTP API schema so that existing Grafana integrations and community-built tooling can reuse familiar glue code. The Grafana datasource shipped alongside it replaces the now-removed RTView and includes a reference dashboard for operators to build from.

The cardano-recon-framework formula parsers now accept ASCII alternatives to their Unicode operators (hermod-tracing PR#15). Spellings such as \globally, \finally, && and => are now valid alongside the original Unicode forms, as are numeric indices in parentheses (e.g. \globallyN(2)). This makes authoring LTL properties more accessible in environments where Unicode input is inconvenient, and ships as part of v1.4.0.