fix(obs): isolate process sampler windows (#4492)

* fix(obs): isolate process sampler windows

Refs rustfs/backlog#1004
Refs rustfs/backlog#986

- add a reusable ProcessSampler so callers can own independent sysinfo refresh windows
- wire separate sampler instances for obs metrics scheduling and memory observability
- keep compatibility helpers while avoiding cross-task CPU and disk delta interference

Co-Authored-By: heihutu <heihutu@gmail.com>

* fix(obs): import process sampler bundle helper

Refs rustfs/backlog#1004
Refs rustfs/backlog#986

- import collect_process_metric_bundle_with in the metrics scheduler
- drop the stale collect_process_metric_bundle import after switching scheduler sampling to independent process samplers

Co-Authored-By: heihutu <heihutu@gmail.com>

* fix(obs): move process sampler into blocking task

Refs rustfs/backlog#1004
Refs rustfs/backlog#986

- move the memory observability process sampler into the spawn_blocking closure
- satisfy the closure static lifetime required by tokio while keeping the isolated sampler design intact

Co-Authored-By: heihutu <heihutu@gmail.com>

---------

Co-authored-by: heihutu <heihutu@gmail.com>

crates/obs/src/metrics/scheduler.rs

@@ -93,11 +93,12 @@ use crate::metrics::stats_collector::{
     collect_bucket_stats, collect_cluster_and_health_stats, collect_cluster_config_stats, collect_cluster_usage_metric_stats,
     collect_compression_cluster_stats, collect_disk_and_system_drive_stats, collect_erasure_set_stats,
     collect_host_network_stats, collect_iam_stats, collect_ilm_metric_stats, collect_internode_network_stats,
-    collect_process_metric_bundle, collect_replication_stats, collect_scanner_metric_stats,
+    collect_process_metric_bundle_with, collect_replication_stats, collect_scanner_metric_stats,
     collect_system_cpu_and_memory_stats_with,
 };
 use futures_util::FutureExt;
 use rustfs_audit::audit_target_metrics;
+use rustfs_io_metrics::ProcessSampler;
 use rustfs_notify::{notification_metrics_snapshot, notification_target_metrics};
 use rustfs_utils::get_env_opt_u64;
 use serde::Serialize;
@@ -1274,6 +1275,7 @@ pub fn init_metrics_runtime(token: CancellationToken) {
         let labels = current_process_metric_labels();
         let mut host_system = System::new_all();
         let mut host_networks = Networks::new();
+        let mut process_sampler = ProcessSampler::new();
         let process_interval = config.process_interval;
         let mut interval = metrics_interval(process_interval, Duration::ZERO);
         let now = Instant::now();
@@ -1311,7 +1313,7 @@ pub fn init_metrics_runtime(token: CancellationToken) {
                 _ = interval.tick() => {
                     run_metrics_collector_tick(health, MetricsCollectorTaskId::ProcessMetrics, "process_metrics", async {
                         let now = Instant::now();
-                        let bundle = collect_process_metric_bundle();
+                    let bundle = collect_process_metric_bundle_with(&mut process_sampler);
 
                         if now >= next_resource_run {
                             let mut metrics = collect_resource_metrics(&bundle.resource);

crates/obs/src/metrics/stats_collector.rs

@@ -37,7 +37,10 @@ use chrono::Utc;
 use rustfs_common::heal_channel::HealScanMode;
 use rustfs_common::metrics::{ScannerMetricsReport, global_metrics};
 use rustfs_io_metrics::internode_metrics::global_internode_metrics;
-use rustfs_io_metrics::{ProcessStatusSnapshot, snapshot_process_resource_and_system};
+use rustfs_io_metrics::{
+    ProcessResourceSnapshot, ProcessSampler, ProcessStatusSnapshot, ProcessSystemSnapshot, snapshot_process_resource_and_system,
+    snapshot_process_resource_and_system_with,
+};
 use std::{collections::HashMap, sync::Arc, time::SystemTime};
 use sysinfo::{Networks, System};
 use tracing::{instrument, warn};
@@ -662,6 +665,19 @@ pub async fn collect_system_drive_stats() -> (Vec<DriveDetailedStats>, DriveCoun
 #[inline]
 pub fn collect_process_metric_bundle() -> ProcessMetricBundle {
     let (resource_snapshot, process_snapshot) = snapshot_process_resource_and_system();
+    process_metric_bundle_from_snapshots(resource_snapshot, process_snapshot)
+}
+
+#[inline]
+pub fn collect_process_metric_bundle_with(sampler: &mut ProcessSampler) -> ProcessMetricBundle {
+    let (resource_snapshot, process_snapshot) = snapshot_process_resource_and_system_with(sampler);
+    process_metric_bundle_from_snapshots(resource_snapshot, process_snapshot)
+}
+
+fn process_metric_bundle_from_snapshots(
+    resource_snapshot: ProcessResourceSnapshot,
+    process_snapshot: ProcessSystemSnapshot,
+) -> ProcessMetricBundle {
     let status = match process_snapshot.status {
         ProcessStatusSnapshot::Running => ProcessStatusType::Running,
         ProcessStatusSnapshot::Sleeping => ProcessStatusType::Sleeping,