Benchmarking Ubuntu's Low-Latency Kernel & Liquorix Post-Meltdown

[AndyChow]

If you want the hardware to be in charge, why not use none then?

Because noop does request merges. So it can define sequential requests while it's in queue. It just doesn't schedule anything.

[deusexmachina]

Here's how one can achieve real smoothness:

- Use openSUSE Tumbleweed, since it contains the best Linux Kernel config by default. (250Hz tick timer, PREEMPT enabled)

- Use the deadline İO scheduler.

- Use the 'performance' governor.

- Additionally, if stuck on İntel, make sure to set the 'performance-bias' to '0'!

Now enjoy your silky-smooth Linux experience!

Why not 1000hz?

https://serverfault.com/questions/377947/1000-hz-linux-kernel-necessary-if-i-have-tickless-and-high-resolution-timer

I'll have to check how many of these settings are used in Arch by default...

[Linuxxx]

Why not 1000hz?
https://serverfault.com/questions/37...solution-timer

I'll have to check how many of these settings are used in Arch by default...

Note that was what I used back then...

Nowadays I just run Ubuntu 18.04 LTS with the "lowlatency" kernel. (Which does have a 1000 Hz timer tick, by the way.)

[deusexmachina]

Note that was what I used back then...

Nowadays I just run Ubuntu 18.04 LTS with the "lowlatency" kernel. (Which does have a 1000 Hz timer tick, by the way.)

After reading these benchmarks I realize I understand even less about what CONFIG_HZ actually does:

https://passthroughpo.st/config_hz-how-does-it-affect-kvm/

Seems 1000hz isn't necessarily the lowest latency, for example.

[Linuxxx]

After reading these benchmarks I realize I understand even less about what CONFIG_HZ actually does:

https://passthroughpo.st/config_hz-how-does-it-affect-kvm/

Seems 1000hz isn't necessarily the lowest latency, for example.

I think you missed the most important part from that link you posted:

Overall, 1000Hz nets better minimum framerates.
...
It is advisable to pick 1000Hz over 100Hz or 250Hz in order to receive a small but tangible minimum framerate improvement while gaming.

So, 1000 Hz is clearly the best, no matter how you look at it!

[deusexmachina]

I think you missed the most important part from that link you posted:


So, 1000 Hz is clearly the best, no matter how you look at it!

OK, but *why* does config_hz = 1000hz consistently increase frame rate? Especially since 250hz shows decreased latency in other benchmarks... It isn't clear to me how it works.