sys.device: 100x speedup on Windows

Author: scivision

+stdlib/+sys/device.m

@@ -9,15 +9,17 @@
 
 function [i, cmd] = device(p)
 
-i = uint64([]);
-if ~stdlib.exists(p), return, end
+i = [];
 
 if ispc()
-  c0 = 'pwsh -c "(Get-CimInstance -ClassName Win32_Volume -Filter \"DriveLetter = ''';
-  c1 = stdlib.root_name(stdlib.absolute(p));
-  c2 = '''\").SerialNumber"';
-  % needs to be strcat as it could be char, or cast implicitly to string
-  cmd = strcat(c0, c1, c2);
+  rn = stdlib.root_name(stdlib.absolute(p));
+
+  % Get-CimInstance works, but is 100x slower
+  % c0 = 'pwsh -c "(Get-CimInstance -ClassName Win32_Volume -Filter \"DriveLetter = ''';
+  % c2 = '''\").SerialNumber"';
+  % cmd = strcat(c0, rn, c2);
+
+  cmd = sprintf('vol "%s"', rn);
 elseif ismac()
   cmd = sprintf('stat -f %%d "%s"', p);
 else
@@ -27,7 +29,13 @@
 if stdlib.exists(p)
   [s, m] = system(cmd);
   if s == 0
-    i = str2double(m);
+    if ispc()
+      r = extractAfter(m, 'Volume Serial Number is ');
+      r = [r(1:4) r(6:9)];
+      i = hex2dec(r);
+    else
+      i = str2double(m);
+    end
   end
 end
 

+stdlib/device.m

@@ -8,8 +8,8 @@
 
 function [i, b] = device(file, backend)
 arguments
-  file
-  backend (1,:) string = ["java", "perl", "python", "sys"]
+  file string
+  backend (1,:) string = ["java", "python", "perl", "sys"]
 end
 
 o = stdlib.Backend(mfilename(), backend);

example/BenchmarkDevice.m

@@ -0,0 +1,45 @@
+classdef (SharedTestFixtures={ matlab.unittest.fixtures.PathFixture("..")}) ...
+    BenchmarkDevice < matlab.perftest.TestCase
+
+properties
+exist = "."
+not_exist = tempname()
+fun = @stdlib.device
+end
+
+properties(TestParameter)
+backend
+end
+
+methods (TestParameterDefinition, Static)
+function backend = setupBackend()
+  backend = init_backend('device');
+end
+end
+
+
+methods (Test)
+
+function bench_exist(tc, backend)
+tc.startMeasuring()
+i = tc.fun(tc.exist, backend);
+tc.stopMeasuring()
+
+tc.verifyClass(i, 'uint64')
+tc.assertNotEmpty(i)
+tc.verifyGreaterThan(i, 0)
+end
+
+
+function bench_not_exist(tc, backend)
+tc.startMeasuring()
+i = tc.fun(tc.not_exist, backend);
+tc.stopMeasuring()
+
+tc.verifyClass(i, 'uint64')
+tc.verifyEmpty(i)
+end
+
+end
+
+end

example/BenchmarkDeviceRun.m

@@ -0,0 +1,20 @@
+function [r, s] =  BenchmarkDeviceRun()
+tname = "BenchmarkDevice";
+
+%% Exist
+r.same = run_bench(tname + "/bench_exist");
+s.exist = sampleSummary(r.same);
+disp(sortrows(s.exist, "Median"))
+%% Not Exist
+r.not = run_bench(tname + "/bench_not_exist");
+s.not = sampleSummary(r.not);
+disp(sortrows(s.not, "Median"))
+
+end
+
+
+function result = run_bench(name)
+suite = testsuite(name);
+exp = matlab.perftest.TimeExperiment.limitingSamplingError(MaxSamples=20, RelativeMarginOfError=0.1);
+result = exp.run(suite);
+end

example/BenchmarkInode.m

@@ -1,6 +1,12 @@
 classdef (SharedTestFixtures={ matlab.unittest.fixtures.PathFixture("..")}) ...
     BenchmarkInode < matlab.perftest.TestCase
 
+properties
+exist = mfilename('fullpath') + ".m"
+not_exist = tempname()
+fun = @stdlib.inode
+end
+
 properties(TestParameter)
 backend
 end
@@ -15,9 +21,8 @@
 methods (Test)
 
 function bench_exist(tc, backend)
-file = mfilename('fullpath') + ".m";
 tc.startMeasuring()
-i = stdlib.inode(file, backend);
+i = tc.fun(tc.exist, backend);
 tc.stopMeasuring()
 
 tc.verifyClass(i, 'uint64')
@@ -27,9 +32,8 @@ function bench_exist(tc, backend)
 
 
 function bench_not_exist(tc, backend)
-file = tempname();
 tc.startMeasuring()
-i = stdlib.inode(file, backend);
+i = tc.fun(tc.not_exist, backend);
 tc.stopMeasuring()
 
 tc.verifyClass(i, 'uint64')

example/BenchmarkInodeRun.m

@@ -1,10 +1,12 @@
 function [r, s] =  BenchmarkInodeRun()
+tname = "BenchmarkInode";
+
 %% Exist
-r.same = run_bench('BenchmarkInode/bench_exist');
+r.same = run_bench(tname + "/bench_exist");
 s.exist = sampleSummary(r.same);
 disp(sortrows(s.exist, "Median"))
 %% Not Exist
-r.not = run_bench('BenchmarkInode/bench_not_exist');
+r.not = run_bench(tname + "/bench_not_exist");
 s.not = sampleSummary(r.not);
 disp(sortrows(s.not, "Median"))
 
@@ -13,6 +15,6 @@
 
 function result = run_bench(name)
 suite = testsuite(name);
-exp = matlab.perftest.TimeExperiment.limitingSamplingError(MaxSamples=25, RelativeMarginOfError=0.1);
+exp = matlab.perftest.TimeExperiment.limitingSamplingError(MaxSamples=20, RelativeMarginOfError=0.1);
 result = exp.run(suite);
 end