From 7f7a64a1d6ef791d3b111245301d73902e9e4875 Mon Sep 17 00:00:00 2001
From: Waley Chen <waleycz@gmail.com>
Date: Thu, 25 Feb 2016 18:09:15 -0500
Subject: SERVER-22398 Add SystemInfo::numAvailableCores

---
 src/mongo/util/processinfo_windows.cpp | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

(limited to 'src/mongo/util/processinfo_windows.cpp')

diff --git a/src/mongo/util/processinfo_windows.cpp b/src/mongo/util/processinfo_windows.cpp
index 224cd5a896a..e39fa6778da 100644
--- a/src/mongo/util/processinfo_windows.cpp
+++ b/src/mongo/util/processinfo_windows.cpp
@@ -31,6 +31,9 @@
 
 #include "mongo/platform/basic.h"
 
+#include <bitset>
+#include <boost/none.hpp>
+#include <boost/optional.hpp>
 #include <iostream>
 #include <psapi.h>
 
@@ -73,6 +76,18 @@ ProcessInfo::ProcessInfo(ProcessId pid) {}
 
 ProcessInfo::~ProcessInfo() {}
 
+// get the number of CPUs available to the current process
+boost::optional<unsigned long> ProcessInfo::getNumAvailableCores() {
+    DWORD_PTR process_mask, system_mask;
+
+    if (GetProcessAffinityMask(GetCurrentProcess(), &process_mask, &system_mask)) {
+        std::bitset<32> mask(process_mask);
+        if (mask.count() > 0)
+            return mask.count();
+    }
+    return boost::none;
+}
+
 bool ProcessInfo::supported() {
     return true;
 }
-- 
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