User Agent: Mozilla/5.0 (Windows NT 6.3; WOW64; rv:42.0) Gecko/20100101 Firefox/42.0 Build ID: 20150715030207 Steps to reproduce: 1) Enter agar.io games 2) Play the game 3) Observe the game getting hitches and drop of frames (jank) *Attaching a performance recording while playing on my machine. Actual results: The games drops frames and gets pretty janky at times. Expected results: Maintain a smooth 60fps gameplay without drop of frames.

did you test with e10s enabled or disabled?

I tried it with e10s enabled and disabled and did find it a little sluggish both ways. Mozilla/5.0 (Windows NT 6.3; Win64; x64; rv:42.0) Gecko/20100101 Firefox/42.0 Graphics -------- Adapter Description: AMD Radeon R9 200 / HD 7900 Series Adapter Drivers: aticfx64 aticfx64 aticfx64 aticfx32 aticfx32 aticfx32 atiumd64 atidxx64 atidxx64 atiumdag atidxx32 atidxx32 atiumdva atiumd6a atitmm64 Adapter RAM: 3072 Asynchronous Pan/Zoom: none ClearType Parameters: D [ Gamma: 2200 Pixel Structure: R ClearType Level: 100 Enhanced Contrast: 300 ] D [ Gamma: 2200 Pixel Structure: R ClearType Level: 50 Enhanced Contrast: 100 ] Device ID: 0x6798 Direct2D Enabled: true DirectWrite Enabled: true (6.3.9600.17795) Driver Date: 6-22-2015 Driver Version: 15.200.1046.0 GPU #2 Active: false GPU Accelerated Windows: 1/1 Direct3D 11 (OMTC) Subsys ID: 00000000 Supports Hardware H264 Decoding: true Vendor ID: 0x1002 WebGL Renderer: Google Inc. -- ANGLE (AMD Radeon R9 200 / HD 7900 Series Direct3D11 vs_5_0 ps_5_0) windowLayerManagerRemote: true AzureCanvasBackend: direct2d 1.1 AzureContentBackend: direct2d 1.1 AzureFallbackCanvasBackend: cairo AzureSkiaAccelerated: 0

(In reply to Loic from comment #1) > did you test with e10s enabled or disabled? I have tested this with e10 enabled.

Me and mfinkle second this. mfinkle said this: 12:49 mfinkle works great on chrome, crappy on Firefox 12:50 mfinkle it seems like gc pauses happen, ruining the game play

This is still a major issue in Firefox 43. As soon as multiple blobs come in, it is super janky.

To test this in a more controlled environment, use a local instance of https://github.com/OgarProject/Ogar and load agar.io?ip=127.0.0.1: and the port Ogar is listening on. Running commands like addbot on the server helps control the parameters of the game and the load on the rendering engine. For a game like agar.io avoiding jank is very important.. I also think it's a question of GC timing/duration, so tweaking is better left to experts, but if there's any more analysis or logging I can help with..

Can someone please retest this with the latest Firefox Nightly? If it's still janky, please capture a performance profile and GC profile using the built in Developer Tools. If this is GC related then it doesn't belong in Graphics.

i captured a profile from latest Nightly.

I have tested this with e10 enabled. http://bagario.net running well

Slither.io also plays very choppily in Firefox 56.0a1 (2017-07-30) (64-bit nightly build). Plays very well in Chrome. It becomes more exaggerated on lower mid-end laptops (I use a HP Pavillion g7-1277dx with AMD 3530MX processor), especially in linux. Sluggish canvas rendering is one of the last things keeping me from using Firefox full-time, aside from that it has pretty much caught up to chrome.