internal PMClock(PMTimer timer)
{
this.pmTimer = timer;
this.kernelTicksTotal = 0;
this.pmResidual = 0;
this.pmLastUpdate = pmTimer.Value;
}
internal static void ApicTimer(PMTimer pmTimer, ApicTimer apicTimer)
{
apicTimer.SetDivisor(1);
apicTimer.SetOneShot();
apicTimer.SetInterruptEnabled(false);
apicTimer.SetInitialCount(~0u);
uint apicLast = apicTimer.Value;
uint pmLast = pmTimer.Value;
uint pmLimit = PMTimer.FrequencyHz / 15;
uint pmAccum = 0;
uint apicNow = 0;
// Initial measurements
apicLast = apicTimer.Value;
pmLast = pmTimer.Value;
do
{
apicNow = apicTimer.Value;
uint pmNow = pmTimer.Value | 0xff000000;
pmAccum += PmDelta(pmNow, pmLast);
pmLast = pmNow;
} while (pmAccum < pmLimit);
ulong apicHz = PMTimer.FrequencyHz * (ulong)(apicLast - apicNow) / pmAccum;
DebugStub.Print("Cpu{0}: APIC timer frequency {1} Hz\n",
__arglist(Processor.CurrentProcessor.Id, apicHz));
apicTimer.SetBusFrequency((uint)apicHz);
}
internal static void CpuCycleCounter(PMTimer pmTimer)
{
uint pmLast = pmTimer.Value;
ulong tscLast = Processor.CycleCount;
uint pmLimit = PMTimer.FrequencyHz / 15;
uint pmAccum = 0;
ulong tscNow = 0;
// Initial measurements
tscLast = Processor.CycleCount;
pmLast = pmTimer.Value;
// Measurement loop
do
{
tscNow = Processor.CycleCount;
uint pmNow = pmTimer.Value;
pmAccum += PmDelta(pmNow, pmLast);
pmLast = pmNow;
} while (pmAccum < pmLimit);
ulong tscHz = PMTimer.FrequencyHz * (tscNow - tscLast) / pmAccum;
DebugStub.Print("Cpu{0}: TSC frequency {1} Hz\n",
__arglist(Processor.CurrentProcessor.Id, tscHz));
Processor.CyclesPerSecond = tscHz;
}
private void InitializeBsp(Processor rootProcessor)
{
DebugStub.Print("HalDevicesApic.Initialize()\n");
pmTimer = AcpiTables.GetPMTimer();
// Get PIC resources. Pic is masked by default.
PnpConfig picConfig
= (PnpConfig)IoSystem.YieldResources("/pnp/PNP0000", typeof(PicStub));
pic = new PicStub(picConfig);
pic.Initialize(PicBaseVector);
// Parse MP Table and create IO apics
MpResources.ParseMpTables();
ioApics = IoApic.CreateIOApics();
halPic = new Apic(ioApics);
halPic.Initialize(ApicBaseVector);
// Apic timer is used to provide one-shot timer interrupts.
halTimer = new ApicTimer(halPic);
halTimer.Initialize();
// Calibrate timers
Calibrate.CpuCycleCounter(pmTimer);
Calibrate.ApicTimer(pmTimer, halTimer);
// Legacy timer is used to time stalls when starting CPUs.
PnpConfig i8254Config
= (PnpConfig)IoSystem.YieldResources("/pnp/PNP0100", typeof(Timer8254Apic));
stallTimer = new Timer8254Apic(i8254Config);
// Real-time clock
PnpConfig rtClockConfig
= (PnpConfig)IoSystem.YieldResources("/pnp/PNP0B00", typeof(RTClockApic));
rtClock = new RTClockApic(rtClockConfig, halPic);
// Compose our HalClock from the component clocks we have available
halClock = new HalClockApic(halPic, rtClock, new PMClock(pmTimer));
SystemClock.Initialize(halClock, TimeSpan.FromHours(8).Ticks);
rootProcessor.AddPic(halPic);
rootProcessor.AddTimer(halTimer.Interrupt, halTimer);
rootProcessor.AddClock(halClock.Interrupt, halClock);
InitializeProcessorCount();
DebugReportProcessors();
halTimer.Start();
// Get the screen resources. Since we have metadata above to
// declare all fixed resources used by the screen,
// YieldResources("") will keep the resource tracking correct:
halScreen = new HalScreenDirect(IoSystem.YieldResources("", typeof(HalScreen)));
Console.Screen = (HalScreen)halScreen;
halPic.DumpState();
foreach (IoApic ioApic in ioApics)
{
ioApic.DumpRedirectionEntries();
}
pic.DumpRegisters();
}
public override void Initialize(Processor rootProcessor)
{
DebugStub.Print("HalDevices.Initialize() - Legacy\n");
pmTimer = AcpiTables.GetPMTimer();
// PIC
PnpConfig picConfig
= (PnpConfig)IoSystem.YieldResources("/pnp/PNP0000", typeof(Pic));
pic = new Pic(picConfig);
pic.Initialize();
// Timer
PnpConfig timerConfig
= (PnpConfig)IoSystem.YieldResources("/pnp/PNP0100", typeof(Timer8254LegacyPC));
timer = new Timer8254LegacyPC(timerConfig, pic);
byte timerInterrupt = timer.Initialize();
// Real-time clock
PnpConfig clockConfig
= (PnpConfig)IoSystem.YieldResources("/pnp/PNP0B00", typeof(RTClockLegacyPC));
clock = new RTClockLegacyPC(clockConfig, pic, timer);
byte clockInterrupt = clock.Initialize();
bool noisyTimer = false;
if (pmTimer != null)
{
noisyTimer = CalibrateTimers.Run(pmTimer, timer);
}
else
{
CalibrateTimers.Run(clock, timer);
}
clock.SetNoisyTimer(noisyTimer);
clock.Start();
SystemClock.Initialize(clock, TimeSpan.FromHours(8).Ticks);
rootProcessor.AddPic(pic);
rootProcessor.AddTimer(timerInterrupt, timer);
rootProcessor.AddClock(clockInterrupt, clock);
// ----------------------------------------------------------
// Add Srat tables to the Processor
halMemory = new HalMemorySrat(AcpiTables.GetSrat());
Processor.AddMemory(halMemory);
timer.Start();
// Get the screen resources. Since we have metadata above to
// declare all fixed resources used by the screen,
// YieldResources("") will keep the resource tracking correct:
halScreen = new HalScreenDirect(IoSystem.YieldResources("", typeof(HalScreen)));
Console.Screen = (HalScreen)halScreen;
}
internal static bool Run(PMTimer pmtimer, Timer8254LegacyPC i8254)
{
const int testRuns = 8;
int attempts = 0;
const uint pmMask = 0xffffffu;
const ulong tscMask = 0xffffffffffff;
const int i8254Mask = 0xffff;
ulong [] tscHz = new ulong[testRuns];
ulong [] i8254Hz = new ulong[testRuns];
uint [] pmGoal = new uint[testRuns];
uint [] pmActual = new uint[testRuns];
i8254.Timer2Start();
measure:
attempts++;
for (uint i = 0; i < testRuns; i++)
{
uint testHz = 2u + (i % 5u);
uint pmAccum = 0;
uint pmLast = pmtimer.Value & pmMask;
uint pmEnd = PMTimer.FrequencyHz / testHz;
ulong tscStart = Processor.CycleCount;
ulong tscEnd = 0;
int i8254Accum = 0;
int i8254Last = i8254.Timer2Read();
while (pmAccum < pmEnd)
{
// Spin to burn on few
// clock cycles. On real hardware we stall
// reading the timers. On VPC we see the
// PMTimer go backwards occasionally when
// hammering it so we call SpinWait to
// reduce the chance of observing it go
// backwards.
//
// Note: We explicitly use Thread.SpinWait
// since it will not be optimized out,
// unlike a simple spin loop.
System.Threading.Thread.SpinWait(10000);
uint pmNow = pmtimer.Value & pmMask;
if (pmNow < pmLast)
{
// On VPC the PM
// timer occasionally goes backwards and
// this leads to bogus calibration
// points.
if (pmLast - pmNow < PMTimer.FrequencyHz / 2)
{
// ignore measurement
continue;
}
// Clock wrap, measurement okay.
}
pmAccum += (pmNow + (pmMask + 1) - pmLast) & pmMask;
pmLast = pmNow;
tscEnd = Processor.CycleCount;
int i8254Now = i8254.Timer2Read();
i8254Accum += ((i8254Mask + 1) + i8254Last - i8254Now) &
i8254Mask;
i8254Last = i8254Now;
}
ulong tscDelta = (tscEnd + (tscMask + 1) - tscStart) & tscMask;
tscHz[i] = tscDelta * PMTimer.FrequencyHz / pmAccum;
i8254Hz[i] = (ulong)i8254Accum * PMTimer.FrequencyHz / pmAccum;
pmGoal[i] = pmEnd;
pmActual[i] = pmAccum;
}
#region -*- temporary failure debugging support -*-
ulong[] tscHzBackup = new ulong[tscHz.Length];
ulong[] i8254HzBackup = new ulong[i8254Hz.Length];
Array.Copy(tscHz, tscHzBackup, tscHz.Length);
Array.Copy(i8254Hz, i8254HzBackup, i8254Hz.Length);
#endregion
Array.Sort(tscHz);
Array.Sort(i8254Hz);
bool noisyClock = false;
// Re-measure if values are obviously bogus as can occur with
// VPC. Check is minimum value is less than n% of maximum
// value.
bool tscFailed = tscHz[0] < 3 * tscHz[testRuns - 1] / 4;
bool i8254Failed = i8254Hz[0] < 3 * i8254Hz[testRuns - 1] / 4;
if (tscFailed || i8254Failed)
{
if (attempts < 10)
{
noisyClock = true;
DebugStub.Print("CLOCK CALIBRATION FAILED");
if (tscFailed && i8254Failed)
{
DebugStub.Print(" (tsc and i2854) ");
}
else if (tscFailed)
{
DebugStub.Print(" (tsc only) ");
}
else
{
DebugStub.Print(" (i8254 only) ");
}
DebugStub.Print("RETRYING.\n");
for (int i = 0; i < tscHzBackup.Length; i++)
{
DebugStub.Print("tscHz {0} i8254Hz {1} pmGoal {2} pmActual {3}\n",
__arglist(tscHzBackup[i],
i8254HzBackup[i],
pmGoal[i],
pmActual[i]));
}
goto measure;
}
else
{
DebugStub.Print("ALL CLOCK CALIBRATION ATTEMPTS FAILED.\n");
// TODO:
// Try to calibrate with rtClock
// SlowCalibration(rtClock, timer8254);
Processor.CyclesPerSecond = 1800 * 1000 * 1000;
i8254.SetTicksPerSecond(1193180);
return(true);
}
}
ulong tscHzEstimate = tscHz[MinSpread(tscHz, 3)];
int i8254HzEstimate = (int)i8254Hz[MinSpread(i8254Hz, 3)];
DisplayResults(tscHzEstimate, i8254HzEstimate);
// Set measured frequencies in appropriate places.
Processor.CyclesPerSecond = tscHzEstimate;
i8254.SetTicksPerSecond(i8254HzEstimate);
//
// Range of measurements is a pretty good indicator of VPCness
// since it may have been descheduled during these measurements
// so timer measurements will be poor.
//
int oValue = ApproxLog10(tscHzEstimate);
int oRange = ApproxLog10(tscHz[testRuns - 1] - tscHz[0]);
if (oValue - oRange < 5)
{
DebugStub.Print("*** Noisy timing measurements. Looks like measurement on VPC or bad hardware. ***\n");
noisyClock = true;
}
return(noisyClock);
}
