952754 - Panorama allocates lots of memory and notable strings

Status: RESOLVED WONTFIX

(Firefox Graveyard :: Panorama, defect)

Description

[Arpad Borsos [:Swatinem]]

STR:

1. open about memory
2. GC, CC, minimize memory usage
3. measure -> Some 587M explicit usage.
4. open panorama
5. close panorama
6. measure again -> some 640M explicit usage

Also, panorama allocates tons of json strings, like this one:
```
│  │  │   │      ├──2.00 MB (00.31%) ++ string(length=702263, copies=2, "{"windows":[{"tabs":[{"entries":[{"url":"about:memory","ID":191665935,"docshellID":6,"owner_b64":"CbflmEkNQj+opi5sTsh3UAAAAAAAAAAAwAAAAAAAAEYB3pRy0IA0EdOTmQAQS6D9QDlf4EV9GErbo/2vmMihrxEAAAAD//////////8BAAAAKGZpbGU6Ly8vaG9tZS9zd2F0aW5lbS9Db2RpbmcvaW5mZXJlbmNlcy8AAAAAAAAABAAAAAcAAAAAAAAAAP////8AAAAA/////wAAAAD/////AAAABwAAACEAAAAHAAAAIQAAAAcAAAAhAAAAKAAAAAAAAAAo/////wAAAAD/////AAAAB/////8AAAAH/////wEAAAAAAAEAAAABAAAAAAAA","docIdentifier":53,"scroll":"0,0"}],"lastAccessed":1387627630312,"pinned":true,"hidden":false,"attributes":{},"image":null,"extData":{"weaveLastUsed":"1387629314"},"index":1},{"entries":[{"url":"" (truncated))
│  │  │   │      ├──0.38 MB (00.06%) ++ string(length=97667, copies=2, "{"entries":[{"url":"https://www.google.com/search?q=" (truncated))
│  │  │   │      ├──0.34 MB (00.05%) ++ string(length=88753, copies=2, "{"entries":[{"url":"https://www.google.com/search?q=" (truncated))
│  │  │   │      ├──0.34 MB (00.05%) ++ string(length=89452, copies=2, "{"entries":[{"url":"https://www.google.com/search?q=" (truncated))
│  │  │   │      ├──0.34 MB (00.05%) ++ string(length=87533, copies=2, "{"entries":[{"url":"https://www.google.com/search?q=" (truncated))
```

This json sometimes contains a `storage` key, that can include arbitrary data, such as css or whatnot. (is it the localstorage of the site?)

Panorama just should not allocate 50M of temporary data (which is cleared on GC and leads to memory fragmentation) which also includes tons of probably useless json structures.

Comment 1

[Arpad Borsos [:Swatinem]]

Ok, so there is 40M overhead of about:memory itself in there, haha.

So instead of "measure" one has to do "measure and save" which avoids that.

"load and diff" then shows 11M memory usage, 5.5M of which is those newly created notable strings.

Comment 2

[Justin Dolske [:Dolske]]

Panorama has been removed from Firefox 45, currently in Beta and scheduled for release on March 7th. As such, I'm closing all existing Panorama bugs.

If you are still using Panorama, you will see a deprecation message in Firefox 44, and when 45 is released your tab group data will be migrated to bookmarks, with a folder for each group. There are also a few addons offering similar functionality.

See https://support.mozilla.org/en-US/kb/tab-groups-removal for more info.

We're removing Panorama because it has extremely low usage (about 0.01% of users), and has a large number of bugs and usability issues. The cost of fixing all those issues is far too high to justify, and so we'll instead be focusing our time and energy on improving other parts of Firefox.