Gathering JavaScript memory profile data from users

Question

I'm writing a client-heavy site. Since my own testing will only get me so far, I'd like to gather some statistics on how it's performing in the wild.

I'm imagining adding some sort of profiling code to my app which will run some percentage of the time (so it doesn't slow everyone down) and sending that info home.

Adding some timing benchmarks should be easy, but what really becomes a problem with long-running pages with lots of JS is memory usage. Is there a way to instrument the memory used by my app from normal, unprivileged JS code in any of the major browsers? Are there any other good profiling metrics that are available?

Answer 1

In Chrome:

for (var key in performance.memory) {
    alert(key+': '+performance.memory[key]);
}

DEMO: http://jsfiddle.net/usuXV/1/

Sample output:

jsHeapSizeLimit: 1620000000
usedJSHeapSize: 10000000
totalJSHeapSize: 16100000

You can also use console.memory. Seems to return the same results.