Changeset 54224 in vbox for trunk/include/VBox

Timestamp:

Feb 16, 2015 10:41:32 PM (10 years ago)

Author:

vboxsync

Message:

SUP,IPRT: Started as a build fix ended up as a cleanup (mostly untested as I'm windows). We'll keep SUP_IOCTL_TSC_READ for the purpose of dealing with the i64TSCDelta == INT64_MAX in SUPReadTsc/SUPReadTscWithDelta. Moved the excessive inline code from sup.h to SUPLibAll.cpp (new file) and SUPDrv.c (apply delta). Don't bother too much about trying to share code between SUPLibAll.cpp and SUPDrv.c/++ as the SUPReadTsc[WithDelta] scenario does not care about knowing when things goes bad, it just needs a TSC that is as good as we can get. The SUPDrv.c code on the other hand probably needs other kind of status codes, assertions and whatnot to be better off with its own version of the code. Remove the now unused assembly macro for applying the delta - the way the delta is applied will not change, period, so better just document it instead.

File:

• trunk/include/VBox/sup.h (modified) (4 diffs)

trunk/include/VBox/sup.h

@@ -240 +240 @@
     /** Current CPU Frequency. */
     volatile uint64_t   u64CpuHz;
-    /** The TSC delta with reference to the master TSC. */
+    /** The TSC delta with reference to the master TSC, subtract from RDTSC. */
     volatile int64_t    i64TSCDelta;
     /** Number of errors during updating.
@@ -439 +439 @@
     ((a_pGip)->u32Mode == SUPGIPMODE_INVARIANT_TSC && !((a_pGip)->fOsTscDeltasInSync))
 
-/** Whether the application of TSC-deltas are worth it (performance matters). */
-#define GIP_TSC_DELTAS_ROUGHLY_IN_SYNC(a_pGip)         ((a_pGip)->fTscDeltasRoughlyInSync)
 
 #if defined(RT_ARCH_AMD64) || defined(RT_ARCH_X86)
@@ -1547 +1545 @@
 #if defined(RT_ARCH_AMD64) || defined(RT_ARCH_X86)
 
-/**
- * Applies the TSC delta to the supplied raw TSC value.
- *
- * @returns VBox status code.
- * @param   pGip            Pointer to the GIP.
- * @param   puTsc           Pointer to a valid TSC value before the TSC delta has been applied.
- * @param   idApic          The APIC ID of the CPU @c puTsc corresponds to.
- * @param   fDeltaApplied   Where to store whether the TSC delta was succesfully
- *                          applied or not (optional, can be NULL).
- *
- * @remarks Maybe called with interrupts disabled in ring-0!
- *
- * @note    If you change the delta calculation made here, make sure to update
- *          the assembly version in sup.mac! Also update supdrvGipMpEvent()
- *          while re-adjusting deltas while choosing a new GIP master.
- */
-DECLINLINE(int) SUPTscDeltaApply(PSUPGLOBALINFOPAGE pGip, uint64_t *puTsc, uint16_t idApic, bool *pfDeltaApplied)
-{
-    PSUPGIPCPU pGipCpu;
-    uint16_t  iCpu;
-
-    /* Validate. */
-    Assert(puTsc);
-    Assert(pGip);
-    Assert(GIP_ARE_TSC_DELTAS_APPLICABLE(pGip));
-
-    /** @todo convert these to AssertMsg() after sufficient testing before public
-     *        release. */
-    AssertMsgReturn(idApic < RT_ELEMENTS(pGip->aiCpuFromApicId), ("idApic=%u\n", idApic), VERR_INVALID_CPU_ID);
-    iCpu = pGip->aiCpuFromApicId[idApic];
-    AssertMsgReturn(iCpu < pGip->cCpus, ("iCpu=%u cCpus=%u\n", iCpu, pGip->cCpus), VERR_INVALID_CPU_INDEX);
-    pGipCpu = &pGip->aCPUs[iCpu];
-    Assert(pGipCpu);
-
-    if (RT_LIKELY(pGipCpu->i64TSCDelta != INT64_MAX))
-    {
-        *puTsc -= pGipCpu->i64TSCDelta;
-        if (pfDeltaApplied)
-            *pfDeltaApplied = true;
-    }
-    else if (pfDeltaApplied)
-        *pfDeltaApplied = false;
-
-    return VINF_SUCCESS;
-}
-
-
-/**
- * Gets the delta-adjusted TSC.
- *
- * Must only be called when GIP mode is invariant (i.e. when TSC deltas are
- * likely to be computed and available).  In other GIP modes, like async, we
- * don't bother with computing TSC deltas and therefore it is meaningless to
- * call this function, use SUPReadTSC() instead.
- *
- * @returns VBox status code.
- * @param   puTsc           Where to store the normalized TSC value.
- * @param   pidApic         Where to store the APIC ID of the CPU where the TSC
- *                          was read (optional, can be NULL). This is updated
- *                          even if the function fails with
- *                          VERR_SUPDRV_TSC_READ_FAILED. Not guaranteed to be
- *                          updated for other failures.
- *
- * @remarks May be called with interrupts disabled in ring-0!
- */
-DECLINLINE(int) SUPGetTsc(uint64_t *puTsc, uint16_t *pidApic)
-{
-# ifdef IN_RING3
-
-    /** @todo Use rdtscp after figuring out what the host OS has stuffed into the
-     *        TSC_AUX msr, otherwise use the fallback below. */
-    int cTries = 10;
-    Assert(GIP_ARE_TSC_DELTAS_APPLICABLE(g_pSUPGlobalInfoPage));
-    do
-    {
-        uint16_t idApicBefore;
-        uint16_t idApicAfter;
-
-        /* The chance of getting preempted twice here is rather low, hence we
-           take this approach. Performance matters, see @bugref{6710} comment #24. */
-        idApicBefore = ASMGetApicId();
-        *puTsc       = ASMReadTSC();
-        idApicAfter  = ASMGetApicId();
-        if (RT_LIKELY(idApicBefore == idApicAfter))
-        {
-            SUPTscDeltaApply(g_pSUPGlobalInfoPage, puTsc, idApicBefore, NULL);
-            if (pidApic)
-                *pidApic = idApicBefore;
-            return VINF_SUCCESS;
-        }
-    } while (cTries-- > 0);
-    *puTsc = 0;
-    return VERR_SUPDRV_TSC_READ_FAILED;
-
-    /** @todo get rid of SUPR3ReadTsc(). */
-    //return SUPR3ReadTsc(puTsc, pidApic);
-# else
-    RTCCUINTREG uFlags;
-    uint16_t    idApic;
-    bool        fDeltaApplied;
-    int         rc;
-
-    /** @todo Use rdtscp after figuring out what the host OS has stuffed into the
-     *        TSC_AUX msr, otherwise use the fallback below. */
-
-    /* Validate. */
-    Assert(puTsc);
-
-    uFlags = ASMIntDisableFlags();
-    idApic = ASMGetApicId();        /* Doubles as serialization. */
-    *puTsc = ASMReadTSC();
-    ASMSetFlags(uFlags);
-
-    if (pidApic)
-        *pidApic = idApic;
-
-    rc = SUPTscDeltaApply(g_pSUPGlobalInfoPage, puTsc, idApic, &fDeltaApplied);
-    AssertRC(rc);
-    return fDeltaApplied ? VINF_SUCCESS : VERR_SUPDRV_TSC_READ_FAILED;
-# endif
-}
-
+/** @internal */
+SUPDECL(uint64_t) SUPReadTscWithDelta(void);
 
 /**
@@ -1682 +1560 @@
 {
     if (    GIP_ARE_TSC_DELTAS_APPLICABLE(g_pSUPGlobalInfoPage)
-        && !GIP_TSC_DELTAS_ROUGHLY_IN_SYNC(g_pSUPGlobalInfoPage))
-    {
-        uint64_t u64Tsc = UINT64_MAX;
-        int rc = SUPGetTsc(&u64Tsc, NULL /* pidApic */);
-        NOREF(rc);
-#ifdef DEBUG_ramshankar
-        AssertRC(rc);
-#endif
-        return u64Tsc;
-    }
+        && !g_pSUPGlobalInfoPage->fTscDeltasRoughlyInSync)
+        return SUPReadTscWithDelta();
     return ASMReadTSC();
 }