1320745 - Download speeds limited on gigabit internet connection

Status: UNCONFIRMED

(Core :: Networking, defect, P3)

Description

[Adam Pieniazek]

User Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.11; rv:52.0) Gecko/20100101 Firefox/52.0
Build ID: 20161128004004

Steps to reproduce:

Either visit a speed test site like fast.com or download a large file ( e.g. Ubunti ISO ). In Firefox Developer Edition and consumer Firefox 52 speeds are limited to about 300Mbps whereas in Chrome, Safari and Opera speeds reach 850-900 Mbps. Tests done via gigabit ethernet and via Wifi with same results. Confirmed across multiple machines and connections.


Actual results:

Large files take 2-3 times longer to download in Firefox than in Chrome/Opera/Safari. The only test where I saw gigabit speeds in Firefox was in http://beta.speedtest.net/result/5834698839. But on fast.com and in real world download tests Firefox was 2 to 3 times slower and did not approach gigabit speeds.


Expected results:

Files should take approximately the same amount of time to download and fast.com should report similar speeds. Speeds should approach gigabit speeds 900+ Mbps but instead see about 300 Mbps in Firefox while other browsers download at gigabit speeds.

Comment 1

[Dragana Damjanovic [:dragana]]

Which OS are you using?

Can you make wireshark cap? It would help me figure out if tcp is limited. (you can also send it via e-mail)

Http logging would be good as well. how to obtain it is described at:
https://developer.mozilla.org/en-US/docs/Mozilla/Debugging/HTTP_logging
and please replace line:
export MOZ_LOG=timestamp,rotate:200,nsHttp:5,nsSocketTransport:5,nsStreamPump:5,nsHostResolver:5
with
export MOZ_LOG=timestamp,nsHttp:5,nsSocketTransport:5,nsStreamPump:5,nsHostResolver:5

Thank you!

Comment 2

[Firefox Bug Husbandry Bot]

Bulk change to priority: https://bugzilla.mozilla.org/show_bug.cgi?id=1399258

Comment 3

[Firefox Bug Husbandry Bot]

Bulk change to priority: https://bugzilla.mozilla.org/show_bug.cgi?id=1399258

Comment 4

[bugs]

here is a similar issue, can anyone repro or confirm it? https://bugzilla.mozilla.org/show_bug.cgi?id=1444681

Comment 5

[sephula]

Attachment: Speedtest.7z

Ookla Speedtest.net results comparison for Firefox 70 on both, Windows 10 1903, and Linux Mint 19.2 with multiple browsers & desktop and CLI apps.

Comment 6

[sephula]

Comment on attachment 9105959 [details]
Speedtest.7z

Ookla speedtest results comparison for Firefox 70 on both, Windows 10 1903, and Linux Mint 19.2 with multiple browsers & desktop and CLI apps.

Comment 7

[sephula]

I can confirm that I'm experiencing the same issue in Windows 10 1903 (64-bit) and Linux Mint 19.2 64-bit Cinnamon. My download speed seems to be limited to around 300 Mbps using Firefox 70.0.1 (64-bit) on Windows 10. The situations is just a little bit better on Linux Mint. I've noticed that all browsers seems to suffer some performance penalty vs the Ookla desktop app and CLI tool. The straight desktop app seems to get the best performance. Chrome and Brave get about the same, which is slightly less. Firefox's speed is pitiful vs its competition. Obviously, this will need to be rectified as we're about to enter the 10Gbase-T era. I don't see how Firefox can expect to continue without a major overhaul and speed boost.

Comment 8

[Loreno Heer]

Same problem here Windows 7 64-bit. Firefox is limited to 300 Mbps. Chrome reaches ~920 Mbps.

Comment 9

[Loreno Heer]

Also this problem seems only to appear over HTTPS, over HTTP the regular speed of 920 ish is achieved.

Comment 10

[u680648]

(In reply to Loreno Heer from comment #9)

Also this problem seems only to appear over HTTPS, over HTTP the regular speed of 920 ish is achieved.

I can confirm this speed limit issue. Firefox's download speed is throttled at 250mbps for me using the latest Firefox 64-bit. And as Loreno Heer said above, it appears to only affect HTTPS sites, not HTTP. This bug has been submitted over four years ago and still not resolved. Please see the support thread I made about this bug for more info: https://support.mozilla.org/en-US/questions/1327222