See my answer here:
https://stackoverflow.com/a/37882723/5073786
using Mono.Unix.Native;
namespace drone.StackOverflow{
internal class LinuxHiResTimer {
internal event EventHandler Tick; // Tick event
private System.Diagnostics.Stopwatch watch; // High resolution time
const uint safeDelay = 0; // millisecond (for slightly early wakeup)
private Timespec pendingNanosleepParams = new Timespec();
private Timespec threadNanosleepParams = new Timespec();
object lockObject = new object();
internal long Interval {
get{
double totalNanoseconds;
lock (lockObject) {
totalNanoseconds= (1e9 * pendingNanosleepParams.tv_sec)
+ pendingNanosleepParams.tv_nsec;
}
return (int)(totalNanoseconds * 1e-6);//return value in ms
}
set{
lock (lockObject) {
pendingNanosleepParams.tv_sec = value / 1000;
pendingNanosleepParams.tv_nsec = (long)((value % 1000) * 1e6);//set value in ns
}
}
}
private bool enabled;
internal bool Enabled {
get { return enabled; }
set {
if (value) {
watch.Start();
enabled = value;
Task.Run(()=>tickGenerator()); // fire up new thread
}
else {
lock (lockObject) {
enabled = value;
}
}
}
}
private Task tickGenerator() {
bool bNotPendingStop;
lock (lockObject) {
bNotPendingStop = enabled;
}
while (bNotPendingStop) {
// Check if thread has been told to halt
lock (lockObject) {
bNotPendingStop = enabled;
}
long curTime = watch.ElapsedMilliseconds;
if (curTime >= Interval) {
watch.Restart ();
if (Tick != null)
Tick (this, new EventArgs ());
} else {
long iTimeLeft = (Interval - curTime); // How long to delay for
if (iTimeLeft >= safeDelay) { // Task.Delay has resolution 15ms//await Task.Delay(TimeSpan.FromMilliseconds(iTimeLeft - safeDelay));
threadNanosleepParams.tv_nsec = (int)((iTimeLeft - safeDelay) * 1e6);
threadNanosleepParams.tv_sec = 0;
Syscall.nanosleep (ref threadNanosleepParams, ref threadNanosleepParams);
}
}
}
watch.Stop();
return null;
}
}
Usage:
private myMainFunction(){
LinuxHiResTimer timReallyFast = new LinuxHiResTimer();
timReallyFast.Interval=25; //
timReallyFast.Tick += new EventHandler(timReallyFast_Tick);
timReallyFast.Enabled = true;
}
private void timReallyFast_Tick(System.Object sender, System.EventArgs e) {
// Do this quickly i.e.
PollSerialPort();
}