High CPU usage since 2.0.6

[Kelden]

I have a lot of tabs and FF is already a bit slow. But since 2.0.6 (or 2.0.7, I don't know. Last version I used was 2.0.5.1), FF isn't usable anymore.
I went back to 2.0.5.1.
E.g. startuptime until FF has loaded all tabs with 2.0.5.1 is 1:30 min.
with. 2.0.7 it's 2:08 min.
And why FF normally uses only 1 to 2 % cpu while I don't use it, it needs now over 25% after some minutes.
How can I help to figure out why it's so slow now?

Kelden

[Giorgio Maone]

How many tabs?
I've got 77 right now opened, and CPU usage is near to 0.

Does this happen on a clean profile with just NoScript installed?
If it doesn't, could you try Standard Diagnostic, in case it's a conflict between NoScript and a different extension?

[Kelden]

600 tabs atm.
I have noscript running on a clean profile on two computers.
I cannot reproduce it there but i only have 20 tabs open.
I can test it with 600 tabs later.

[Kelden]

It happens also with a new profile. Only noscript running and it's much slower with 2.0.7 than 2.0.5.1.

[Giorgio Maone]

It happens also with a new profile. Only noscript running and it's much slower with 2.0.7 than 2.0.5.1.

Just a guess: are you using NoScript Options|Embeddings|Apply these restrictions to whitelisted sites as well?
If so, could you please try to set the noscript.liveConnectInterception about:config preference to false?

[Kelden]

Yes, you are right. I will try your suggestion.

[Kelden]

Now it's fast again after switching the preference to false.
Can you explain what it does? I couldn't find any information for it.

[Giorgio Maone]

Now it's fast again after switching the preference to false.
Can you explain what it does? I couldn't find any information for it.

Here's the reason for this feature.
Please turn it back on after installing latest development build, which implements it in a much faster way, without any noticeable overhead.

[Kelden]

It's much faster then 2.0.7. But still a bit slower (5-10%) than without this option.

[Giorgio Maone]

It's much faster then 2.0.7. But still a bit slower (5-10%) than without this option.

5-10% is too much.
How are you measuring that, exactly?
What kind of CPU have you got?
On a 2.6 Ghz Intel CPU (how many cores is irrelevant, since we're measuring a single thread), I'm measuring an overhead of 1ms at most per page, so you should see a delay of 1 second only if you open 1000 tabs or more.

[Kelden]

I set the option to true, close FF and start it again. I look at the cpu usage in task manager until no more cpu is used.
startup with 310 tabs is 1:33 and with the option set to true it's about 1:45. i have done it 3 times now. i will reboot and test it again

[Kelden]

I have rebooted and done some more testes with 311 Tabs

Slow:
1. 1:42
2. 1:42
3. 1:43
4. 1:41

Fast:
1. 1:41
2. 1:41
3. 1:42


So there is no difference anymore. I haven't tried it with 600 tabs but it looks good.
Thx.