问题
On Firefox 66 on Windows 10, I see the performance analysis tool in the Network tab of the Developer Tools.
I click the stop watch icon to start performance analysis for the requests.
But I see the pie charts greyed out and in the loading state always, no matter how long I wait.
Why aren't they showing the performance metrics? Do I have to turn some setting on?
回答1:
You need to refresh the Firefox.
From Reset Firefox preferences to troubleshoot and fix problems
Resetting preferences (zoom, tabs, privacy, network, encryption, updates, where to save file downloads, etc.) is one of many procedures that can be helpful.
You can refresh Firefox using following steps (as of v66.x):
- Open up Firefox
- Head to
about:support - Click on
Refresh Firefox ...button (Firefox will close to refresh itself)
Note: (from mentioned article)
When using the refresh feature, your bookmarks, browsing history, open tabs, windows, passwords, cookies and web form auto-fill information will be saved. However, your extensions and themes will be removed and your preferences will be reset.
回答2:
I can reproduce this problem on a fresh Firefox 66 profile. Searching in the bug tracker brought me to bug 1430698.
According to the info there, Setting network.http.rcwn.enabled to false via about:config solves the problem, and it did work for me. Having said that, it is unclear to me what this option actually does, so use it at your own risk.
来源：https://stackoverflow.com/questions/55663238/firefox-performance-analysis-tool-showing-two-greyed-out-circles-in-loading-stat