cpu_load: add python and sys methods

Author: scivision

+stdlib/+java/cpu_load.m

@@ -0,0 +1,16 @@
+function L = cpu_load()
+
+
+b = javaMethod("getOperatingSystemMXBean", "java.lang.management.ManagementFactory");
+
+L = b.getSystemLoadAverage();
+if L < 0
+  if stdlib.java_api() < 14
+    L = b.getSystemCpuLoad();
+  else
+    % https://docs.oracle.com/en/java/javase/21/docs/api/jdk.management/com/sun/management/OperatingSystemMXBean.html#getCpuLoad()
+    L = b.getCpuLoad();
+  end
+end
+
+end

+stdlib/+python/cpu_load.m

@@ -0,0 +1,6 @@
+function L = cpu_load()
+
+Lavg = py.os.getloadavg();
+L = double(Lavg(1));
+
+end

+stdlib/+sys/cpu_load.m

@@ -0,0 +1,25 @@
+function L = cpu_load()
+
+L = NaN;
+
+if ispc()
+  cmd = 'pwsh -c "Get-CimInstance -ClassName Win32_Processor | Measure-Object -Property LoadPercentage -Average | Select-Object -ExpandProperty Average"';
+elseif ismac()
+  cmd = "sysctl -n vm.loadavg | awk '{print $2}'";
+else
+  cmd = "cat /proc/loadavg | awk '{print $1}'";
+end
+
+[status, m] = system(cmd);
+if status ~= 0
+  warning("stdlib:cpu_load:OSError", "Failed to get CPU load");
+  return
+end
+
+L = str2double(strtrim(m));
+
+if ispc()
+  L = L / 100.;
+end
+
+end

+stdlib/cpu_load.m

@@ -1,26 +1,18 @@
 %% CPU_LOAD get total physical CPU load
-% requires: java
 %
 % Returns the "recent cpu usage" for the whole system.
 %
-% This value is a double in the [0.0,1.0] interval.
-% A value of 0.0 means that all CPUs were idle during the recent period of time observed, while a value of 1.0 means that all CPUs were actively running 100% of the time during the recent period being observed.
-% All values betweens 0.0 and 1.0 are possible depending of the activities going on in the system.
-% If the system recent cpu usage is not available, the method returns a negative value.
+% This value is a double greater than 0.
+% If the system recent cpu usage is not available, the method returns a negative or NaN value.
 
-function L = cpu_load()
+function L = cpu_load(method)
+arguments
+  method (1,:) string = ["java", "python", "sys"]
+end
 
-b = javaMethod("getOperatingSystemMXBean", "java.lang.management.ManagementFactory");
+fun = choose_method(method, "cpu_load");
 
-if stdlib.java_api() < 14
-  % https://docs.oracle.com/en/java/javase/21/docs/api/jdk.management/com/sun/management/OperatingSystemMXBean.html#getSystemCpuLoad()
-  L = b.getSystemCpuLoad();
-else
-  % https://docs.oracle.com/en/java/javase/21/docs/api/jdk.management/com/sun/management/OperatingSystemMXBean.html#getCpuLoad()
-  L = b.getCpuLoad();
-end
+L = fun();
 
-end
 
-%!assert(cpu_load()>=0)
-%!assert(cpu_load()<=1)
+end

+stdlib/private/choose_method.m

@@ -24,11 +24,17 @@
         if ~isunix(), continue, end
       end
     case "python"
+
       has = @stdlib.has_python;
 
       if endsWith(name, ["filesystem_type", "ram_total", "ram_free"])
         if ~stdlib.python.has_psutil(); continue, end
       end
+
+      if endsWith(name, "cpu_load")
+        if ~isunix(), continue, end
+      end
+
     case {"legacy", "sys"}, has = true;
     case "native", has = stdlib.strempty(minVersion) || ~isMATLABReleaseOlderThan(minVersion);
     otherwise

test/TestJava.m

@@ -27,11 +27,6 @@ function test_java_api(tc)
 end
 
 
-function test_cpu_load(tc)
-tc.verifyGreaterThanOrEqual(stdlib.cpu_load(), 0)
-end
-
-
 function test_is_regular_file(tc)
 tc.verifyFalse(stdlib.is_regular_file(stdlib.null_file()), "null file is not a regular file")
 end

test/TestSys.m

@@ -13,6 +13,7 @@
 is_admin_fun = {@stdlib.is_admin, @stdlib.sys.is_admin, @stdlib.dotnet.is_admin, @stdlib.java.is_admin, @stdlib.python.is_admin}
 ram_free_method = {'sys', 'java', 'python'}
 ram_total_method = {'sys', 'dotnet', 'java', 'python'}
+cpu_load_method = {"java", "python", "sys"}
 end
 
 methods(TestClassSetup)
@@ -52,6 +53,19 @@ function test_get_pid(tc)
 end
 
 
+function test_cpu_load(tc, cpu_load_method)
+n = "stdlib." + cpu_load_method + ".cpu_load";
+h = @stdlib.cpu_load;
+tc.assertNotEmpty(which(n))
+try
+  r = h(cpu_load_method);
+  tc.verifyGreaterThan(r, 0.)
+catch e
+  tc.verifyEqual(e.identifier, 'stdlib:choose_method:NameError')
+end
+end
+
+
 function test_get_shell(tc)
 tc.assumeFalse(tc.CI, "get_shell is not tested in CI due to platform differences")
 tc.verifyNotEmpty(stdlib.get_shell())