Changeset 57059 in vbox for trunk/include/VBox

Timestamp:

Jul 23, 2015 1:18:14 PM (10 years ago)

Author:

vboxsync

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

101780

Message:

SUP: Threshold adjustment in SUPIsTscFreqCompatibleEx.

File:

• trunk/include/VBox/sup.h (modified) (3 diffs)

trunk/include/VBox/sup.h

@@ -555 +555 @@
  * Worker for SUPIsTscFreqCompatible().
  *
- * @param uBaseCpuHz        The reference CPU frequency of the system.
- * @param uCpuHz            The CPU frequency to compare with the base.
+ * @param   uBaseCpuHz      The reference CPU frequency of the system.
+ * @param   uCpuHz          The CPU frequency to compare with the base.
+ * @param   fRelax          Whether to use a more relaxed threshold (like
+ *                          for when running in a virtualized environment).
  *
  * @returns true if it's compatible, false otherwise.
  * @remarks Don't use directly, use SUPIsTscFreqCompatible() instead. This is
- *          to be used by tstGIP-2 (or the like).
- */
-DECLINLINE(bool) SUPIsTscFreqCompatibleEx(uint64_t uBaseCpuHz, uint64_t uCpuHz)
+ *          to be used by tstGIP-2 or the like.
+ */
+DECLINLINE(bool) SUPIsTscFreqCompatibleEx(uint64_t uBaseCpuHz, uint64_t uCpuHz, bool fRelax)
 {
     if (uBaseCpuHz != uCpuHz)
@@ -568 +570 @@
         /* Arbitrary tolerance threshold, tweak later if required, perhaps
            more tolerance on lower frequencies and less tolerance on higher. */
-        uint64_t uLo = (uBaseCpuHz << 11) / 2049;
-        uint64_t uHi = uBaseCpuHz + (uBaseCpuHz - uLo);
+        uint16_t uThr = !fRelax ? 666 /* 0.15% */ : 125 /* 0.8% */;
+        uint64_t uLo  = uBaseCpuHz / uThr;
+        uint64_t uHi  = uBaseCpuHz + (uBaseCpuHz - uLo);
         if (   uCpuHz < uLo
             || uCpuHz > uHi)
@@ -583 +586 @@
  *
  * @param   u64CpuHz        The TSC frequency to check.
+ * @param   fRelax          Whether to use a more relaxed threshold (like
+ *                          for when running in a virtualized environment).
  *
  * @returns true if it's compatible, false otherwise.
  */
-DECLINLINE(bool) SUPIsTscFreqCompatible(uint64_t u64CpuHz)
+DECLINLINE(bool) SUPIsTscFreqCompatible(uint64_t u64CpuHz, bool fRelax)
 {
     PSUPGLOBALINFOPAGE pGip = g_pSUPGlobalInfoPage;
     if (   pGip
         && pGip->u32Mode == SUPGIPMODE_INVARIANT_TSC)
-        return SUPIsTscFreqCompatibleEx(pGip->u64CpuHz, u64CpuHz);
+        return SUPIsTscFreqCompatibleEx(pGip->u64CpuHz, u64CpuHz, fRelax);
     return false;
 }