Struct DetTime 

pub struct DetTime { /* private fields */ }

A determinstic notion of time, measuring progress of one thread.

It is based on counting syscalls and conditionals. Ideally it would count instructions, but that is not possible deterministically.

DetTime is a measure of the LOCAL progress of a thread. The notion of global time is defined by aggretion of multiple local times (vector clocks, as in the Kendo algorithm).

Here are a few relevant definitions for deterministic time:

Granularity

How rapidly and consistently does the clock tick with thread progress? A finer notion of deterministic time counts more events (ideally instructions). A coarser notion of deterministic time counts fewer events (like syscalls).

Productivity

In corecursion, or coinductive datatypes like streams, productivity means you can get the next result with finite work. Deterministic time can be viewed a stream of “tick events”. We don’t want a guest thread to be able to do an unbounded amount of work, without a tick occurring. For example, retired branches are a safe bet (any non-trivial amount of work will execute a branch), but system calls are not: a spinning thread can burn cycles forever without executing a syscall.

Implementations

impl DetTime

pub fn new(cfg: &Config) -> Self

Create an initial DetTime respecting a Config

pub fn zero() -> Self

Create a new Dettime which is the earliest possible.

pub fn clone_for_child(&self) -> Self

Inherit an absolute clock for a newly created thread without attributing its ancestors’ work to that thread. Ordinary Clone still copies an existing clock, including its original inheritance, for RPC snapshots.

pub fn inherited_nanos(&self) -> LogicalDuration

Local elapsed time already accounted for by this thread’s ancestors.

pub fn add_syscall(&mut self)

Register that another syscall has executed.

pub fn add_syscall_with_cost(&mut self, nanos: u64)

Register a syscall with its unscaled virtual-time cost in nanoseconds.

pub fn add_rdtsc(&mut self)

Register that an rdtsc intsruction has executed.

pub fn add_cpuid(&mut self)

Register that an cpuid intsruction has executed.

pub fn add_rcbs(&mut self, count: u64)

Update internal counts using the reverie clock value.

pub fn add_rcbs_with_multiplier( &mut self, count: u64, factor: RcbTimeMultiplier, )

Add RCB progress using a deterministic per-thread virtual-time multiplier.

The Q32 accumulator makes the result independent of whether a backend reports the same RCB total in one update or several smaller updates.

pub fn advance_to(&mut self, deadline: LogicalTime)

Advance this local clock to an explicit virtual deadline.

pub fn rcbs(&self) -> u64

Return current rcbs

pub fn as_nanos(&self) -> LogicalTime

Project deterministic logical time into a rough number of nanoseconds.

pub fn without_starting(&self) -> LogicalDuration

Same as as_nanos but without the starting time.

pub fn user_cpu_time(&self) -> LogicalDuration

Guest-execution time that corresponds to user-space instructions.

pub fn system_cpu_time(&self) -> LogicalDuration

Synthetic time charged for intercepted syscall execution.

pub fn as_micros(&self) -> Microseconds

Project deterministic logical time into a rough number of microseconds.

pub fn with_multiplier(self, m: f64) -> Self

Set the clock multiplier

pub fn as_duration(&self) -> Duration

Project deterministic time duration from imaginary starting point of deterministic time creation

Trait Implementations

impl Clone for DetTime

fn clone(&self) -> Self

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for DetTime

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for DetTime

fn default() -> Self

Returns the “default value” for a type.

impl<'de> Deserialize<'de> for DetTime

fn deserialize<__D>(__deserializer: __D) -> Result<Self, __D::Error>

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl Eq for DetTime

impl From<&DateTime<Utc>> for DetTime

fn from(dt: &DateTime<Utc>) -> Self

Converts to this type from the input type.

impl Into<Timespec> for DetTime

fn into(self) -> Timespec

Converts this type into the (usually inferred) input type.

impl Ord for DetTime

DetTime behaves as a totally ordered scalar.

fn cmp(&self, other: &Self) -> Ordering

This method returns an Ordering between self and other.

fn max(self, other: Self) -> Self

where Self: Sized,

Compares and returns the maximum of two values.

fn min(self, other: Self) -> Self

where Self: Sized,

Compares and returns the minimum of two values.

fn clamp(self, min: Self, max: Self) -> Self

where Self: Sized,

Restrict a value to a certain interval.

fn clamp_to<R>(self, range: R) -> Self

where Self: Sized, R: ClampBounds<Self>,

🔬This is a nightly-only experimental API. (clamp_to)

Restrict a value to a certain range.

impl PartialEq for DetTime

fn eq(&self, other: &Self) -> bool

Equality operator ==.

fn ne(&self, other: &Rhs) -> bool

Inequality operator !=.

impl PartialOrd for DetTime

fn partial_cmp(&self, other: &Self) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

fn lt(&self, other: &Rhs) -> bool

Tests less than (for self and other) and is used by the < operator.

fn le(&self, other: &Rhs) -> bool

Tests less than or equal to (for self and other) and is used by the <= operator.

fn gt(&self, other: &Rhs) -> bool

Tests greater than (for self and other) and is used by the > operator.

fn ge(&self, other: &Rhs) -> bool

Tests greater than or equal to (for self and other) and is used by the >= operator.

impl Serialize for DetTime

fn serialize<__S>(&self, __serializer: __S) -> Result<__S::Ok, __S::Error>

where __S: Serializer,

Serialize this value into the given Serde serializer.