Changeset 2981 in kBuild

Timestamp:

Oct 12, 2016 11:12:58 AM (8 years ago)

Author:

bird

Message:

kmk: Use GetActiveProcessorCount instead of GetSystemInfo when possible. Good for systems with lots of CPUs. However, limit it to 64 so we don't run into trouble with child waiting in subproc.

File:

• trunk/src/kmk/main.c (modified) (1 diff)

trunk/src/kmk/main.c

@@ -1239 +1239 @@
 # ifdef WINDOWS32
     /* Windows: Count the active CPUs. */
-    int cpus, i;
-    SYSTEM_INFO si;
-    GetSystemInfo(&si);
-    for (i = cpus = 0; i < sizeof(si.dwActiveProcessorMask) * 8; i++)
+    int cpus;
+
+    /* Process groups (W7+). */
+    typedef DWORD (WINAPI *PFNGETACTIVEPROCESSORCOUNT)(DWORD);
+    PFNGETACTIVEPROCESSORCOUNT pfnGetActiveProcessorCount;
+    pfnGetActiveProcessorCount = (PFNGETACTIVEPROCESSORCOUNT)GetProcAddress(GetModuleHandleW(L"kernel32.dll"),
+                                                                            "GetActiveProcessorCount");
+    if (pfnGetActiveProcessorCount)
+      cpus = pfnGetActiveProcessorCount(ALL_PROCESSOR_GROUPS);
+    /* Legacy (<= Vista). */
+    else
       {
-        if (si.dwActiveProcessorMask & 1)
-          cpus++;
-        si.dwActiveProcessorMask >>= 1;
+        int i;
+        SYSTEM_INFO si;
+        GetSystemInfo(&si);
+        for (i = cpus = 0; i < sizeof(si.dwActiveProcessorMask) * 8; i++)
+          {
+            if (si.dwActiveProcessorMask & 1)
+              cpus++;
+            si.dwActiveProcessorMask >>= 1;
+          }
       }
-    return cpus ? cpus : 1;
+    if (!cpus)
+      cpus = 1;
+    if (cpus > 64)
+      cpus = 64; /* (wait for multiple objects limit) */
+    return cpus;
 
 # elif defined(__OS2__)