Fix _SC_NPROCESSORS_ONLN on Windows

_SC_NPROCESSORS_ONLN was returning the wrong value on Windows because
GetLogicalProcessorInformation() returns data about caches, nodes and
packages in addition to processors.

Modified by Jens to use hweight32()

Signed-off-by: Jens Axboe <[email protected]>

os/windows/posix.c

@@ -20,6 +20,7 @@
 #include <sys/poll.h>
 
 #include "../os-windows.h"
+#include "../../lib/hweight.h"
 
 extern unsigned long mtime_since_now(struct timeval *);
 extern void fio_gettime(struct timeval *, void *);
@@ -42,20 +43,52 @@ int vsprintf_s(
   const char *format,
   va_list argptr);
 
+int GetNumLogicalProcessors(void)
+{
+	SYSTEM_LOGICAL_PROCESSOR_INFORMATION *processor_info = NULL;
+	DWORD len = 0;
+	DWORD num_processors = 0;
+	DWORD error = 0;
+	DWORD i;
+
+	while (!GetLogicalProcessorInformation(processor_info, &len)) {
+		error = GetLastError();
+		if (error == ERROR_INSUFFICIENT_BUFFER)
+			processor_info = malloc(len);
+		else {
+			log_err("Error: GetLogicalProcessorInformation failed: %d\n", error);
+			return -1;
+		}
+
+		if (processor_info == NULL) {
+			log_err("Error: failed to allocate memory for GetLogicalProcessorInformation");
+			return -1;
+		}
+	}
+
+	for (i = 0; i < len / sizeof(SYSTEM_LOGICAL_PROCESSOR_INFORMATION); i++)
+	{
+		if (processor_info[i].Relationship == RelationProcessorCore)
+			num_processors += hweight32(processor_info[i].ProcessorMask);
+	}
+
+	free(processor_info);
+	return num_processors;
+}
+
 long sysconf(int name)
 {
-	long long val = -1;
-	DWORD len;
-	SYSTEM_LOGICAL_PROCESSOR_INFORMATION processorInfo;
+	long val = -1;
 	SYSTEM_INFO sysInfo;
 	MEMORYSTATUSEX status;
 
 	switch (name)
 	{
 	case _SC_NPROCESSORS_ONLN:
-		len = sizeof(SYSTEM_LOGICAL_PROCESSOR_INFORMATION);
-		GetLogicalProcessorInformation(&processorInfo, &len);
-		val = len / sizeof(SYSTEM_LOGICAL_PROCESSOR_INFORMATION);
+		val = GetNumLogicalProcessors();
+		if (val == -1)
+			log_err("_SC_NPROCESSORS_ONLN failed\n");
+
 		break;
 
 	case _SC_PAGESIZE: