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SITL: use more granrular sleeps for windows

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This commit is contained in:
Andrew Tridgell 2015-05-25 16:48:13 +10:00
parent 320b69c375
commit 2b2259a6d7
3 changed files with 45 additions and 18 deletions
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58
libraries/SITL/SIM_Aircraft.cpp
View File

@ -24,6 +24,11 @@
#include <unistd.h>
#include <sys/time.h>
#include <stdio.h>
#ifdef __CYGWIN__
#include <windows.h>
#include <time.h>
#include <Mmsystem.h>
#endif
/*
parent class for all simulator types
@ -45,7 +50,8 @@ Aircraft::Aircraft(const char *home_str, const char *frame_str) :
accel_noise(0.3),
rate_hz(400),
last_time_us(0),
autotest_dir(NULL)
autotest_dir(NULL),
min_sleep_time(20000)
{
char *saveptr=NULL;
char *s = strdup(home_str);
@ -135,28 +141,31 @@ void Aircraft::adjust_frame_time(float new_rate)
scaled_frame_time_us = frame_time_us/target_speedup;
}
/* try to synchronise simulation time with wall clock time, taking
into account desired speedup */
/*
try to synchronise simulation time with wall clock time, taking
into account desired speedup
This tries to take account of possible granularity of
get_wall_time_us() so it works reasonably well on windows
*/
void Aircraft::sync_frame_time(void)
{
frame_counter++;
uint64_t now = get_wall_time_us();
uint64_t dt_us = now - last_wall_time_us;
if (dt_us < scaled_frame_time_us) {
usleep(scaled_frame_time_us - dt_us);
now = get_wall_time_us();
if (now > last_wall_time_us && now - last_wall_time_us < 1.0e5) {
float rate = 1.0e6f/(now - last_wall_time_us);
achieved_rate_hz = (0.98f*achieved_rate_hz) + (0.02f*rate);
if (achieved_rate_hz < rate_hz * target_speedup) {
scaled_frame_time_us *= 0.999;
} else {
scaled_frame_time_us *= 1.001;
}
if (frame_counter >= 10 && now > last_wall_time_us) {
float rate = frame_counter * 1.0e6f/(now - last_wall_time_us);
achieved_rate_hz = (0.98f*achieved_rate_hz) + (0.02f*rate);
if (achieved_rate_hz < rate_hz * target_speedup) {
scaled_frame_time_us *= 0.99;
} else {
scaled_frame_time_us *= 1.01;
}
uint32_t sleep_time = scaled_frame_time_us*frame_counter;
if (sleep_time >= min_sleep_time) {
usleep(scaled_frame_time_us*frame_counter);
}
last_wall_time_us = now;
frame_counter = 0;
}
last_wall_time_us = now;
}
/* add noise based on throttle level (from 0..1) */
@ -239,9 +248,22 @@ void Aircraft::fill_fdm(struct sitl_fdm &fdm) const
uint64_t Aircraft::get_wall_time_us() const
{
#ifdef __CYGWIN__
static DWORD tPrev;
static uint64_t last_ret_us;
if (tPrev == 0) {
tPrev = timeGetTime();
return 0;
}
DWORD now = timeGetTime();
last_ret_us += (uint64_t)((now - tPrev)*1000UL);
tPrev = now;
return last_ret_us;
#else
struct timeval tp;
gettimeofday(&tp,NULL);
return tp.tv_sec*1.0e6 + tp.tv_usec;
#endif
}
/*

2
libraries/SITL/SIM_Aircraft.h
View File

@ -131,6 +131,8 @@ protected:
private:
uint64_t last_time_us;
uint32_t frame_counter;
const uint32_t min_sleep_time;
};
#endif // _SIM_AIRCRAFT_H

3
mk/board_native.mk
View File

@ -41,6 +41,9 @@ LDFLAGS += -Wl,--gc-sections -Wl,-Map -Wl,$(SKETCHMAP)
endif
LIBS ?= -lm -lpthread
ifneq ($(findstring CYGWIN, $(SYSTYPE)),)
LIBS += -lwinmm
endif
ifeq ($(VERBOSE),)
v = @