I'm trying to create new theme. But every time I reload the home page it is going to high CPU loading.

My Settings:
New theme has just one file: /app/design/frontend/Test/default/web/css/source/_extend.less
Magento mode: developer
Front-end development workflow: Server-side less compilation
Grunt: installed and configured.

Activity monitor:

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Chrome console:

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And only after php bin/magento setup:static-content:deploy the page is loading fast:

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Do I need to deploy static content every time I change some css style if I develop new theme?

Thanks in advance!

I have asked also in github issue: https://github.com/magento/magento2/issues/2731

Here is similar question: https://github.com/magento/magento2/issues/2924

1 Answer 1


When server side compilation is enabled, the server will compile the less files to CSS after every change. Therefore, the CPU will rise and the frontend will load slow.

It's better to switch to client side compilation when developing a theme. Less compilation will then take place on the client side, which is a lot faster (~1 sec in my experience), eventhough it has to wait for all less files to be loaded.

Also, compiling CSS (server side and/or client side) might be slower when you've created a new less file, as the less file has to be moved to the pub/static directory first.

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