6.12.0-1-cachyos-server kernel significant performance loss

Issues & Assistance
1

After upgrading the kernel from 6.11, there is a significant loss of performance. My hardware is a bunch of ancient decommissioned servers on 2011v3 socket on v4 processors, so I use v3 repository. For example, when transcoding video via svt-av1 (very CPU and memory intensive) there is a 5-10% performance loss. I built a 6.12.0 kernel, changing the following things:

CONFIG_HZ_250=y
CONFIG_PREEMPT_NONE=y
(and disabled dynamic preempt)

After these changes, the problem disappeared.
PS: I really use arch linux with zfs for production servers

2

Seems like PREEMPT_LAZY is not the saviour to throughput as we thought, will fix this in 6.12.2

1 Like
3

Checked kernels in games. The kernel built with preempt none shows the best results…

4

No performance regression after update. Consider also building with CONFIG_HZ_100 or CONFIG_HZ_250, as some tasks had better results with CONFIG_HZ_100