ram_{free,total}: system fallback if other fails

Author: scivision

+stdlib/+sys/ram_free.m

@@ -0,0 +1,20 @@
+function bytes = ram_free()
+
+bytes = 0;
+
+if ispc()
+  cmd = 'pwsh -c "(Get-CimInstance -ClassName CIM_OperatingSystem).FreePhysicalMemory * 1KB"';
+elseif ismac()
+  cmd = 'sysctl -n hw.memsize';
+else
+  cmd = "free -b | awk '/Mem:/ {print $4}'";
+end
+
+[s, m] = system(cmd);
+if s == 0
+  bytes = str2double(m);
+end
+
+bytes = uint64(bytes);
+
+end

+stdlib/+sys/ram_total.m

@@ -0,0 +1,20 @@
+function bytes = ram_total()
+
+bytes = 0;
+
+if ispc()
+  cmd = 'pwsh -c "(Get-CimInstance -ClassName Win32_ComputerSystem).TotalPhysicalMemory"';
+elseif ismac()
+  cmd = 'sysctl -n hw.memsize';
+else
+  cmd = "free -b | awk '/Mem:/ {print $4}'";
+end
+
+[s, m] = system(cmd);
+if s == 0
+  bytes = str2double(m);
+end
+
+bytes = uint64(bytes);
+
+end

+stdlib/ram_free.m

@@ -20,12 +20,16 @@
 
 function bytes = ram_free()
 
+bytes = 0;
+
 if stdlib.has_java()
   bytes = ram_free_java();
 elseif stdlib.has_python()
   bytes = py_ram_free();
-else
-  bytes = ram_free_system();
+end
+
+if bytes <= 0
+  bytes = stdlib.sys.ram_free();
 end
 
 bytes = uint64(bytes);

+stdlib/ram_total.m

@@ -8,14 +8,17 @@
 
 function bytes = ram_total()
 
+bytes = 0;
 
 if stdlib.dotnet_api() >= 6
   % .NET is 2-3x faster than Java for this
   % https://learn.microsoft.com/en-us/dotnet/api/system.gcmemoryinfo.totalavailablememorybytes
   bytes = System.GC.GetGCMemoryInfo().TotalAvailableMemoryBytes;
 elseif stdlib.has_java()
   bytes = ram_total_java();
-else
+end
+
+if bytes <= 0
   bytes = ram_total_system();
 end
 

test/TestSys.m

@@ -80,19 +80,21 @@ function test_ram_total(tc)
 
 
 function test_ram_free(tc)
-
+% don't verify less than or equal total due to shaky system measurements
 f = stdlib.ram_free();
 tc.verifyGreaterThan(f, 0)
 tc.verifyClass(f, 'uint64')
 end
 
-function test_ram_free_vs_total(tc)
-t = stdlib.ram_total();
-tc.assumeGreaterThan(t, 0)
-f = stdlib.ram_free();
-tc.assumeGreaterThan(f, 0)
+end
 
-tc.verifyLessThanOrEqual(f, t, "Free RAM should be less than or equal to total RAM")
+
+methods (Test, TestTags="sys")
+
+function test_ram_free_sys(tc)
+f = stdlib.sys.ram_free();
+tc.verifyGreaterThan(f, 0)
+tc.verifyClass(f, 'uint64')
 end
 
 end