Changeset 26479 in vbox for trunk/src/VBox/VMM

Timestamp:

Feb 13, 2010 12:36:53 PM (15 years ago)

Author:

vboxsync

Message:

AsyncCompletion: Don't spawn a new I/O manager if only one endpoint produces the load. Fixes huge amount of I/O managers during I/O intensive tasks

File:

• trunk/src/VBox/VMM/PDMAsyncCompletionFileNormal.cpp (modified) (3 diffs)

trunk/src/VBox/VMM/PDMAsyncCompletionFileNormal.cpp

@@ -202 +202 @@
 }
 
+static bool pdmacFileAioMgrNormalIsBalancePossible(PPDMACEPFILEMGR pAioMgr)
+{
+    /* Balancing doesn't make sense with only one endpoint. */
+    if (pAioMgr->cEndpoints == 1)
+        return false;
+
+    /* Doesn't make sens to move endpoints if only one produces the whole load */
+    unsigned cEndpointsWithLoad = 0;
+
+    PPDMASYNCCOMPLETIONENDPOINTFILE pCurr = pAioMgr->pEndpointsHead;
+
+    while (pCurr)
+    {
+        if (pCurr->AioMgr.cReqsPerSec)
+            cEndpointsWithLoad++;
+
+        pCurr = pCurr->AioMgr.pEndpointNext;
+    }
+
+    return (cEndpointsWithLoad > 1);
+}
+
 /**
  * Creates a new I/O manager and spreads the I/O load of the endpoints
@@ -214 +236 @@
     int rc = VINF_SUCCESS;
 
-    /* Splitting can't be done with only one open endpoint. */
-    if (pAioMgr->cEndpoints > 1)
+    /*
+     * Check if balancing would improve the situation.
+     */
+    if (pdmacFileAioMgrNormalIsBalancePossible(pAioMgr))
     {
         rc = pdmacFileAioMgrCreate((PPDMASYNCCOMPLETIONEPCLASSFILE)pAioMgr->pEndpointsHead->Core.pEpClass,
@@ -274 +298 @@
         }
     }
+    else
+        Log(("AIOMgr: Load balancing would not improve anything\n"));
 }