BizHawk/BizHawk.Client.EmuHawk/Throttle.cs

393 lines
10 KiB
C#

using System;
using System.Diagnostics;
using System.Runtime.InteropServices;
using System.Threading;
using BizHawk.Client.Common;
//this throttle is nitsuja's fine-tuned techniques from desmume
namespace BizHawk.Client.EmuHawk
{
public class Throttle
{
int lastskiprate;
int framestoskip;
int framesskipped;
public bool skipnextframe;
//if the emulator is paused then we dont need to behave as if unthrottled
public bool signal_paused;
public bool signal_frameAdvance;
public bool signal_unthrottle;
public bool signal_continuousframeAdvancing; //continuousframeAdvancing
public bool signal_overrideSecondaryThrottle;
public int cfg_frameskiprate
{
get
{
return Global.Config.FrameSkip;
}
}
public bool cfg_frameLimit
{
get
{
return Global.Config.ClockThrottle;
}
}
public bool cfg_autoframeskipenab
{
get
{
return Global.Config.AutoMinimizeSkipping;
}
}
public void Step(bool allowSleep, int forceFrameSkip)
{
//TODO - figure out what allowSleep is supposed to be used for
//TODO - figure out what forceFrameSkip is supposed to be used for
bool extraThrottle = false;
//if we're paused, none of this should happen. just clean out our state and dont skip
//notably, if we're frame-advancing, we should be paused.
if (signal_paused && !signal_continuousframeAdvancing)
{
//Console.WriteLine("THE THING: {0} {1}", signal_paused ,signal_continuousframeAdvancing);
skipnextframe = false;
framesskipped = 0;
framestoskip = 0;
//keep from burning CPU
Thread.Sleep(10);
return;
}
//heres some ideas for how to begin cleaning this up
////at this point, its assumed that we're running.
////this could be a free run, an unthrottled run, or a 'continuous frame advance' (aka continuous) run
////free run: affected by frameskips and throttles
////unthrottled run: affected by frameskips only
////continuous run: affected by frameskips and throttles
////so continuous and free are the same?
//bool continuous_run = signal_continuousframeAdvancing;
//bool unthrottled_run = signal_unthrottle;
//bool free_run = !continuous_run && !unthrottled_run;
//bool do_throttle, do_skip;
//if (continuous_run || free_run)
// do_throttle = do_skip = true;
//else if (unthrottled_run)
// do_skip = true;
//else throw new InvalidOperationException();
int skipRate = (forceFrameSkip < 0) ? cfg_frameskiprate : forceFrameSkip;
int ffSkipRate = (forceFrameSkip < 0) ? 3 : forceFrameSkip;
if (lastskiprate != skipRate)
{
lastskiprate = skipRate;
framestoskip = 0; // otherwise switches to lower frameskip rates will lag behind
}
if (!skipnextframe || forceFrameSkip == 0 || (signal_continuousframeAdvancing && !signal_unthrottle))
{
framesskipped = 0;
if (signal_continuousframeAdvancing)
{
//dont ever skip frames when continuous frame advancing. it's meant for precision work.
//but we DO need to throttle
if(Global.Config.ClockThrottle)
extraThrottle = true;
}
else
{
if (framestoskip > 0)
skipnextframe = true;
}
}
else
{
framestoskip--;
if (framestoskip < 1)
skipnextframe = false;
else
skipnextframe = true;
framesskipped++;
}
if (signal_unthrottle)
{
if (framesskipped < ffSkipRate)
{
skipnextframe = true;
framestoskip = 1;
}
if (framestoskip < 1)
framestoskip += ffSkipRate;
}
else if ((extraThrottle || signal_paused || /*autoframeskipenab && frameskiprate ||*/ cfg_frameLimit || signal_overrideSecondaryThrottle) && allowSleep)
{
SpeedThrottle(signal_paused);
}
if (cfg_autoframeskipenab && cfg_frameskiprate != 0)
{
if (!signal_continuousframeAdvancing)
{
AutoFrameSkip_NextFrame();
if (framestoskip < 1)
framestoskip += AutoFrameSkip_GetSkipAmount(0, skipRate);
}
}
else
{
if (framestoskip < 1)
framestoskip += skipRate;
}
}
static ulong GetCurTime()
{
if (tmethod == 1)
return (ulong)Stopwatch.GetTimestamp();
else
return (ulong)Environment.TickCount;
}
#if WINDOWS
[DllImport("winmm.dll", EntryPoint = "timeBeginPeriod")]
static extern uint timeBeginPeriod(uint uMilliseconds);
#endif
static readonly int tmethod;
static readonly ulong afsfreq;
static readonly ulong tfreq;
static Throttle()
{
#if WINDOWS
timeBeginPeriod(1);
#endif
if (Stopwatch.IsHighResolution)
{
afsfreq = (ulong)Stopwatch.Frequency;
tmethod = 1;
}
else
{
afsfreq = 1000;
tmethod = 0;
}
Console.WriteLine("throttle method: {0}; resolution: {1}", tmethod, afsfreq);
tfreq = afsfreq * 65536;
}
public void SetCoreFps(double desired_fps)
{
core_desiredfps = (ulong)(65536 * desired_fps);
int target_pct = pct;
pct = -1;
SetSpeedPercent(target_pct);
}
int pct = -1;
public void SetSpeedPercent(int percent)
{
//Console.WriteLine("throttle set percent " + percent);
if (pct == percent) return;
pct = percent;
float fraction = percent / 100.0f;
desiredfps = (ulong)(core_desiredfps * fraction);
//Console.WriteLine("throttle set desiredfps " + desiredfps);
desiredspf = 65536.0f / desiredfps;
AutoFrameSkip_IgnorePreviousDelay();
}
ulong core_desiredfps;
ulong desiredfps;
float desiredspf;
ulong ltime;
ulong beginticks, endticks, preThrottleEndticks;
float fSkipFrames;
float fSkipFramesError;
int lastSkip;
float lastError;
float integral;
public void AutoFrameSkip_IgnorePreviousDelay()
{
beginticks = GetCurTime();
// this seems to be a stable way of allowing the skip frames to
// quickly adjust to a faster environment (e.g. after a loadstate)
// without causing oscillation or a sudden change in skip rate
fSkipFrames *= 0.5f;
}
void AutoFrameSkip_BeforeThrottle()
{
preThrottleEndticks = GetCurTime();
}
void AutoFrameSkip_NextFrame()
{
endticks = GetCurTime();
// calculate time since last frame
ulong diffticks = Math.Max(endticks - beginticks, 1);
float diff = (float)diffticks / afsfreq;
// calculate time since last frame not including throttle sleep time
if (preThrottleEndticks == 0) // if we didn't throttle, use the non-throttle time
preThrottleEndticks = endticks;
ulong diffticksUnthrottled = preThrottleEndticks - beginticks;
float diffUnthrottled = (float)diffticksUnthrottled / afsfreq;
float error = diffUnthrottled - desiredspf;
// reset way-out-of-range values
if (diff > 1)
diff = 1;
if (error > 1 || error < -1)
error = 0;
if (diffUnthrottled > 1)
diffUnthrottled = desiredspf;
float derivative = (error - lastError) / diff;
lastError = error;
integral = integral + (error * diff);
integral *= 0.99f; // since our integral isn't reliable, reduce it to 0 over time.
// "PID controller" constants
// this stuff is probably being done all wrong, but these seem to work ok
const float Kp = 40.0f;
const float Ki = 0.55f;
const float Kd = 0.04f;
float errorTerm = error * Kp;
float derivativeTerm = derivative * Kd;
float integralTerm = integral * Ki;
float adjustment = errorTerm + derivativeTerm + integralTerm;
// apply the output adjustment
fSkipFrames += adjustment;
// if we're running too slowly, prevent the throttle from kicking in
if (adjustment > 0 && fSkipFrames > 0)
ltime -= tfreq / desiredfps;
preThrottleEndticks = 0;
beginticks = GetCurTime();
}
int AutoFrameSkip_GetSkipAmount(int min, int max)
{
int rv = (int)fSkipFrames;
fSkipFramesError += fSkipFrames - rv;
// resolve accumulated fractional error
// where doing so doesn't push us out of range
while (fSkipFramesError >= 1.0f && rv <= lastSkip && rv < max)
{
fSkipFramesError -= 1.0f;
rv++;
}
while (fSkipFramesError <= -1.0f && rv >= lastSkip && rv > min)
{
fSkipFramesError += 1.0f;
rv--;
}
// restrict skip amount to requested range
if (rv < min)
rv = min;
if (rv > max)
rv = max;
// limit maximum error accumulation (it's mainly only for fractional components)
if (fSkipFramesError >= 4.0f)
fSkipFramesError = 4.0f;
if (fSkipFramesError <= -4.0f)
fSkipFramesError = -4.0f;
// limit ongoing skipframes to requested range + 1 on each side
if (fSkipFrames < min - 1)
fSkipFrames = (float)min - 1;
if (fSkipFrames > max + 1)
fSkipFrames = (float)max + 1;
// printf("%d", rv);
lastSkip = rv;
return rv;
}
void SpeedThrottle(bool paused)
{
AutoFrameSkip_BeforeThrottle();
ulong timePerFrame = tfreq / desiredfps;
while (true)
{
if (signal_unthrottle)
return;
ulong ttime = GetCurTime();
ulong elapsedTime = ttime - ltime;
if (elapsedTime >= timePerFrame)
{
int maxMissedFrames = (int)Math.Ceiling((Global.SoundMaxBufferDeficitMs / 1000.0) / ((double)timePerFrame / afsfreq));
if (maxMissedFrames < 3)
maxMissedFrames = 3;
if (elapsedTime > timePerFrame * (ulong)(1 + maxMissedFrames))
ltime = ttime;
else
ltime += timePerFrame;
return;
}
int sleepTime = (int)((timePerFrame - elapsedTime) * 1000 / afsfreq);
if (sleepTime >= 2 || paused)
{
#if WINDOWS
// Assuming a timer period of 1 ms (i.e. timeBeginPeriod(1)): The actual sleep time
// on Windows XP is generally within a half millisecond either way of the requested
// time. The actual sleep time on Windows 8 is generally between the requested time
// and up to a millisecond over. So we'll subtract 1 ms from the time to avoid
// sleeping longer than desired.
sleepTime -= 1;
#else
// The actual sleep time on OS X with Mono is generally between the request time
// and up to 25% over. So we'll scale the sleep time back to account for that.
sleepTime = sleepTime * 4 / 5;
#endif
Thread.Sleep(Math.Max(sleepTime, 1));
}
else if (sleepTime > 0) // spin for <1 millisecond waits
{
Thread.Yield(); // limit to other threads on the same CPU core for other short waits
}
}
}
}
}