gwr_engine/time/
simtime.rs

1// Copyright (c) 2023 Graphcore Ltd. All rights reserved.
2
3//! This module represents the time during a simulation.
4//!
5//! Time is made up of a cycle count and a phase.
6
7use std::rc::Rc;
8
9use gwr_track::entity::Entity;
10use gwr_track::set_time;
11
12use super::clock::Clock;
13use crate::time::clock::TaskWaker;
14
15/// The overall owner of time within a simulation.
16///
17/// Contains all Clocks and the current simulation time in ns.
18#[derive(Clone)]
19pub struct SimTime {
20    entity: Rc<Entity>,
21
22    current_ns: f64,
23
24    /// Clocks are auto-created as required and kept in a HashMap.
25    ///
26    /// They are hashed using a `u64` which is done in `Hz` so there is a chance
27    /// that a certain clock f
28    clocks: Vec<Clock>,
29}
30
31impl SimTime {
32    #[must_use]
33    pub fn new(parent: &Rc<Entity>) -> Self {
34        Self {
35            entity: Rc::new(Entity::new(parent, "time")),
36            current_ns: 0.0,
37            clocks: Vec::new(),
38        }
39    }
40
41    pub fn get_clock(&mut self, freq_mhz: f64) -> Clock {
42        for clock in &self.clocks {
43            if clock.freq_mhz() == freq_mhz {
44                return clock.clone();
45            }
46        }
47        let clock = Clock::new(freq_mhz);
48        self.clocks.push(clock.clone());
49        clock
50    }
51
52    /// Choose the clock with the next time and return the associated Waker.
53    pub fn advance_time(&mut self) -> Option<Vec<TaskWaker>> {
54        if let Some(next_clock) = self.clocks.iter().min_by(|a, b| a.cmp(b)) {
55            if let Some(clock_time) = next_clock.shared_state.waiting_times.borrow_mut().pop() {
56                let next_ns = next_clock.to_ns(&clock_time);
57                if self.current_ns != next_ns {
58                    set_time!(self.entity ; next_ns);
59                    self.current_ns = next_ns;
60                }
61                next_clock.advance_time(clock_time);
62                next_clock.shared_state.waiting.borrow_mut().pop()
63            } else {
64                None
65            }
66        } else {
67            None
68        }
69    }
70
71    #[must_use]
72    pub fn time_now_ns(&self) -> f64 {
73        self.current_ns
74    }
75
76    /// The simulation can exit if all scheduled tasks can exit.
77    #[must_use]
78    pub fn can_exit(&self) -> bool {
79        for clock in &self.clocks {
80            for waiting in clock.shared_state.waiting.borrow().iter() {
81                for task_waker in waiting {
82                    if !task_waker.can_exit {
83                        // Found one task that must be completed
84                        return false;
85                    }
86                }
87            }
88        }
89        true
90    }
91}
92
93#[cfg(test)]
94mod tests {
95    use gwr_track::entity::toplevel;
96    use gwr_track::test_helpers::create_tracker;
97
98    use super::*;
99
100    #[test]
101    fn clock_created_once() {
102        let tracker = create_tracker(file!());
103        let top = toplevel(&tracker, "top");
104
105        let mut time = SimTime::new(&top);
106        let _clk1 = time.get_clock(1000.0);
107        assert_eq!(time.clocks.len(), 1);
108
109        let _clk2 = time.get_clock(1000.0);
110        assert_eq!(time.clocks.len(), 1);
111    }
112
113    #[test]
114    fn create_different_clocks() {
115        let tracker = create_tracker(file!());
116        let top = toplevel(&tracker, "top");
117
118        let mut time = SimTime::new(&top);
119        let _clk1 = time.get_clock(1000.0);
120        assert_eq!(time.clocks.len(), 1);
121
122        let _clk2 = time.get_clock(1800.0);
123        assert_eq!(time.clocks.len(), 2);
124    }
125}
gwr_engine/time/simtime.rs

gwr_engine/time/
simtime.rs
