Programmatically get memory usage in Chrome

Question

How can I programmatically get memory usage (JS and total) of my website in Google Chrome?

I looked at doing it from a Chrome extension using the undocumented HeapProfiler (see here), but I can't find a way to get data from that.

I want to measure the memory consumption it at every release, so this needs to be programmatic.

EDIT: I figured out how to get the HeapProfiler method to work. Each addHeapSnapshotChunk event has a chunk of a JSON object.

chrome.browserAction.onClicked.addListener(function(tab) {
  var heapData,
    debugId = {tabId:tab.id};
  chrome.debugger.attach(debugId, '1.0', function() {    
    chrome.debugger.sendCommand(debugId, 'Debugger.enable', {}, function() {
      function headerListener(source, name, data) {
        if(source.tabId == tab.id && name == 'HeapProfiler.addProfileHeader') {
          function chunkListener(source, name, data) {
            if(name == 'HeapProfiler.addHeapSnapshotChunk') {
              heapData += data.chunk;
            } else if(name == 'HeapProfiler.finishHeapSnapshot') {
              chrome.debugger.onEvent.removeListener(chunkListener);
              chrome.debugger.detach(debugId);
              //do something with data
              console.log('Collected ' + heapData.length + ' bytes of JSON data');
            }
          }
          chrome.debugger.onEvent.addListener(chunkListener);
          chrome.debugger.sendCommand(debugId, 'HeapProfiler.getHeapSnapshot', {uid:data.header.uid, type:data.header.typeId});
        }
        chrome.debugger.onEvent.removeListener(headerListener);
      }
      chrome.debugger.onEvent.addListener(headerListener);
      chrome.debugger.sendCommand(debugId, 'HeapProfiler.takeHeapSnapshot');
    });
  });
});

When parsed, the JSON has nodes, edges, and descriptive metadata about the node and edge types and fields.

Alternatively, I could use Timeline events if I just want totals.

That said, are there any better ways than what I've found out here?

Merla

I'm not sure how much details do you require, but have you checked the window.performance object? It gives a brief overview of memory usage and doesn't require extension to be accessed. – Wen

I have, specifically window.performance.memory. It doesn't seem to match the heap profile, though. I actually don't need a lot of details; the total memory usage would be sufficient. – Merla

Answer 1

For anyone that finds this in the future, since version 20 Chrome supports window.performance.memory, which returns something like:

{
  totalJSHeapSize: 21700000,
  usedJSHeapSize: 13400000,
  jsHeapSizeLimit: 1620000000
}

Conchoidal

I've been trying this out, and the values don't change for me, even before and after creating a 1,000,000+ keys/values object... – Boarer

try to start Chrome with CLI flag –-enable-precise-memory-info. – Koontz

@Pavel Vlasov correct version: --enable-precise-memory-info – Laddy

Ok, this does work, but you must make sure no chrome.exe process was running before. – Laddy

in typescript, you may not find window.performance.memory. use (window.performance as any).memory. – Marshy

Answer 2

An alternative approach: write a web page scraper pointing to this URL:

chrome://system/

(note: in case this URL changes again, this is the 'master' URL that lists all the chrome diagnostic pages: chrome://chrome-urls/

the page has a section 'mem_usage' that gives details of memory usage.

maybe there is some way to script Chrome as a user (say in AutoIT or Python?) that loads this URL in Chrome, and then presses the Update button, and then parses the JSON to get the memory usage for whatever tabs you are interested in.

---

OTHER approaches:

• from JavaScript - use window.performance

• from JavaScript - use browser-report.js -

https://www.npmjs.com/package/browser-report

Cohesive

Answer 3

The chrome dev channel has a process api, chrome.process. You can query it for a tab's process information, which includes all kinds of memory information. http://developer.chrome.com/extensions/processes.html

Ancell

Is there a way to call this API from outside of the browser? – Twopence

Answer 4

There is a js library for that: https://github.com/spite/memory-stats.js

Fink

Answer 5

Just an update on this thread: Starting chrome 83, performance.measureMemory() seems to be most reliable way to get memory information on chrome. It gives us the exact memory information even if the same heap is shared by multiple web pages!!. You can find more info at: https://web.dev/monitor-total-page-memory-usage/

Stalker

Renamed to performance.measureUserAgentSpecificMemory starting with Chrome 89. This feature may not always be enabled by default, see the post's link. – Cassowary