This is a continuation of my Are They Slim Yet series. For background see my previous installment.

Firefox’s upcoming release 57 has a huge focus on performance. We’ve quantum-ed all the things but we haven’t really talked about memory usage, which is something that often falls by the wayside in the pursuit of performance. Luckily since we brought AWSY in tree it’s been pretty easy to track memory usage and regressions even on separate development branches. The Stylo team was a big user of this and it shows, we flipped the switch to enable Stylo by default around the 7th and you can see a fairly large regression, but by the 16th it was mostly gone:

Some great work has been happening lately to reduce Stylo's memory usage. https://t.co/TkwPKOQRT2 and https://t.co/C8x59Ur5IC have details. — Nicholas Nethercote (@nnethercote) September 15, 2017

Hopefully I’ve convinced you we’ve put a lot of work into performance, now let’s see how we’re doing memory-wise compared to other browsers.

The methodology for the test is the same as previous runs: I used the ATSY project to load 30 pages and measure memory usage of the various processes that each browser spawns during that time.

The results

Edge has the highest memory usage on Windows, Chrome comes in with 1.4X the memory usage of Firefox 64-bit on Windows, about 2X Firefox on Linux. On macOS Safari is now by far the worst offender in memory usage, Chrome and Firefox are about even with Firefox memory usage having gone up a fair amount since the last time I measured.

Overall I’m pretty happy with where we’re at, but now that our big performance push is over I’d like to see us focus more on dropping memory usage so we can start pushing up the number of content processes. I’d also like to take a closer look into what’s going on on macOS as that’s been our biggest regression.

Browsers included are Edge 38 on Windows 10, Chrome Beta 62 on all platforms, Firefox Beta 57 on all platforms, and Safari Technology Preview 40 on macOS 10.12.6.

Note: I had to run the test for Safari manually again, they seem to have made some changes that cause all of the pages from my test to be loaded in the same content process.