650709 - Suspiciously high performance impact reported for Personas Plus and SimilarWeb on Windows 7

Status: RESOLVED FIXED

(Testing :: Talos, defect, P2)

Description

[Jorge Villalobos [:jorgev] (he/him)]

If you look at the results of the last run, on Windows 7 both Personas Plus and SimilarWeb have extremely high impact percentages (201% and 221%, respectively). At least in the case of Personas Plus this is making the add-on appear on the top slowness list when it probably shouldn't be there (although it comes close anyway).

We should investigate the cause of these discrepancies, and discard the Windows 7 results for both these add-ons, or all of them if we discover this is a more general problem.

Comment 1

[Wladimir Palant]

Personas Plus slowdown appears to be real - I also get 2 seconds additional delay on my Windows 7 machine. Reason seems to be the Groovy Blue persona that is selected by default. If I change extensions.personas.selected pref default in the extension package from "current" to "default" (use the regular Firefox 4 theme) I get only 70 ms delay. Why the same slowdown doesn't appear on other platforms is a good question.

Comment 2

[Wladimir Palant]

The delay caused by SimilarWeb is also real, more than 2 seconds for me (very noticeable even without about:startup). This element in chrome://similarweb/content/toolbar.xul (a browser overlay) is responsible:

<toolbaritem id="googleAnalytics">
 	<iframe type="content" src="http://analytics.similarweb.com/similarweb_ff.html?type=2" height="0" width="0" collapsed="true"/>
</toolbaritem>

Why the same frame supposedly doesn't cause delays on platforms other than Windows 7 is beyond me.

Comment 3

[Wladimir Palant]

Please note that in case of Personas Plus selecting that ugly persona is really sufficient - after that you can disable the extension, the code built into Firefox will take over and still cause exactly the same slowdown.

Comment 4

[Jorge Villalobos [:jorgev] (he/him)]

My understanding is that Talos boxes run with all hosts redirected to localhost, so network latency doesn't factor in the tests. The delays shouldn't happen unless the Windows 7 tests are being run with a different setup.

I'll look into the issues you mentioned and contact the authors. Thank you for investigating this.

Comment 5

[Wladimir Palant]

(In reply to comment #4)
> My understanding is that Talos boxes run with all hosts redirected to
> localhost, so network latency doesn't factor in the tests.

I'm not entirely sure about that. It does run with localhost:80 as proxy but if I see it correctly then there isn't anything on that port. So you might be measuring proxy connection timeout there. Not that a content frame should delay the browser window in the first place...

Comment 6

[(not currently active) Ted Mielczarek]

This reminds me of bug 617503. I don't have anything but suspicion there, though.

Comment 7

[alice nodelman [:alice] [:anode]]

From comment #1 and comment #2 it appears that these are real regressions - can we close this bug as it is filed against talos?

Comment 8

[Jorge Villalobos [:jorgev] (he/him)]

Alice, can you shed some light on comment #5?

Comment 9

[alice nodelman [:alice] [:anode]]

Talos runs the browser proxied to localhost.  Every talos slave has a local apache server - there should be no proxy timeouts affecting numbers.

Comment 10

[Wladimir Palant]

(In reply to comment #6)
> This reminds me of bug 617503. I don't have anything but suspicion there,
> though.

It seems at least not unrelated. Changing the proxy from "localhost" to "127.0.0.1" results in 1 second slowdown instead of 2 seconds. Removing the proxy setting altogether results in again 0.5 seconds less delay. This is independent of whether I have a web server on port 80.

Comment 11

[Wladimir Palant]

(In reply to comment #10)
> This is independent of whether I have a web server on port 80.

Sorry, that statement was wrong. I tried the fix from bug 617503, added this preference to the config file:

>  network.dns.ipv4OnlyDomains: localhost

This works. If in addition I have a web server on port 80 then I get the expected slowdown for SimilarWeb (200 ms).

Comment 12

[Wladimir Palant]

Personas Plus is the same issue. Adding that pref reduces the slowdown to 100ms.

Comment 13

[alice nodelman [:alice] [:anode]]

Would we like to have that pref added to the addon.config file?

Comment 14

[Jorge Villalobos [:jorgev] (he/him)]

I think it should be added, yes, given that its default value doesn't provide any benefits.

Comment 15

[alice nodelman [:alice] [:anode]]

Attachment: [checked in]add "network.dns.ipv4OnlyDomains: localhost" to addon.config

Comment 16

[Joel Maher ( :jmaher ) (UTC -8)]

Comment on attachment 529817 [details] [diff] [review]
[checked in]add "network.dns.ipv4OnlyDomains: localhost" to addon.config

Review of attachment 529817 [details] [diff] [review]:

::: addon.config
@@ +54,5 @@
   extensions.firebug.net.enableSites : true 
   extensions.firebug.script.enableSites : true
   extensions.checkCompatibility.4.0 : false
   noscript.default: 'file:// about:blank about:credits addons.mozilla.org mozilla.net flashgot.net google.com gstatic.com googleapis.com securecode.com informaction.com yahoo.com yimg.com yahooapis.com maone.net noscript.net hotmail.com msn.com passport.com passport.net passportimages.com live.com js.wlxrs.com'
+  network.dns.ipv4OnlyDomains: localhost

not to be too picky, but all the other prefs have a space between the pref and the colon.  Just to keep it uniform, we should change this line to:
network.dns.ipv4OnlyDomains : localhost

Since we are not running these remotely, this is fine to assume localhost.

Comment 17

[alice nodelman [:alice] [:anode]]

Comment on attachment 529817 [details] [diff] [review]
[checked in]add "network.dns.ipv4OnlyDomains: localhost" to addon.config

changeset:   236:d9bbd5b5917c

Comment 18

[alice nodelman [:alice] [:anode]]

Deployed patch.

Please re-open is performance results are still not trusted.