Time.every relies on javascript's setInterval. Do you see the same drift in Safari/node using setInterval?
If you need more accurate timing, it's possible to attempt that now using a combination of Time.now and Process.sleep (every time you get a message, check the timestamp and calculate how long you want to sleep for). Process.sleep relies on setTimeout, so this can still drift on any given sleep, but you'd be able to calculate a correction when you trigger the next sleep. Also note that it's better if possible to change your logic to not rely on fixed-interval messages, since Javascript itself does not provide a method of real-time scheduling. Instead it's recommended to use the Time value in the message to determine how much you need to update. (This also would let you swap in AnimationFrame.times if you want more responsive updates, which is also recommended over using Time.every with a very small interval.) On Sun, Jun 4, 2017 at 10:17 AM, RGBboy <l-...@rgbboy.com> wrote: > I have been using Time.every for a project that requires ticks at a > constant interval. I found that different platforms drift by varying > amounts. Some platforms seem to oscillate around the desired 0 millisecond > drift. This is acceptable for my use case. However some platforms > constantly increase in drift over time. This is unacceptable for my use > case. > > I put together an example application with Ellie that exhibits the issue ( > https://ellie-app.com/3p4mpnVyTj8a1/2). If you compile and open up the > console you can see how much the application drifts over time in your > browser. I have a bunch of results from the platforms that I have access > to. You can see that Safari and Node.js both increase in drift over time: > > *Chrome 58.0.3029.110:* > > DRIFT: Nothing > DRIFT: Just 4 > DRIFT: Just 4 > DRIFT: Just -1 > DRIFT: Just 0 > DRIFT: Just 1 > DRIFT: Just 2 > DRIFT: Just 3 > DRIFT: Just 5 > DRIFT: Just 1 > DRIFT: Just 3 > DRIFT: Just 4 > DRIFT: Just -1 > DRIFT: Just 1 > DRIFT: Just 0 > DRIFT: Just 2 > > > *Firefox 47.0:* > > DRIFT: Nothing > DRIFT: Just -2 > DRIFT: Just 0 > DRIFT: Just 2 > DRIFT: Just -2 > DRIFT: Just -3 > DRIFT: Just -1 > DRIFT: Just 0 > DRIFT: Just -2 > DRIFT: Just -3 > DRIFT: Just 3 > DRIFT: Just -2 > DRIFT: Just -3 > DRIFT: Just -2 > DRIFT: Just -1 > DRIFT: Just -2 > > > *Safari 10.1:* > > DRIFT: Nothing > DRIFT: Just 0 > DRIFT: Just 0 > DRIFT: Just 4 > DRIFT: Just 3 > DRIFT: Just 4 > DRIFT: Just 4 > DRIFT: Just 4 > DRIFT: Just 5 > DRIFT: Just 5 > DRIFT: Just 6 > DRIFT: Just 7 > DRIFT: Just 8 > DRIFT: Just 9 > DRIFT: Just 10 > DRIFT: Just 11 > > > *Node.js 7.10.0:* > > DRIFT: Nothing > DRIFT: Just 2 > DRIFT: Just 5 > DRIFT: Just 6 > DRIFT: Just 10 > DRIFT: Just 17 > DRIFT: Just 22 > DRIFT: Just 27 > DRIFT: Just 32 > DRIFT: Just 37 > DRIFT: Just 40 > DRIFT: Just 43 > DRIFT: Just 45 > DRIFT: Just 51 > DRIFT: Just 54 > DRIFT: Just 56 > > > *Node.js 8.0.0:* > > DRIFT: Nothing > DRIFT: Just 4 > DRIFT: Just 6 > DRIFT: Just 7 > DRIFT: Just 8 > DRIFT: Just 12 > DRIFT: Just 14 > DRIFT: Just 14 > DRIFT: Just 14 > DRIFT: Just 20 > DRIFT: Just 23 > DRIFT: Just 25 > DRIFT: Just 25 > DRIFT: Just 30 > DRIFT: Just 32 > DRIFT: Just 37 > > > There are a number of ways I can mitigate the issue but I am wondering > where is the most pragmatic place for this to be fixed? > > *The given platform?* > > This would mean Safari, Node and any other inconsistent platforms fix > this. This seems like it is extremely unlikely to happen. For example this > is a known issue across multiple node version that was raised almost a year > ago with no fix yet (https://github.com/nodejs/node/issues/7346). > > *Elm's Core Time module?* > > This would give consistent behaviour for all consumers no matter what > platform they are running on. I have made a proof of concept that enables > this so it is possible. I'm just not sure if this is a change that aligns > with the intension of the module. > > *My application?* > > There are a number of things I could do within my application to mitigate > the issue (which I am already doing). For example I could track the drift > and counter it in my subscription. My only reservation here is that others > will face the same issue. > > -- > You received this message because you are subscribed to the Google Groups > "Elm Discuss" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to elm-discuss+unsubscr...@googlegroups.com. > For more options, visit https://groups.google.com/d/optout. > -- You received this message because you are subscribed to the Google Groups "Elm Discuss" group. To unsubscribe from this group and stop receiving emails from it, send an email to elm-discuss+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
