1327522 - (e10s-specific) Please allow user to distinguish content processes from parent process in Task Manager in order to kill them

Status: RESOLVED WORKSFORME

(Core :: DOM: Content Processes, enhancement)

Description

[arni2033]

>>>   My Info:   Win7_64, Nightly 49, 32bit, ID 20160526082509
Use case:
I have many tabs (each of them is not important) and want to close the most heavy child processes


>>>
STR_1:
1. Open 10 tabs with http://www.rp-online.de/
2. Open this url in a new tab:   data:text/html,<script>while(1){}</script>
3. Kill the hang process via task manager to at least save work in other processes (see Note 1)

AR:
 Step 3 is often impossible to perfirm. In STR_1 it's clear that hang process consumes ~25% CPU,
 but in more complex cases content process may consume 0% CPU, and just not respond,
 and consume the same amount of RAM as parent process or any other child process.
ER:
 There should be a way to kill content process that consumes undesired amount of resources
 (i.e. literally any content process) and be 100% sure that it's not the parent process.
 Note that use case above assumes I don't care about child processes, but don't want to finish the
 session to save at least some part of progress made in tabs (cached videos, typed messages, etc)

Notes:
1) Sometimes content processes consume normal amount of resources, I just need to kill some of them
  (in some cases it doesn't matter which ones), because total RAM consumption is too high
2) The summary asks for the most obvious way to fix described issue(s), but it's not the only way
3) I know that many people just want to copy all aspects of GoogleChrome behavior w/o thinking through
   GoogleChrome doesn't allow to distinguish child process from content process in Task manager, but:
 3.1) GoogleChrome doesn't have this bug. It allows to safely kill child process
 3.2) There's usually no need to kill child process in GoogleChrome, because it never consumes all RAM
 3.3) The pursuit of bad behavior present on other browsers w/o firs adding a good behavior, also
      present on those browsers is the worst strategy. FF only had a few advantages over some other browsers, and now due to said stategy their number is rapidly decreasing.

Comment 1

[Gabor Krizsanits (INACTIVE)]

If that helps you can open about:performance there you can see the pid of the content processes... But I agree, I wouldn't mind if hovering the mouse over a tab would specify the pid it is currently running in (maybe we could hide this behind a pref so we wouldn't need a UX discussion about it)

Comment 2

[Blake Kaplan (:mrbkap) (inactive)]

As of today, it's possible to hover over a tab to see what PID it is. This is already WFM on OSX and Linux but maybe something can be done for Windows.

Comment 3

[Ciprian Muresan [:cmuresan], Ecosystem QA]

Actually, this is also fixed on Windows too on the latest Nightly (Build ID 	20170202030211). Just did a regression range and got:

First good revision: 3613ce87bd3dcc611c0e24d2fbeb456d56a4fc69
Last bad revision: 59681d9f5e9482011d4547bea9c12f26cd36e101
Pushlog:
https://hg.mozilla.org/integration/mozilla-inbound/pushloghtml?fromchange=59681d9f5e9482011d4547bea9c12f26cd36e101&tochange=3613ce87bd3dcc611c0e24d2fbeb456d56a4fc69

Looks like the following bug has the changes which introduced the fix:
https://bugzilla.mozilla.org/show_bug.cgi?id=1333277

Considering this, I will mark the issue as Resolved-WFM

Comment 4

[Bob]

The hover functionality described as working in comment 2 and comment 3 seems to only apply to Nightly, no? It's not available in release versions.

Comment 5

[Ciprian Muresan [:cmuresan], Ecosystem QA]

@Bob, yes that is correct. The tab PIDs will only show up as tooltips if you are using Nightly.