quanta 0.2.0

high-speed timing facility
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56

use crate::ClockSource;

#[derive(Clone, Default)]
pub struct Counter;

impl Counter {
    #[allow(dead_code)]
    pub fn new() -> Self {
        Counter {}
    }
}

#[cfg(feature = "tsc")]
impl ClockSource for Counter {
    fn now(&self) -> u64 {
        let mut l: u32;
        let mut h: u32;
        unsafe {
            asm!("lfence; rdtsc" : "={eax}" (l), "={edx}" (h) ::: "volatile");
        }
        ((u64::from(h)) << 32) | u64::from(l)
    }

    fn start(&self) -> u64 {
        let mut l: u32;
        let mut h: u32;
        unsafe {
            asm!("lfence; rdtsc; lfence" : "={eax}" (l), "={edx}" (h) ::: "volatile");
        }
        ((u64::from(h)) << 32) | u64::from(l)
    }

    fn end(&self) -> u64 {
        let mut l: u32;
        let mut h: u32;
        unsafe {
            asm!("rdtscp; lfence" : "={eax}" (l), "={edx}" (h) ::: "volatile");
        }
        ((u64::from(h)) << 32) | u64::from(l)
    }
}

#[cfg(not(feature = "tsc"))]
impl ClockSource for Counter {
    fn now(&self) -> u64 {
        panic!("can't use counter without TSC support");
    }

    fn start(&self) -> u64 {
        panic!("can't use counter without TSC support");
    }

    fn end(&self) -> u64 {
        panic!("can't use counter without TSC support");
    }
}