[charts] Slow Sparkline on /material-ui/getting-started/templates/dashboard/

[oliviertassinari]

Steps to reproduce

Steps:

1. Open https://mui.com/material-ui/getting-started/templates/dashboard/
2. Use the sorting feature, or pagination feature
3. See how the INP is "poor":

4. See how I'm not the only one: https://pagespeed.web.dev/analysis/https-mui-com-material-ui-getting-started-templates-dashboard/56m6qhi0mo?form_factor=desktop

Context

In my view, this is super important, a demo that doesn't pass webvitals is a demo that doesn't exist. I mean, it's not usable in production.

At 100ms, this starts to be great, e.g. https://dashboard.tremor.so/details

Root cause

The root of the issue seems to be with this column:

I can measure that 90% of the time is spent rendering this.

The root cause might be #9799. Now, it's really weird, I can reproduce this https://stackoverflow.com/questions/52991688/significantly-higher-performance-in-react-whilst-profiling-with-chrome

When I enable profiling mode, it's so much faster 😆, so no longer a true issue.

So maybe the INP reported by https://pagespeed.web.dev/ is actually the theme toggle: