use 'spin_sleep' for more accurate execution rate, add "s", "m", "u" suffix support to the -C argument

crsn/Cargo.toml

@@ -14,3 +14,4 @@ log = "0.4.11"
 num-traits = "0.2.12"
 parking_lot = "0.11.0"
 nudge = "0.2.1"
+spin_sleep = "1.0.0"

crsn/crsn-sexp/Cargo.toml

@@ -11,4 +11,3 @@ description = "A small, simple, self-contained, s-expression parser and pretty-p
 license = "MIT"
 
 [dependencies]
-log = "0.4.11"

crsn/crsn-sexp/src/lib.rs

@@ -4,9 +4,6 @@
 
 #![deny(unsafe_code)]
 
-#[macro_use]
-extern crate log;
-
 use std::borrow::Cow;
 use std::fmt;
 use std::str::{self, FromStr};

crsn/src/runtime/run_thread.rs

@@ -1,7 +1,7 @@
 use std::sync::Arc;
 
 use std::thread::JoinHandle;
-use std::time::Duration;
+use std::time::{Duration};
 
 pub use info::ThreadInfo;
 pub use state::RunState;
@@ -66,11 +66,16 @@ impl RunThread {
 
     /// Start synchronously
     pub fn run(mut self) {
+        let mut loop_helper = spin_sleep::LoopHelper::builder()
+            .build_with_target_rate(1.0/self.info.cycle_time.as_secs_f64());
+
+        loop_helper.loop_start();
         'run: loop {
             match self.eval_op() {
                 Ok(EvalRes { cycles, advance }) => {
-                    if cycles > 0 {
-                        std::thread::sleep(self.info.cycle_time * (cycles as u32));
+                    for _ in 0..cycles {
+                        loop_helper.loop_sleep();
+                        loop_helper.loop_start();
                     }
                     trace!("Step {}; Status = {}", advance, self.state.frame.status);
                     self.state.frame.pc.advance(advance);