Timing

The following variables, functions and classes are all defined within the namespace HIPP.

Ticker

class Ticker

Ticker is used for timing and recording events, and producing summary statistics of them.

Ticker is copyable and movable. The copy is deep - new object is independent to the old object that gets copied. The move is destructive - old object cannot be used after being moved.

typedef std::chrono::steady_clock clock_t

typedef clock_t::time_point point_t

typedef std::chrono::duration<double> dur_t

typedef std::size_t index_t

Typedefs.

clock_t : clock type for timing.

point_t : time point used internally by the clock.

dur_t : duration of event used by Ticker.

index_t : index of the recorded events.

struct record_t

Type used by Ticker to record each event.

dur_t dur

string rec_str

Duration and message string of this event.

Times are in seconds.

record_t(const dur_t &d, const string &r)

ostream &info(ostream &os = cout, int fmt_cntl = 1) const

friend ostream &operator<<(ostream &os, const record_t &r)

Print the record. fmt_cntl is not significant in the current implementation.

operator<<() is equivalent to info() with default fmt_cntl.

struct summary_t

Summary information of all recorded events.

index_t n_recs

double dur_total

double dur_mean

double dur_sd

Number of records, total time elapsed, mean time elapsed and standard deviation of them.

Times are in seconds.

ostream &info(ostream &os = cout, int fmt_cntl = 1) const

friend ostream &operator<<(ostream &os, const summary_t &s)

Print the summary statistics. fmt_cntl is not significant in the current implementation.

operator<<() is equivalent to info() with default fmt_cntl.

Ticker()

Constructor - the internal time point is set to the time point of the construction.

void tick(int add_entry = 1)

void tick(const string &s)

Update the internal time point.

Parameters

add_entry – If not false, leave a record whose duration is the time elapsed since the last updating of internal time point.

The second overload is equivalent to set add_entry = 1 and leave an additional information s for the record.

double duration(int update = 1)

Return the time elapsed in seconds since the last update of the internal clock.

Parameters

update – if true, update the internal clock.

const point_t &last_time_point() const

static point_t now()

last_time_point() : get the last-updated time point of the internal clock.

now() : get the time point of now.

record_t &query(index_t index)

record_t &query_last()

vector<record_t> &query_all() noexcept

const record_t &query(index_t index) const

const record_t &query_last() const

const vector<record_t> &query_all() const noexcept

Visit the recorded event.

• query(index) - query event with given index.

• query_last() - query the last event.

• query_all() - get all records.

query() and query_last() throw on illegal access.

summary_t summary() const noexcept

Return a printable summary instance for statistics.

Usage is like:

Ticker tk;
cout << tk.summary() << endl;

ostream &info(ostream &os = cout, int fmt_cntl = 1) const

friend ostream &operator<<(ostream &os, const Ticker &ticker)

Print the ticker.

Parameters

fmt_cntl – 0 for a small, inline information and otherwise for a more detailed information of all records and their summary statistics.

operator<<() is equivalent to info() with the default fmt_cntl.

Example:

The following codes define a Ticker instance, use it to record events, and print the summary statistics:

Ticker tk;

for(int i=0; i<8; ++i){
    tk.tick(0);
    // Perform some time-consuming computation, e.g.,
    sleep(1);
    tk.tick(str("Task ", i));
}

cout << tk.summary() << endl;

Output:

8 records, duration 1.00041 +/- 2.94286e-08

If more detailed information is needed, directly print the ticker:

cout << tk;

Output:

Ticker instance [loc=0x7ffcb94d97f0, size=32, align=8]
----------
8 records, duration 1.00041 +/- 2.94286e-08
   0:  1.00042, Task 0
   1:  1.00038, Task 1
   2:  1.00057, Task 2
   3:  1.00033, Task 3
   4:  1.00036, Task 4
   5:  1.00077, Task 5
   6:  1.00017, Task 6
   7:  1.00028, Task 7