fix: cuda metrics and initialize estimated rate gauge

crates/engine-gpu-cuda/src/lib.rs

@@ -485,6 +485,11 @@ impl CudaEngine {
                             metrics::inc_candidates_false_positive("gpu-cuda");
                         }
                         hash_count = hash_count.saturating_add(covered);
+                        #[cfg(feature = "metrics")]
+                        {
+                            metrics::inc_candidates_false_positive("gpu-cuda");
+                        }
+                        hash_count = hash_count.saturating_add(covered);
                         if covered < total_elems_u64 {
                             return Ok(EngineStatus::Exhausted { hash_count });
                         }

crates/miner-service/Cargo.toml

@@ -10,7 +10,7 @@ default = ["cpu", "metrics", "montgomery"]
 # Enable CPU engine by default.
 cpu = ["engine-cpu"]
 # Optional metrics/observability (Prometheus endpoint).
-metrics = ["dep:metrics", "engine-montgomery?/metrics", "metrics/http-exporter"]
+metrics = ["dep:metrics", "engine-montgomery?/metrics", "engine-gpu-cuda?/metrics", "metrics/http-exporter"]
 # Optional GPU backends (off by default).
 cuda = ["dep:engine-gpu-cuda", "engine-gpu-cuda/cuda"]
 opencl = ["engine-gpu-opencl"]

crates/miner-service/src/lib.rs

@@ -130,6 +130,8 @@ impl MiningService {
             metrics::set_job_status_gauge(self.engine.name(), &job_id, "completed", 0);
             metrics::set_job_status_gauge(self.engine.name(), &job_id, "failed", 0);
             metrics::set_job_status_gauge(self.engine.name(), &job_id, "cancelled", 0);
+            // initialize estimated rate gauge so it appears immediately
+            metrics::set_job_estimated_rate(self.engine.name(), &job_id, 0.0);
             // increment active jobs
             {
                 let mut g = self.active_jobs_gauge.lock().await;