Awesome Anandtech article about Input Lag

[Benfica]

Exploring Input Lag Inside and Out

Some topics:
- Reflexes and Input Generation / Human Reaction Time.
- megapixels/second mouse dpi, maximum speed, reports/per second. Mouse software creates way more lag than hardware
- Parsing Input in Software and the CPU Limit, USB hubs, Human Interface service, windows messages, game code interpreting input
- CPU and GPU limitations. Kind of operations more prone to lag: game state and logic, display lists and draw calls, texturing, etc...
- Monitor lag: refresh rate, ports (DVI, HDMI and DisplayPort). VSync, buffering, transmission. Great videos illustrating 2 games, CRT and TFT, with and w/o vsync recorded with high speed camera.

Lots more and very detailed!

[Moloko]

Anandtech : "There will be games that optimize for reducing input lag and others that do not"

Carmack and Valve seem to be taking this seriously. I hope Epic are , UT3 has always felt inherently less responsive than previous UTs , both on and offline.

[BlueCloud]

Right now the biggest problem is that WAR servers(maybe vCTF servers too) with lot of players have SERVER lag which EPIC won't/can't fix, which we all can't do much about, except request server providers to upgrade CPU and reduce other servers/programs running. :/

And if the server provider is EPIC, I guess we are left with no avail. US Epic Warfare #2 goes from 50 ping with 4 players playing to 140 ping with 32 players playing. This never happened in 2k4, ONS or otherwise.

[Moloko]

It's hard to believe server lag was even worse before patch 2.0, is it just me or did the lag issue seem to dramatically improve with 2.0, only to now come back with a vengeance?

off topic The game server browser, it takes 2 refreshes to show anything like correct ping and the options (show players names etc.) don't always function.

Also if I disconnect it's not possible to rejoin the game I was in ...a time out issue? Your name is still in the player's names window, as if still playing. This would also explain the unusually large numbers of players you see in UT3 standing around idle.

[PR0V0]

Nice tip! Gonna check it out right away!

[Goldenadder]

I get lots of input lag in UT3 on and offline using Vista OS. I would commonly see 35-100ms input lag making the game unplayable at times. What's strange is that when I switch to Windows 7 RC I get no input lag spikes at all. I get a steady 13-16ms of input lag on Windows 7 RC. The only differences I could find between the two is the Direct x 10 version 6.00.6001.1800 on Vista and Direct x 11 version 6.01.7100.0000 on Windows 7 RC. Perhaps it's something within the direct x drivers for me...I can't confirm.

[ThaMarine]

US Epic Warfare #2 goes from 50 ping with 4 players playing to 140 ping with 32 players playing.

140 with 32 players!!!!!!!!!!!!????????

I'd give my left nut for that ping!

[shombowhore]

140 with 32 players!!!!!!!!!!!!????????

I'd give my left nut for that ping!

That's a bad ping tho, lol. : (

[BlueCloud]

140 with 32 players!!!!!!!!!!!!????????

I'd give my left nut for that ping!

I used to get 40 ping to a CTF UT2k4 server in Chicago. So, three times the regular ping just because it's warfare and a full server coz of server lag sucks.

[Moloko]

I used to get 40 ping to a CTF UT2k4 server in Chicago. So, three times the regular ping just because it's warfare and a full server coz of server lag sucks.

I've seen servers that I normally ping at around 70, go out to 160 when full. Obviously the server has to sync everyone, but players above a certain ping level(200?) IIRC, are auto kicked, so the, poor pinger pushing eveyone's up explanation isn't the reason?

[Ga-Reef]

That's a bad ping tho, lol. : (

That's everyday ping for me, which why I will NEVER EVER be able to pull off a moving shock combo. Otherwise I'd simply change my name to Combo King.

[BlueCloud]

I've seen servers that I normally ping at around 70, go out to 160 when full. Obviously the server has to sync everyone, but players above a certain ping level(200?) IIRC, are auto kicked, so the, poor pinger pushing eveyone's up explanation isn't the reason?

This is a popular myth that seems to be getting repeated. If someone has a high ping, it does NOT affect other people's ping. Just that player along will be lagged(sometimes you can see the player skipping, this is due to high lag or packetloss). I've regularly played on UT2004 CTF servers where some player's ping was 250 but mine was at 40 and I never lagged. The server doesn't wait for a player's input while syncing. It just calculates(at the tick rate) based on the input already received.

The real reason you go from 70 ping to 160 as the server fills up is that the servers CPU is unable to handle UT3's warfare/vctf calculations. I have also heard that UT3's server code is bad at multithreading on multi-CPU servers. UT2004 onslaught does not have this problem. So either the server providers need to get faster CPUs or reduce other game servers running, or Epic needs to fix UT3 server code. The PUB Warfare server used to go to only 90 ping with 24 players playing because that was a private box, not a highly shared server like UMG.

[Moloko]

s. I have also heard that UT3's server code is bad at multithreading on multi-CPU servers. UT2004 onslaught does not have this problem. So either the server providers need to get faster CPUs or reduce other game servers running, or Epic needs to fix UT3 server code. The PUB Warfare server used to go to only 90 ping with 24 players playing because that was a private box, not a highly shared server like UMG.

Admins stress that the problems aren't serverside tho, in terms of weak HW or upstream bandwidth probs. As for multi threading being broken, it was stated here; due to the realtime, linear nature of the server-side world-update calculations, all code is handled sequentially only, using just one core .