306570 - High CPU usage when downloading files

Status: RESOLVED DUPLICATE of bug 397424

(Toolkit :: Downloads API, defect)

Description

[Benoît Dejean]

User-Agent:       Mozilla/5.0 (X11; U; Linux ppc; fr; rv:1.7.10) Gecko/20050824 Firefox/1.0.6 (Debian package 1.0.6-3)
Build Identifier: Mozilla/5.0 (X11; U; Linux ppc; fr; rv:1.7.10) Gecko/20050824 Firefox/1.0.6 (Debian package 1.0.6-3)

Firefox eats ~40% of CPU when downloading files. This is 100% noticeable when i
download big files (like linux kernel) at hi-speed (> 1Mb/s). Downloading files
with other tools like wget/curl/gnomevfs-cat doesn't cause such hi CPU usage.

This is very annoying because it means that when i want to download big files, i
need to start the download in a terminal so my CPU can serve more useful tasks.

Reproducible: Always

Comment 1

[Jo Hermans]

see the discussion in bug 270312 (clearing download history helps a lot f.i.)

*** This bug has been marked as a duplicate of 270312 ***

Comment 2

[Benoît Dejean]

i don't get spikes. When i start a download, i get a 40% CPU usage whatever i do
(and even if i don't do anything). I don't think this is the same bug.

Comment 3

[Benoît Dejean]

i get a 40% CPU usage with the download manager closed (i choose not to open it
on new download)

Comment 4

[klonos]

I'm using latest nightlies for 3-4 years now. This bug is far from resolved and it keeps tormenting me. I originally thought that if I gave it enough time it would eventually be solved, but alas!!!...

Yes, it does seem to be caused when you have a quite large download history, so you won't see it happen in a fresh profile if you're going through the standard troubleshooting steps. I guess purging the download history would make the bug go away, but that's no solution (I don't want to delete this history, because I need it). Instead of actually solving this, we're simply "hiding the dust under the carpet".

Let me note here that I have set my download manager pop-up window to never open (I can see the progress from the status bar) + I have disabled addons that would "invoke" it or that would even "take a peak" at my download history (like the Download Status Bar & Download Manager Tweak for example).

Proposed solution: Could we just archive older download history and show only some limited subset of it (based on a time-ago setting or a certain number of latest downloaded files)? We could then "lazy-load" the rest of the download history only upon request. For example when one opens the download history and actually searches for files downloaded a year ago or when they scroll past the 100th file shown.

UI-wise this could be achieved by either "hiding" older history in a "older than 6 months" filter the same we do for the visited sites history. Alternatively, we could have a drop-down that would allow to load the latest 10,20,50,100 files and split the history in "pages". 

PS: my downloads.sqlite file is nearly 5MB in size, but most of the files that I've downloaded are either renamed/moved or deleted from their original download location.

PPS: This is not a duplicate of bug 270312, since it also happens with files of known size. They just need to be large enough so that the download goes on for enough time for someone to notice the issue.

Comment 5

[Kurt Jaeke]

Did you check the dl speed of the download? I also see extremely high CPU usage, but only for really fast downloads. I have CPU usage of 50% for 2.5MiB/s.

BTW:
Mozilla/5.0 (Macintosh; Intel Mac OS X 10.6; rv:10.0.2) Gecko/20100101 Firefox/10.0.2

Comment 6

[Andrej Hribernik]

Hi,

I am also experiencing high cpu usage when downloading files. 

The easiest way I am able to repeat this by

- clear all cache and history
- go into private browsing mode 
- download many (20 to 30 in number)
- files must be large (20MB-400MB) 
- files are of known size 
- downloads are via HTTP
- download rate is about 20-300kb/s for each file
- close all firefox tabs and windows, only the download manager window is open

CPU usage goes up to about 30%, interestingly the CPU usage HALVES to about 15% when i minimise the download manager window, maximising it causes it to go back up to 30%.

I had accidentally left my browser in private mode when I first noticed this issue, I haven't investigated further in normal browsing mode.

Firefox version : Mozilla/5.0 (Macintosh; Intel Mac OS X 10.7; rv:11.0) Gecko/20100101 Firefox/11.0
Add-ons installed: Flashblock plus, flashgot

System Info:
  Model Name:		MacBook Air
  Model Identifier:	MacBookAir4,2
  Processor Name:	Intel Core i5
  Processor Speed:	1.7 GHz
  Memory:			4GB
  OS :			Mac OS X Lion 10.7.3

Comment 7

[klonos]

Any news on this one?

Comment 8

[u279076]

Resolving this as DUPE of bug 397424 since this is clearly the same issue and it has more recent information. It doesn't help to debug this in several places independently. Anyone with this issue please move over to bug 397424. We are still trying to track down an internally reproducible testcase after all these years. Your help is appreciated.