But I’ve been using it for a while and I don’t notice that most of the web is significantly slower. I can notice some performance hits, but I use slow machines to start with - my gutless wonder ARM boxes and such.
If you want to try it, with Firefox, go into about:config and change the following to false:
Chromium based browsers seem to require the command line flag --js-flags="--jitless" - though there may be a flag as well. I don’t have one handy.
And I’ve no idea how to do it on desktop Safari, though on mobile iOS 16 Safari, Lockdown Mode disables jit.
Would people be willing to try this for a couple days in “general use,” and report back? I’m thinking of doing a blag post on the matter, and I’d prefer a few more regular users than me with the impressions of it.
Slightly of topic: I’ve been using lockdown mode on mobile for nearly a month. I’ve not done a side by side comparison to verify some of these aren’t just broken websites, but so far I’ve noticed:
Missing icons (reduced font support)
An article endlessly repeating the last couple sections on one of the tech [sites]
Navigation menus not going where they should
Text moving around on me when scrolling
The first is the only one [I’m] certain is a lockdown artifact. The last two I see sometimes because websites are broken, but I’ve noticed it more lately.
None felt like performance being slow. None convinced me to disable lockdown.
About Lockdown Mode - Apple Support says Lockdown Mode works on macOS Ventura, but I don’t know how to tell if it changes JIT settings. I suppose a benchmark site could tell me - anyone have one? I’ve Ventura and can test.
It would be nice to 'ave JIT disabled by default and then you could selectively turn it on on sites you really need it for, if any exist.
At least on iOS, this is how Lockdown mode works. It disables all the stuff, but you can go to the settings for a specific site (domain) and disable Lockdown - you get everything back, not just JIT, so webfonts, WebGL, etc. But it’s a per-domain toggle.
I don’t have anything that will run Ventura. My most recent, and likely to be last ever, is a 2015 MacBook Pro. Nice machine, figured it would be the last given the 2016+ keyboards, then Apple went and went nuts, and put out a nice laptop, but anymore I have no reason to have a recent Mac, and I don’t really trust them. The iPhone 2020 SE is… tolerable, barely, but I moved away from Apple hardware and don’t see a reason to move back.
I didn’t notice it such that I forgot it was still on, but to be fair that wasn’t my main laptop.
For normal people I suspect they’d be just fine enabling it, and I wouldn’t be surprised if this eventually becomes one of those “default off, ask if it should be on per site” like the camera and the microphone are now.