setTimeout causing full cpu usage with non-integer durations

[sammyt]

I have observed node locking up with full cpu utilization when using setTimeout with non-integer values

The follwing code snipit reliably reproduces the issue on my mac running node version v0.10.30
The t value was generated using Math.random() * 1000 and any such value has the same effect for me

var t = 33.707402646541595
function noop(){}
setInterval(noop, t)
// hangs after a few seconds

The following code however has no problems

var t = 33
function noop(){}
setInterval(noop, t)
// never hangs

I attached a debugger and the runtime appear to be stuck in a tight loop, here inside timers.js

UPDATE: fixed the working code (copy-paste fail)

[loyd]

Confirm overhead. Likely, (1) v8 is forced to use double instead int or (2) conversion double->int occurs at the junction of native and js.

In any case, DOM-version of timers discard fractional part. I think, node's version must do so too.

[misterdjules]

@sammyt Thank you for reporting this issue, I'm looking into this right now.

[misterdjules]

@sammyt @loyd I posted the result of our investigation here: #8067. Stay tuned for more info, hopefully sooner than later.

[hunterloftis]

@misterdjules thanks for looking into it; just got our first support ticket regarding this + 0.10.30 at Heroku.