snapshot of https://github.com/ory/keto.git (master, 2026-09-16; blobs > 131072B omitted)

oryx/jsonnetsecure/schedstat.go

@@ -0,0 +1,53 @@
+// Copyright © 2026 Ory Corp
+// SPDX-License-Identifier: Apache-2.0
+
+package jsonnetsecure
+
+import (
+	"bytes"
+	"os"
+	"strconv"
+	"time"
+)
+
+// schedstat holds the scheduler statistics of a process as reported by the
+// Linux kernel in /proc/<pid>/schedstat: the CPU time the process actually
+// spent running, and the time it spent runnable but waiting for a CPU (due to
+// contention or cgroup CPU throttling).
+type schedstat struct {
+	cpuTime      time.Duration
+	runqueueWait time.Duration
+}
+
+// readSchedstat returns the cumulative scheduler statistics for pid. It
+// reports ok=false on platforms without /proc/<pid>/schedstat (e.g. macOS,
+// Windows) and on Linux kernels built without CONFIG_SCHED_INFO.
+func readSchedstat(pid int) (schedstat, bool) {
+	raw, err := os.ReadFile("/proc/" + strconv.Itoa(pid) + "/schedstat")
+	if err != nil {
+		return schedstat{}, false
+	}
+	return parseSchedstat(raw)
+}
+
+// parseSchedstat parses the /proc/<pid>/schedstat format: three
+// space-separated integers (run time in nanoseconds, runqueue wait time in
+// nanoseconds, number of timeslices).
+func parseSchedstat(raw []byte) (schedstat, bool) {
+	fields := bytes.Fields(raw)
+	if len(fields) < 2 {
+		return schedstat{}, false
+	}
+	cpuTime, err := strconv.ParseInt(string(fields[0]), 10, 64)
+	if err != nil || cpuTime < 0 {
+		return schedstat{}, false
+	}
+	runqueueWait, err := strconv.ParseInt(string(fields[1]), 10, 64)
+	if err != nil || runqueueWait < 0 {
+		return schedstat{}, false
+	}
+	return schedstat{
+		cpuTime:      time.Duration(cpuTime),
+		runqueueWait: time.Duration(runqueueWait),
+	}, true
+}