Modernize timing functions with C++11 std::chrono

[lemenkov]

Replace legacy POSIX timing APIs with modern C++11 equivalents.

[orgads]

What's the point of removing update_clock_tick?

[lemenkov]

What's the point of removing update_clock_tick?

I believe the original commit (1f5c3ba) made sense at the time - separating the side effect of updating clock_tick from getmilliseconds(), making the intent explicit. However, update_clock_tick() ended up as just oneliner that only assigns a value. This doesn't add much benefit, and made the code just as readable as clock_tick = getmilliseconds().

That said, this is a minor style preference - I am not going to insist on it and happy to revert that particulat part of this PR.

[wdoekes]

Comments are wrong now:

// Returns the number of microseconds that have passed since SIPp
// started. Also updates the current clock_tick.

and

// Returns the number of milliseconds that have passed since SIPp
// started. Also updates the current clock_tick.

[edit] p.s. I prefer update_clock_tick() over clock_tick = getmilliseconds(); -- add inline (moved to header) if you're worried about performance.

[lemenkov]

Comments are wrong now:

// Returns the number of microseconds that have passed since SIPp
// started. Also updates the current clock_tick.

and

// Returns the number of milliseconds that have passed since SIPp
// started. Also updates the current clock_tick.

[edit] p.s. I prefer update_clock_tick() over clock_tick = getmilliseconds(); -- add inline (moved to header) if you're worried about performance.

I'm on it.

[lemenkov]

Comments are wrong now:

// Returns the number of microseconds that have passed since SIPp
// started. Also updates the current clock_tick.

and

// Returns the number of milliseconds that have passed since SIPp
// started. Also updates the current clock_tick.

[edit] p.s. I prefer update_clock_tick() over clock_tick = getmilliseconds(); -- add inline (moved to header) if you're worried about performance.

They were wrong even before. I updated these comments in a separate commit before others.