2-4% Linux*/Win* sessionrestore regression on Fx-Team on May 25, 2015 from push 08dfcb03f55b

RESOLVED FIXED in Firefox 41

Status

()

defect
RESOLVED FIXED
4 years ago
2 years ago

People

(Reporter: jmaher, Assigned: jryans)

Tracking

(Blocks 1 bug, {perf, regression})

unspecified
mozilla41
Points:
---
Dependency tree / graph

Firefox Tracking Flags

(firefox41 fixed)

Details

(Whiteboard: [talos_regression])

Attachments

(1 attachment)

Talos has detected a Firefox performance regression from your commit 08dfcb03f55b in bug 1164448.  We need you to address this regression.

This is a list of all known regressions and improvements related to your bug:
http://alertmanager.allizom.org:8080/alerts.html?rev=08dfcb03f55b&showAll=1

On the page above you can see Talos alert for each affected platform as well as a link to a graph showing the history of scores for this test. There is also a link to a treeherder page showing the Talos jobs in a pushlog format.

To learn more about the regressing test, please see: https://wiki.mozilla.org/Buildbot/Talos/Tests#sessionrestore.2Fsessionrestore_no_auto_restore

Reproducing and debugging the regression:
If you would like to re-run this Talos test on a potential fix, use try with the following syntax:
try: -b o -p linux,win64,win32 -u none -t other  # add "mozharness: --spsProfile" to generate profile data

To run the test locally and do a more in-depth investigation, first set up a local Talos environment:
https://wiki.mozilla.org/Buildbot/Talos/Running#Running_locally_-_Source_Code

Then run the following command from the directory where you set up Talos:
talos --develop -e <path>/firefox -a sessionrestore

Making a decision:
As the patch author we need your feedback to help us handle this regression.
*** Please let us know your plans by Monday, or the offending patch will be backed out! ***

Our wiki page oulines the common responses and expectations:
https://wiki.mozilla.org/Buildbot/Talos/RegressionBugsHandling
this is a series of patches on the same push:
http://hg.mozilla.org/integration/fx-team/pushloghtml?fromchange=301df7d05cf4&tochange=08dfcb03f55b

I did a few retriggers and this is showing that the push really is the culprit:
https://treeherder.mozilla.org/#/jobs?repo=fx-team&fromchange=31c58b01300a&tochange=7637b24cd7a5&filter-searchStr=Ubuntu%20HW%2012.04%20x64%20fx-team%20talos%20other

:jryans, can you look into why this is happening?
Flags: needinfo?(jryans)
Assignee

Comment 2

4 years ago
Yes, I'll investigate this.  Let's avoid backing out if at all possible.
Assignee: nobody → jryans
Status: NEW → ASSIGNED
Flags: needinfo?(jryans)
thanks, ask for help as needed!
I suggest seeing if removing the loadFrameScript in browser.js's onload makes it go away. Worth testing with a try push. If so, we might be able to load it lazily when a view source tab is first opened.
Assignee

Comment 5

4 years ago
(In reply to Mike Conley (:mconley) - PTO until June 2nd from comment #4)
> I suggest seeing if removing the loadFrameScript in browser.js's onload
> makes it go away. Worth testing with a try push. If so, we might be able to
> load it lazily when a view source tab is first opened.

Right, that was my first plan of attack. :)
Assignee

Comment 6

4 years ago
Let's see if the frame script is indeed the cause:

https://treeherder.mozilla.org/#/jobs?repo=try&revision=95f816b4992f
Assignee

Comment 7

4 years ago
Joel, the try syntax you suggested in comment 0 appears to have not run Talos at all.  Is there a different syntax I should use?
Flags: needinfo?(jmaher)
I have triggered the jobs via mozci (https://github.com/armenzg/mozilla_ci_tools).  I need to look into the talos syntax for other, I believe it should have been other_nol64, so many quirks and details.

sorry for misleading you!
Flags: needinfo?(jmaher)
looking at the numbers they look better!  I would say this patch fixes the regression.
Assignee

Comment 10

4 years ago
(In reply to Joel Maher (:jmaher) from comment #9)
> looking at the numbers they look better!  I would say this patch fixes the
> regression.

Great!  The current patch on try also removes functionality, so I'll now try to craft a lazy version that keeps the correct functionality without affecting the Talos metric.
Assignee

Comment 12

4 years ago
(In reply to J. Ryan Stinnett [:jryans] (use ni?) from comment #11)
> Testing a potential fix:
> 
> https://treeherder.mozilla.org/#/jobs?repo=try&revision=554cc51520fc

Joel, this try run looks good to me, do you agree?
Flags: needinfo?(jmaher)
yes, these numbers look a LOT better!  thanks:)
Flags: needinfo?(jmaher)
Assignee

Comment 15

4 years ago
Bug 1169723 - Load view source frame script lazily. r=mconley
Attachment #8614767 - Flags: review?(mconley)
Assignee

Comment 17

4 years ago
Comment on attachment 8614767 [details]
MozReview Request: Bug 1169723 - Load view source frame script lazily. r=mconley

Bug 1169723 - Load view source frame script lazily. r=mconley
Comment on attachment 8614767 [details]
MozReview Request: Bug 1169723 - Load view source frame script lazily. r=mconley

https://reviewboard.mozilla.org/r/10035/#review9023

This looks fine to me.

I wonder how much more session restore time we could save by getting rid of more of those loadFrameScript calls. I've filed bug 1171720 to investigate that.

Thanks jryans!
Attachment #8614767 - Flags: review?(mconley) → review+
Assignee

Comment 19

4 years ago
(In reply to Mike Conley (:mconley) - Needinfo me! from comment #18)
> Comment on attachment 8614767 [details]
> MozReview Request: Bug 1169723 - Load view source frame script lazily.
> r=mconley
> 
> https://reviewboard.mozilla.org/r/10035/#review9023
> 
> This looks fine to me.
> 
> I wonder how much more session restore time we could save by getting rid of
> more of those loadFrameScript calls. I've filed bug 1171720 to investigate
> that.
> 
> Thanks jryans!

It even adds a feature: view source tabs restored from session restore did not have working "extra" features like "Go to Line" before this patch.
> +    // If the restored browser wants to show view source content, start up a
> +    // view source browser that will load the required frame script.
> +    if (uri && ViewSourceBrowser.isViewSource(uri)) {
> +      new ViewSourceBrowser(browser);
> +    }

This seems less than ideal, why would sessionstore have to know about this special type of browser? Can we please handle this differently? Sessionstore should not have to know about any tab's content/display and treat it differently.
Flags: needinfo?(jryans)
> +// Keep a set of browsers we've seen before, so we can load our frame script as
> +// needed into any new ones.
> +let gKnownBrowsers = new WeakSet();
>
>   gKnownBrowsers.add(this.browser);

This will break with docShell swapping. If drag&drop a view-source: tab to another window it will load the frame-script there again.
https://hg.mozilla.org/mozilla-central/rev/173a4adce55e
Status: ASSIGNED → RESOLVED
Closed: 4 years ago
Resolution: --- → FIXED
Target Milestone: --- → mozilla41
(In reply to Tim Taubert [:ttaubert] from comment #21)
> > +    // If the restored browser wants to show view source content, start up a
> > +    // view source browser that will load the required frame script.
> > +    if (uri && ViewSourceBrowser.isViewSource(uri)) {
> > +      new ViewSourceBrowser(browser);
> > +    }
> 
> This seems less than ideal, why would sessionstore have to know about this
> special type of browser? Can we please handle this differently? Sessionstore
> should not have to know about any tab's content/display and treat it
> differently.

Heh, I guess when it comes to talos regressions, my tolerance for hacks goes up. :)

Do you feel we should back this out while we look for an alternative solution?
Flags: needinfo?(ttaubert)
I think backing out is a little too drastic, I would like to see a follow-up though to make sure we'll replace that with a better solution soon.
Flags: needinfo?(ttaubert)
Assignee

Comment 27

4 years ago
(In reply to Tim Taubert [:ttaubert] from comment #26)
> I think backing out is a little too drastic, I would like to see a follow-up
> though to make sure we'll replace that with a better solution soon.

Sorry for the trouble!  I do think it's good to keep it in for the Talos improvement, and we can improve the approach in bug 1171986.
Flags: needinfo?(jryans)
Depends on: 1387884
Assignee

Updated

2 years ago
No longer depends on: 1387884
You need to log in before you can comment on or make changes to this bug.