Translation: "You're doing something reasonable. But we don't think you should do it that way, so we're going to shoot you in the foot and then blame you for it." I'm on board with this plan. <- sarcasm
Seriously though. Can we at least hear what other options y'all have considered for fixing the original problem? Is there a test case that reproduces it that we can examine? I don't want to mess with nextTick because it works as designed. But if there's no other solution to the problem, I could get behind introducing setImmediate. But with that it seems we're signing up for a whole new round of educating devs about what to do in order to not miss their data events. Sure it seems easy in theory (change nextTick to setImmediate), but in practice it will create a lot of confusion and ambiguity about what just changed. :Marco PS - Sorry I missed the message about moving discussion to the github ticket :-/ On Tue, May 29, 2012 at 1:45 PM, Isaac Schlueter <[email protected]> wrote: > Computationally expensive stuff should be done in a child process, or > a uv_work_t thread in an addon. nextTick is a bad fit for this. > setTimeout(fn, 0) is not quite as bad, but it is slower. > > We can look into adding a setImmediate function for 0.9 that matches > the semantics of the web browser. The intent of setImmediate is to be > used for cases like this, and it should be pretty easy to implement. > > On Tue, May 29, 2012 at 1:31 PM, Mikeal Rogers <[email protected]> > wrote: > > I have never seen nextTick recommended for breaking up computationally > > expensive tasks, this is what cluster and child_process are for. > > > > Also, setTimeout(cb,0) is very efficient in node and does not suffer the > > penalties we are familiar with from the browser. It's actually a better > fit > > for this use case than nextTick(). > > > > -Mikeal > > > > > > On May 29, 2012, at May 29, 201212:23 PM, Bruno Jouhier wrote: > > > > +1 > > > > nextTick is the efficient way to yield to another "thread of processing" > > (thread between quotes of course) when performing an expensive > computation. > > So it is the antidote to starvation and thus a very useful call. > > > > If you change its behavior, you should at least provide a replacement > call > > which will be at least as efficient (unlike setTimeout(cb, 0)). And then > why > > not keep nextTick as is and introduce another call with a different name > > (like afterTick as someone suggested) if you really need one. > > > > > > On Tuesday, May 29, 2012 2:43:20 AM UTC+2, phidelta wrote: > >> > >> I think that the current semantics have value. I use nextTick when I > >> want to ensure that io can happen between the invocation and the > >> ticked call. As well as to work with a new call stack. > >> > >> For example when I emit an event whose lister also emits an event and > >> so on, I create a potentially long chain of stuff that can happen > >> within a tick. So when I emit from within a listener I usually > >> nextTick the emit to allow io in between. > >> > >> So if you change nextTick to really mean "at the end of this tick", at > >> least we will want a function like reallyNextTick that keeps the > >> current behavior. Of course I would need to do a search replace over a > >> lot of code, but I could live with that. > >> > >> > >> On May 26, 7:50 pm, Isaac Schlueter <[email protected]> wrote: > >> > How would you feel about changing the semantics of process.nextTick > >> > such that the nextTick queue is *always* cleared after every v8 > >> > invocation, guaranteeing that a nextTick occurs before any IO can > >> > happen? > >> > > >> > This would imply that you can starve the event loop by doing nextTick. > >> > So, for example, the timeout would never fire in this code: > >> > > >> > setTimeout(function () { > >> > console.log('timeout')}) > >> > > >> > process.nextTick(function f () { > >> > process.nextTick(f) > >> > > >> > }) > >> > > >> > Reasoning: > >> > > >> > We have some cases in node where we use a nextTick to give the user a > >> > chance to add event handlers before taking some action. However, > >> > because we do not execute nextTick immediately (since that would > >> > starve the event loop) you have very rare situations where IO can > >> > happen in that window. > >> > > >> > Also, the steps that we go through to prevent nextTick starvation, and > >> > yet try to always have nextTick be as fast as possible, results in > >> > unnecessarily convoluted logic. > >> > > >> > This isn't going to change for v0.8, but if no one has a use-case > >> > where it's known to break, we can try it early in v0.9. > > > > > -- Marco Rogers [email protected] | https://twitter.com/polotek Life is ten percent what happens to you and ninety percent how you respond to it. - Lou Holtz
