Changeset 27341 in vbox for trunk/src

Timestamp:

Mar 12, 2010 7:17:05 PM (15 years ago)

Author:

vboxsync

Message:

APIC: hack to reduce OSX guests idle state CPU consumption

File:

• trunk/src/VBox/Devices/PC/DevAPIC.cpp (modified) (2 diffs)

trunk/src/VBox/Devices/PC/DevAPIC.cpp

@@ -2163 +2163 @@
 }
 
+/**
+ * This function is a hack, intended to minimize impact of not fully implemented power management support
+ * on OSX guests. We do nothing smarter than make access to certain register (ISR status for LVT[6])
+ * rather long operation from the guest's perspective. 
+ * To be removed once real reasons why power saving states not reached by OSX will be figured out.
+ * Hack seems to be safe, as guests rarely access this particular register.
+ */
+int checkHeavyRegistersPolling(APICDeviceInfo * pThis, RTGCPHYS GCPhysAddr)
+{
+    int index = (GCPhysAddr >> 4) & 0xff;
+
+    /* We pick up rarely accessed IRR status register for this check */
+    if (index != 0x26)
+        return VINF_SUCCESS;
+
+#ifdef IN_RING3
+    RTThreadSleep(10);
+    return VINF_SUCCESS;
+#else
+    return VINF_IOM_HC_MMIO_READ;
+#endif
+}
+
 #ifdef VBOX
 static
@@ -2428 +2451 @@
 #endif
 #endif /* experimental */
+            int rc = checkHeavyRegistersPolling(dev, GCPhysAddr);
+            if (rc != VINF_SUCCESS)
+                return rc;
             APIC_LOCK(dev, VINF_IOM_HC_MMIO_READ);
             *(uint32_t *)pv = apic_mem_readl(dev, s, GCPhysAddr);