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0 pointsnh21mo ago0 comments

I tried Zed last month but found that it uses high CPU usage even when idle (up to 50% of 1 core of my i7-7500U).

This is even higher CPU usage than my vscode causes.

Sublime does not do that; in fact it has 0% CPU usage when idle:

    sudo strace -fyp "$(pidof sublime_text)"

shows that Sublime issues no syscalls when idle, as it should be.

(Note, you need to either unfocus it so that the caret stops flashing, or switch from fading caret to fixed / non-fading caret, otherwise it necessarily has to do syscalls to draw itself.)

Zed spams syscalls even when its screen is entirely still:

    strace -fyp "$(pidof zed-editor)"

In fact Zed makes 800 syscalls per second when completely idle and unfocused.

0 comments

7 comments · 4 top-level

conartist61mo ago· 2 in thread

From what I recall they generally avoid caching anything and just try to repaint the whole UI really, really fast on every frame so I think that's the design.

It's like how a video game renders, which is their stated goal from the beginning.

I always thought their stated design goals were a bit... wonky.

lstodd1mo ago

If you look into strace of something like IMGUI demo on say sdl2+opengl backend, you'll see about same syscall/sec number at 60 fps, but it'll all be sequences of writev, recvmsg, poll, clock_gettime and DRM_IOCTL_SYNCOBJ_ ioctls. Which is basically just polling for input and submitting gpu command buffers, nothing expensive, and nothing a cache can help with.

nh2OP1mo ago

That does not really matter though: Even immediate-mode approach programs should just not be drawing new frames when the program logic says that there are no new inputs that can result in different pixels (e.g. no user inputs, animations, notifications, text content changes, etc.). One does not need to "poll" for input.

2 more replies

chromadon1mo ago· 1 in thread

I've found that some of the language servers can really grind up a storm but Zed itself is usually pretty lightweight.

nh2OP1mo ago

Can you repro my finding?

I'm running on a Zed with only 1 empty text file in it. So language servers should not be in use.

How do you measure "pretty lightweight"?

nh2OP1mo ago

Syscall spamming is one of the main reasons why computers get slow when many apps are running.

Good software does not do that; when idle, it should only consume RAM, not CPU.

Aside: Browsers, and Electron, seem to always syscall-spam no matter what, which is probably a key reason why people feel that all Electron apps bog down their computers. When your computer gets faster, the software just does more syscall loops per second, for unchanged misery.

frio1mo ago

I've always thought of it as lightweight, but checking it now, wow.

j / k navigate · click thread line to collapse

0 comments

7 comments · 4 top-level

conartist61mo ago· 2 in thread

From what I recall they generally avoid caching anything and just try to repaint the whole UI really, really fast on every frame so I think that's the design.

It's like how a video game renders, which is their stated goal from the beginning.

I always thought their stated design goals were a bit... wonky.

lstodd1mo ago

nh2OP1mo ago

2 more replies

chromadon1mo ago· 1 in thread

I've found that some of the language servers can really grind up a storm but Zed itself is usually pretty lightweight.

nh2OP1mo ago

Can you repro my finding?

I'm running on a Zed with only 1 empty text file in it. So language servers should not be in use.

How do you measure "pretty lightweight"?

nh2OP1mo ago

Syscall spamming is one of the main reasons why computers get slow when many apps are running.

Good software does not do that; when idle, it should only consume RAM, not CPU.

frio1mo ago

I've always thought of it as lightweight, but checking it now, wow.

j / k navigate · click thread line to collapse