• Posts
  • RSS
  • ◂◂RSS
  • Contact

  • Overhead of MessageChannel

    March 27th, 2020
    tech  [html]
    The Channel Messaging API gives you a way to pass information asynchronously between different origins on the web, such as cross-origin iframes. Traditionally you would use window.postMessage(), but the a MessageChannel has the advantage of being clearer, only requiring validating origins on setup, and handling delegation better. Reading this 2016 post, however, I was worried that it might have enough overhead that postMessage made more sense in performance-sensitive contexts. Benchmark time!

    I made a test page which alternates between loading trycontra.com/test/messageChannelResponse.html and trycontra.com/test/postMessageResponse.html. I'm using two different domains so that I can test cross-origin performance. First it loads messageChannelResponse in an iframe, waits for it to load, and then times how long it takes to pass in a MessagePort and receive a response on it. Then it does the same basic operation postMessageResponse with plain postMessage. This is a worst-case for MessageChannel, since I stand up the while channel only to use it a single time.

    I ran 1,000 iterations, interleaved, on Chrome (80.0), Firefox (74.0), and Safari (13.1). All of these were on my 2017 MacBook Pro. Here are all the runs, sorted from fastest to slowest [1]:

    In Chrome, MessageChannel is a bit faster, while in Firefox and especially Safari it's slower. Additionally, Firefox runs it faster than Safari, which runs it faster than Chrome. Safari also has more consistent performance than Chrome, with a flatter distribution. Firefox is in between, with a flat distribution for postMessage but a few slow calls in the tail for MessageChannel. If you're writing something where ~7ms/call in Safari is an issue then it might be worth sticking to postMessage, otherwise MessageChannel seems fine.


    [1] I find this kind of "sideways CDF" a really useful visualization tool, and possibly the chart I make most often.

    Comment via: facebook, lesswrong

    Recent posts on blogs I like:

    Economics: not as bad as I thought

    Also, it's not all about money. The post Economics: not as bad as I thought appeared first on Otherwise.

    via Otherwise May 13, 2022

    Buckingham Palace

    I love England. Especially because of the big castle called Buckingham Palace. I got to see the outside there, but my mom showed me some pictures of the inside. I love it there. But the outside doesn't look very fancy to me. But I never knew why those …

    via Anna Wise's Blog Posts April 25, 2022

    What is causality to an evidential decision theorist?

    (Subsumed by: Timeless Decision Theory, EDT=CDT) People sometimes object to evidential decision theory by saying: “It seems like the distinction between correlation and causation is really important to making good decisions in practice. So how can a theor…

    via The sideways view April 17, 2022

    more     (via openring)


  • Posts
  • RSS
  • ◂◂RSS
  • Contact