reworking thread timing

This commit is contained in:
Jorj Bauer 2020-07-12 00:40:11 -04:00
parent db39f6e5b7
commit 7831feeecf
2 changed files with 111 additions and 91 deletions

View File

@ -37,6 +37,7 @@ namespace arduino_preprocessor_is_buggy {
Threads::Scope locker(getSerialLock()); Threads::Scope locker(getSerialLock());
silence(expand{ (print_fwd(params), 42)... }); silence(expand{ (print_fwd(params), 42)... });
Serial.println(); Serial.println();
Serial.flush();
} }
} }

View File

@ -16,6 +16,8 @@
#include "teensy-prefs.h" #include "teensy-prefs.h"
#include "teensy-println.h" #include "teensy-println.h"
//#define DEBUG_TIMING
#if F_CPU < 240000000 #if F_CPU < 240000000
#pragma AiiE warning: performance will improve if you overclock the Teensy to 240MHz (F_CPU=240MHz) or 256MHz (F_CPU=256MHz) #pragma AiiE warning: performance will improve if you overclock the Teensy to 240MHz (F_CPU=240MHz) or 256MHz (F_CPU=256MHz)
#endif #endif
@ -170,7 +172,7 @@ void setup()
Serial.flush(); Serial.flush();
threads.setMicroTimer(); // use a 100uS timer instead of a 1mS timer threads.setMicroTimer(); // use a 100uS timer instead of a 1mS timer
threads.setSliceMicros(5); // threads.setSliceMicros(5);
cpuThreadId = threads.addThread(runCPU); cpuThreadId = threads.addThread(runCPU);
displayThreadId = threads.addThread(runDisplay); displayThreadId = threads.addThread(runDisplay);
maintenanceThreadId = threads.addThread(runMaintenance); maintenanceThreadId = threads.addThread(runMaintenance);
@ -183,9 +185,9 @@ void setup()
// of noise. It's not ideal, but it proves that it's possible; using a real SPI // of noise. It's not ideal, but it proves that it's possible; using a real SPI
// DAC here would probably work. // DAC here would probably work.
threads.setTimeSlice(displayThreadId, 40); threads.setTimeSlice(displayThreadId, 40);
threads.setTimeSlice(cpuThreadId, 10); threads.setTimeSlice(cpuThreadId, 20);
threads.setTimeSlice(maintenanceThreadId, 1); threads.setTimeSlice(maintenanceThreadId, 1);
threads.setTimeSlice(speakerThreadId, 10); // guessing at a good value threads.setTimeSlice(speakerThreadId, 20); // guessing at a good value
} }
// FIXME: move these memory-related functions elsewhere... // FIXME: move these memory-related functions elsewhere...
@ -264,28 +266,48 @@ void biosInterrupt()
void runSpeaker() void runSpeaker()
{ {
uint32_t nextRuntime = 0; uint32_t nextResetMillis = 0;
while (1) { uint32_t refreshCount = 0;
if (micros() > nextRuntime) { uint32_t microsAtStart = 0;
Threads::Scope lock(speakerlock); uint32_t microsForNext = micros() + 1000000/SAMPLERATE; // (1000000 us/second) / (frames/second) = us/frame
digitalWrite(DEBUGPIN, HIGH);
digitalWrite(DEBUGPIN, LOW); while (1) {
if (micros() >= microsForNext) {
refreshCount++;
microsForNext = microsAtStart + ((1000000*refreshCount)/SAMPLERATE);
{
Threads::Scope lock(speakerlock);
nextRuntime = micros() + ((float)1000000/(float)SAMPLERATE); // 125 uS per cycle @ 8k sample rate
((TeensySpeaker *)g_speaker)->maintainSpeaker(); ((TeensySpeaker *)g_speaker)->maintainSpeaker();
}
} else { } else {
while (micros() < microsForNext)
threads.yield(); threads.yield();
} }
if (millis() >= nextResetMillis) {
nextResetMillis = millis() + 1000;
#ifdef DEBUG_TIMING
static char buf[25];
float pct = (100.0 * (float)refreshCount) / (float)SAMPLERATE;
sprintf(buf, "Speaker running at %f%%", pct);
println(buf);
#endif
refreshCount = 0;
microsAtStart = micros();
microsForNext = microsAtStart + ((1000000*refreshCount)/SAMPLERATE);
}
} }
} }
// FIXME: how often does this really need to run? We can threads.yield() when we're running too quickly
void runMaintenance() void runMaintenance()
{ {
uint32_t nextRuntime = 0; uint32_t nextRuntime = 0;
while (1) { while (1) {
if (millis() > nextRuntime) { if (millis() >= nextRuntime) {
nextRuntime = millis() + 100; // FIXME: what's a good time here nextRuntime = millis() + 100; // FIXME: what's a good time here
if (biosThreadId == -1) { if (biosThreadId == -1) {
@ -304,25 +326,36 @@ void runMaintenance()
g_keyboard->maintainKeyboard(); g_keyboard->maintainKeyboard();
usb.maintain(); usb.maintain();
} else { } else {
threads.delay(10); while (millis() < nextRuntime)
// threads.yield(); threads.yield();
} }
} }
} }
// FIXME: figure out how to limit this to 30 FPS (or whatver) so we can #define TARGET_FPS 30
// appropriately use threads.yield()
void runDisplay() void runDisplay()
{ {
g_display->redraw(); // Redraw the UI; don't blit to the physical device g_display->redraw(); // Redraw the UI; don't blit to the physical device
// When do we want to reset our expectation of "normal"?
uint32_t nextResetMillis = 0;
// how many full display refreshes have we managed in this second?
uint32_t refreshCount = 0;
// how many micros until the next frame refresh?
uint32_t microsAtStart = 0;
uint32_t microsForNext = micros() + 1000000/TARGET_FPS; // (1000000 us/second) / (frames/second) = us/frame
uint32_t lastFps = 0;
while (1) { while (1) {
// If it's time to draw the next frame, then do so
if (micros() >= microsForNext) {
refreshCount++;
microsForNext = microsAtStart + ((1000000*refreshCount)/TARGET_FPS);
{ {
Threads::Scope lock(displaylock); Threads::Scope lock(displaylock);
doDebugging(); doDebugging(lastFps);
uint32_t startDisp = millis();
uint32_t cpuBefore = g_cpu->cycles;
g_ui->blit(); g_ui->blit();
g_vm->vmdisplay->lockDisplay(); g_vm->vmdisplay->lockDisplay();
if (g_vm->vmdisplay->needsRedraw()) { // necessary for the VM to redraw if (g_vm->vmdisplay->needsRedraw()) { // necessary for the VM to redraw
@ -334,64 +367,60 @@ void runDisplay()
} }
g_display->blit(); // Blit the whole thing, including UI area g_display->blit(); // Blit the whole thing, including UI area
g_vm->vmdisplay->unlockDisplay(); g_vm->vmdisplay->unlockDisplay();
uint32_t dispTime = millis() - startDisp;
uint32_t cpuAfter = g_cpu->cycles;
if (dispTime > 75) {
print("Slow blit: ");
print(dispTime);
print(" cpu ran: ");
println(cpuAfter - cpuBefore);
} }
} else {
// We're running faster than needed, so give other threads some time
while (micros() < microsForNext)
threads.yield();
}
// Once a second, start counting all over again
if (millis() >= nextResetMillis) {
lastFps = refreshCount;
#ifdef DEBUG_TIMING
println("Display running at ", lastFps, " FPS");
#endif
nextResetMillis = millis() + 1000;
refreshCount = 0;
microsAtStart = micros();
microsForNext = microsAtStart + ((1000000*refreshCount)/TARGET_FPS);
} }
} }
} }
void runCPU() void runCPU()
{ {
uint32_t nextInstructionMicros; uint32_t nextResetMillis = 0;
uint32_t startMicros; uint32_t countSinceLast = 0;
startMicros = nextInstructionMicros = micros(); uint32_t microsAtStart = micros();
uint32_t microsForNext = microsAtStart + (countSinceLast * SPEEDCTL);
uint32_t startMillis = millis();
while (1) { while (1) {
// Relatively critical timing: CPU needs to run ahead at least 4 if (micros() >= microsForNext) {
// cycles, b/c we're calling this interrupt (runCPU, that is) just
// about 1/3 as fast as we should; and the speaker is updated
// directly from within it, so it needs to be real-ish time.
if (micros() >= nextInstructionMicros) {
uint32_t expectedCycles = (micros() - startMicros) * SPEEDCTL;
uint8_t executed;
cpulock.lock(); // Blocking; if the BIOS is running, we stall here cpulock.lock(); // Blocking; if the BIOS is running, we stall here
executed = g_cpu->Run(24); countSinceLast += g_cpu->Run(24); // The CPU runs in bursts of cycles. This '24' is the max burst we perform.
((AppleVM *)g_vm)->cpuMaintenance(g_cpu->cycles);
cpulock.unlock(); cpulock.unlock();
// The CPU of the Apple //e ran at 1.023 MHz. Adjust when we think microsForNext = microsAtStart + (countSinceLast * SPEEDCTL);
// the next instruction should run based on how long the execution
// was ((1000/1023) * numberOfCycles) - which is about 97.8%.
if (expectedCycles > g_cpu->cycles) {
nextInstructionMicros = micros();
#if 1
// show a warning on serial about our current performance
double percentage = ((double)g_cpu->cycles / (double)expectedCycles) * 100.0;
static uint32_t nextWarningTime = 0;
if (millis() > nextWarningTime) {
static char buf[100];
sprintf(buf, "CPU running at %f%% of %d", percentage, g_speed);
println(buf);
nextWarningTime = millis() + 1000;
}
#endif
} else { } else {
nextInstructionMicros = startMicros + ((double)g_cpu->cycles * (double)SPEEDCTL); while (micros() < microsForNext)
threads.yield();
} }
((AppleVM *)g_vm)->cpuMaintenance(g_cpu->cycles); if (millis() >= nextResetMillis) {
} else { nextResetMillis = millis() + 1000;
threads.yield(); #ifdef DEBUG_TIMING
// threads.delay(1); static char buf[25];
float pct = (100.0 * (float)countSinceLast) / (float)g_speed;
sprintf(buf, "CPU running at %f%%", pct);
println(buf);
#endif
countSinceLast = 0;
microsAtStart = micros();
microsForNext = microsAtStart + (countSinceLast * SPEEDCTL);
} }
} }
} }
@ -405,23 +434,13 @@ void loop()
} }
} }
void doDebugging() void doDebugging(uint32_t lastFps)
{ {
char buf[25]; char buf[25];
switch (g_debugMode) { switch (g_debugMode) {
case D_SHOWFPS: case D_SHOWFPS:
// display some FPS data sprintf(buf, "%lu FPS", lastFps);
static uint32_t startAt = millis();
static uint32_t loopCount = 0;
loopCount++;
time_t lenSecs;
lenSecs = (millis() - startAt) / 1000;
if (lenSecs >= 5) {
sprintf(buf, "%lu FPS", loopCount / lenSecs);
g_display->debugMsg(buf); g_display->debugMsg(buf);
startAt = millis();
loopCount = 0;
}
break; break;
case D_SHOWMEMFREE: case D_SHOWMEMFREE:
sprintf(buf, "%lu %u", FreeRamEstimate(), heapSize()); sprintf(buf, "%lu %u", FreeRamEstimate(), heapSize());