Add ServerCPULoadInfo() and ServerMemUsageInfo() admin API (#7038)

pkg/cpu/counter_linux.go

@@ -0,0 +1,40 @@
+/*
+ * Minio Cloud Storage, (C) 2019 Minio, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package cpu
+
+import (
+	"syscall"
+	"time"
+	"unsafe"
+)
+
+const (
+	// ProcessClock corresponds to the High-resolution per-process
+	// timer from the CPU represented in stdlib as CLOCK_PROCESS_CPUTIME_ID
+	processClock = 2
+)
+
+func newCounter() (counter, error) {
+	return counter{}, nil
+}
+
+func (c counter) now() time.Time {
+	var ts syscall.Timespec
+	syscall.Syscall(syscall.SYS_CLOCK_GETTIME, processClock, uintptr(unsafe.Pointer(&ts)), 0)
+	sec, nsec := ts.Unix()
+	return time.Unix(sec, nsec)
+}