Changeset 2565 in vbox for trunk/src/VBox

Timestamp:

May 9, 2007 4:28:03 PM (18 years ago)

Author:

vboxsync

Message:

A little experiment trying to get rid of the critsect contention in DevATA.

Location:

trunk/src/VBox

Files:

• Devices/Storage/DevATA.cpp (modified) (6 diffs)
• VMM/PDMCritSect.cpp (modified) (2 diffs)
• VMM/PDMInternal.h (modified) (1 diff)
• VMM/VMMAll/PDMAllCritSect.cpp (modified) (2 diffs)

trunk/src/VBox/Devices/Storage/DevATA.cpp

@@ -339 +339 @@
     /** The position at which to get a new request for the AIO thread. */
     uint8_t             AsyncIOReqTail;
-    uint8_t             Alignment3[2]; /** Explicit padding of the 2 byte gap. */
+    uint8_t             Alignment3[2]; /**< Explicit padding of the 2 byte gap. */
     /** Magic delay before triggering interrupts in DMA mode. */
     uint32_t            DelayIRQMillies;
@@ -597 +597 @@
     rc = RTSemMutexRelease(pCtl->AsyncIORequestMutex);
     AssertRC(rc);
-    rc = RTSemEventSignal(pCtl->AsyncIOSem);
-    AssertRC(rc);
+    LogBird(("ata: %x: signalling\n", pCtl->IOPortBase1));
+    rc = PDMR3CritSectScheduleExitEvent(&pCtl->lock, pCtl->AsyncIOSem); 
+    if (VBOX_FAILURE(rc))
+    {
+        LogBird(("ata: %x: schedule failed, rc=%Vrc\n", pCtl->IOPortBase1, rc));
+        rc = RTSemEventSignal(pCtl->AsyncIOSem);
+        AssertRC(rc);
+    }
 }
 
@@ -3990 +3996 @@
         if (pReq == NULL)
         {
+            LogBird(("ata: %x: going to sleep...\n", pCtl->IOPortBase1));
             rc = RTSemEventWait(pCtl->AsyncIOSem, RT_INDEFINITE_WAIT);
+            LogBird(("ata: %x: waking up\n", pCtl->IOPortBase1));
             if (VBOX_FAILURE(rc) || pCtl->fShutdown)
                 break;
@@ -4020 +4028 @@
         {
         STAM_PROFILE_START(&pCtl->StatLockWait, a);
+        LogBird(("ata: %x: entering critsect\n", pCtl->IOPortBase1));
         PDMCritSectEnter(&pCtl->lock, VINF_SUCCESS);
+        LogBird(("ata: %x: entered\n", pCtl->IOPortBase1));
         STAM_PROFILE_STOP(&pCtl->StatLockWait, a);
         }
@@ -4358 +4368 @@
         }
 
+        LogBird(("ata: %x: leaving critsect\n", pCtl->IOPortBase1));
         PDMCritSectLeave(&pCtl->lock);
     }
@@ -4740 +4751 @@
     else
         AssertMsgFailed(("ataIOPortWrite1: unsupported write to port %x val=%x size=%d\n", Port, u32, cb));
+    LogBird(("ata: leaving critsect\n"));
     PDMCritSectLeave(&pCtl->lock);
+    LogBird(("ata: left critsect\n"));
     return rc;
 }

trunk/src/VBox/VMM/PDMCritSect.cpp

@@ -119 +119 @@
         pCritSect->pVMGC = pVM->pVMGC;
         pCritSect->pvKey = pvKey;
+        pCritSect->EventToSignal = NIL_RTSEMEVENT;
         pCritSect->pNext = pVM->pdm.s.pCritSects;
         pVM->pdm.s.pCritSects = pCritSect;
@@ -323 +324 @@
 }
 
+
+/**
+ * Schedule a event semaphore for signalling upon critsect exit.
+ *
+ * @returns VINF_SUCCESS on success.
+ * @returns VERR_TOO_MANY_SEMAPHORES if an event was already scheduled.
+ * @returns VERR_NOT_OWNER if we're not the critsect owner.
+ * @returns VERR_SEM_DESTROYED if RTCritSectDelete was called while waiting.
+ * @param   pCritSect       The critical section.
+ * @param   EventToSignal     The semapore that should be signalled.
+ */
+PDMR3DECL(int) PDMR3CritSectScheduleExitEvent(PPDMCRITSECT pCritSect, RTSEMEVENT EventToSignal)
+{
+    Assert(EventToSignal != NIL_RTSEMEVENT);
+    if (RT_UNLIKELY(!RTCritSectIsOwner(&pCritSect->s.Core)))
+        return VERR_NOT_OWNER;
+    if (RT_LIKELY(   pCritSect->s.EventToSignal == NIL_RTSEMEVENT
+                  || pCritSect->s.EventToSignal == EventToSignal))
+    {
+        pCritSect->s.EventToSignal = EventToSignal;
+        return VINF_SUCCESS;
+    }
+    return VERR_TOO_MANY_SEMAPHORES;
+}
+

trunk/src/VBox/VMM/PDMInternal.h

@@ -146 +146 @@
     /** Pointer to the VM - GCPtr. */
     GCPTRTYPE(PVM)      pVMGC;
-#if GC_ARCH_BITS == 32
-    uint32_t            u32Padding;
-#endif
+#if HC_ARCH_BITS == 64 && GC_ARCH_BITS == 32
+    uint32_t            padding;
+#endif 
+    /** Event semaphore that is scheduled to be signaled upon leaving the 
+     * critical section. This is Ring-3 only of course. */
+    RTSEMEVENT          EventToSignal;
     /** R0/GC lock contention. */
     STAMCOUNTER         StatContentionR0GCLock;

trunk/src/VBox/VMM/VMMAll/PDMAllCritSect.cpp

@@ -34 +34 @@
 #include <iprt/asm.h>
 #include <iprt/assert.h>
+#ifdef IN_RING3
+# include <iprt/semaphore.h>
+#endif 
 
 
@@ -107 +110 @@
         STAM_PROFILE_ADV_STOP(&pCritSect->s.StatLocked, l);
 # endif
-    int rc = RTCritSectLeave(&pCritSect->s.Core);
-    AssertRC(rc);
+    RTSEMEVENT EventToSignal = pCritSect->s.EventToSignal;
+    if (RT_LIKELY(EventToSignal == NIL_RTSEMEVENT))
+    {
+        int rc = RTCritSectLeave(&pCritSect->s.Core);
+        AssertRC(rc);
+    }
+    else
+    {
+        pCritSect->s.EventToSignal = NIL_RTSEMEVENT;
+        int rc = RTCritSectLeave(&pCritSect->s.Core);
+        AssertRC(rc);
+        LogBird(("signalling %#x\n", EventToSignal));
+        rc = RTSemEventSignal(EventToSignal);
+        AssertRC(rc);
+    }
 
-#else
+#else /* !IN_RING3 */
     Assert(VALID_PTR(pCritSect));
     Assert(pCritSect->s.Core.u32Magic == RTCRITSECT_MAGIC);