Changeset 72637 in vbox for trunk/src/VBox/Devices

Timestamp:

Jun 21, 2018 11:34:44 AM (7 years ago)

Author:

vboxsync

svn:sync-xref-src-repo-rev:

123141

Message:

DevATA: Yield early in the status polling from raw-mode & ring-0. Looks like previous changes caused a w2k install regression for raw-mode. bugref:1960

File:

• trunk/src/VBox/Devices/Storage/DevATA.cpp (modified) (3 diffs)

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

@@ -298 +298 @@
      * Lower is more agressive. */
     uint8_t                             cBusyStatusHackR3Rate;
-    /** Defines the RZ yield rate by number of status requests before returning
-     * to ring-3 and yielding there.  Lower is more agressive. */
+    /** Defines the R0/RC yield rate by a mask (power of 2 minus one).
+     * Lower is more agressive. */
     uint8_t                             cBusyStatusHackRZRate;
 
@@ -4528 +4528 @@
                  * especially on SMP systems where we don't gain much by
                  * yielding the CPU to someone else. */
-                if (++s->cBusyStatusHackRZ >= s->cBusyStatusHackRZRate)
+                if ((s->cBusyStatusHackRZ++ & s->cBusyStatusHackRZRate) == 1)
                 {
-                    s->cBusyStatusHackRZ = 0;
                     s->cBusyStatusHackR3 = 0; /* Forces a yield. */
                     return VINF_IOM_R3_IOPORT_READ;
@@ -6534 +6533 @@
     {
         pIf->cBusyStatusHackR3Rate = 1;
-        pIf->cBusyStatusHackRZRate = 8;
+        pIf->cBusyStatusHackRZRate = 7;
     }
     else if (cCpus <= 2)
     {
         pIf->cBusyStatusHackR3Rate = 3;
-        pIf->cBusyStatusHackRZRate = 20;
+        pIf->cBusyStatusHackRZRate = 15;
     }
     else if (cCpus <= 4)
     {
         pIf->cBusyStatusHackR3Rate = 15;
-        pIf->cBusyStatusHackRZRate = 32;
+        pIf->cBusyStatusHackRZRate = 31;
     }
     else
     {
         pIf->cBusyStatusHackR3Rate = 127;
-        pIf->cBusyStatusHackRZRate = 128;
+        pIf->cBusyStatusHackRZRate = 127;
     }