From 72afd7af6c31fb5bef01a65a4454f7873c34273d Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Marcel=20M=C3=A4rtens?= <marcel.cochem@googlemail.com>
Date: Tue, 10 Nov 2020 22:39:10 +0100
Subject: [PATCH] switch to `spin_sleep`

---
 Cargo.lock          | 11 +++++++++++
 common/Cargo.toml   |  1 +
 common/src/clock.rs | 30 +-----------------------------
 3 files changed, 13 insertions(+), 29 deletions(-)

diff --git a/Cargo.lock b/Cargo.lock
index ecddda7a45..42287b4056 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -4091,6 +4091,16 @@ version = "0.5.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "6e63cff320ae2c57904679ba7cb63280a3dc4613885beafb148ee7bf9aa9042d"
 
+[[package]]
+name = "spin_sleep"
+version = "1.0.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2a98101bdc3833e192713c2af0b0dd2614f50d1cf1f7a97c5221b7aac052acc7"
+dependencies = [
+ "once_cell",
+ "winapi 0.3.9",
+]
+
 [[package]]
 name = "static_assertions"
 version = "1.1.0"
@@ -4887,6 +4897,7 @@ dependencies = [
  "slab",
  "specs",
  "specs-idvs",
+ "spin_sleep",
  "sum_type",
  "tracing",
  "tracy-client",
diff --git a/common/Cargo.toml b/common/Cargo.toml
index ee17816cd4..46eee67fae 100644
--- a/common/Cargo.toml
+++ b/common/Cargo.toml
@@ -38,6 +38,7 @@ sum_type = "0.2.0"
 authc = { git = "https://gitlab.com/veloren/auth.git", rev = "b943c85e4a38f5ec60cd18c34c73097640162bfe" }
 slab = "0.4.2"
 enum-iterator = "0.6"
+spin_sleep = "1.0"
 num-traits = "0.2"
 num-derive = "0.3"
 
diff --git a/common/src/clock.rs b/common/src/clock.rs
index 39e0acefec..bcdf398f8c 100644
--- a/common/src/clock.rs
+++ b/common/src/clock.rs
@@ -1,7 +1,6 @@
 use crate::span;
 use std::{
     collections::VecDeque,
-    thread,
     time::{Duration, Instant},
 };
 
@@ -84,7 +83,7 @@ impl Clock {
 
         // Attempt to sleep to fill the gap.
         if let Some(sleep_dur) = self.target_dt.checked_sub(busy_delta) {
-            Clock::sleep(current_sys_time, sleep_dur)
+            spin_sleep::sleep(sleep_dur);
         }
 
         let after_sleep_sys_time = Instant::now();
@@ -97,33 +96,6 @@ impl Clock {
         self.total_tick_time += self.last_dt;
         self.last_sys_time = after_sleep_sys_time;
     }
-
-    /// try to do a high precision sleep.
-    /// When this `fn` returns it SHOULD be before+dur as accurate is possible.
-    /// Returns the after sleep Instant.
-    fn sleep(before: Instant, dur: Duration) {
-        const BUSY_WAITING_TRIGGER_DUR: Duration = Duration::from_millis(2);
-        #[cfg(not(windows))]
-        const BUSY_WAITING_TIME: Duration = Duration::from_nanos(125_000);
-        #[cfg(windows)]
-        const BUSY_WAITING_TIME: Duration = Duration::from_nanos(500_000);
-
-        // If we have more than BUSY_TRIGGER_DUR on our sleep bucket, do sleep for
-        // (1-BUSY_WAITING_TIME) time and do some busy waiting. If we are on high load,
-        // don't try such fancy precision increasing
-        if dur > BUSY_WAITING_TRIGGER_DUR {
-            let first_sleep_dur = dur - BUSY_WAITING_TIME;
-            thread::sleep(first_sleep_dur);
-            let target_time = before + dur;
-            span!(_guard, "tick", "Clock::busy_wait");
-            while target_time > Instant::now() {
-                //busy waiting
-                std::sync::atomic::spin_loop_hint();
-            }
-        } else {
-            thread::sleep(dur);
-        }
-    }
 }
 
 impl ClockStats {