openwrt/target/linux
Koen Vandeputte b8e52852bd ipq40xx: switch to performance governor by default
Doing a simple ping to my device shows this:

64 bytes from 10.0.253.101: icmp_seq=1 ttl=64 time=2.00 ms
64 bytes from 10.0.253.101: icmp_seq=2 ttl=64 time=2.02 ms
64 bytes from 10.0.253.101: icmp_seq=3 ttl=64 time=1.68 ms
64 bytes from 10.0.253.101: icmp_seq=4 ttl=64 time=1.91 ms
64 bytes from 10.0.253.101: icmp_seq=5 ttl=64 time=1.92 ms
64 bytes from 10.0.253.101: icmp_seq=6 ttl=64 time=2.04 ms

Some users even report higher values on older kernels:

64 bytes from 192.168.1.10: seq=0 ttl=64 time=0.612 ms
64 bytes from 192.168.1.10: seq=1 ttl=64 time=2.852 ms
64 bytes from 192.168.1.10: seq=2 ttl=64 time=2.719 ms
64 bytes from 192.168.1.10: seq=3 ttl=64 time=2.741 ms
64 bytes from 192.168.1.10: seq=4 ttl=64 time=2.808 ms

The problem is that the governor is set to Ondemand, which causes
the CPU to clock all the way down to 48MHz in some cases.

Switching to performance governor:

64 bytes from 10.0.253.101: icmp_seq=1 ttl=64 time=0.528 ms
64 bytes from 10.0.253.101: icmp_seq=2 ttl=64 time=0.561 ms
64 bytes from 10.0.253.101: icmp_seq=3 ttl=64 time=0.633 ms
64 bytes from 10.0.253.101: icmp_seq=4 ttl=64 time=0.526 ms

In theory, using the Performance governor should increase power draw,
but it looks like it really does not matter for this soc.

Using a calibrated precision DC power supply (cpu idle):

Ondemand
24.00V * 0.134A = 3.216 Watts
48.00V * 0.096A = 4.608 Watts

Performance
24.00V * 0.135A = 3.240 Watts
48.00V * 0.096A = 4.608 Watts

Let's simply switch to the Performance governor by default
to fix the general jittery behaviour on devices using this soc.

Tested on: MikroTik wAP ac

Fixes: #13649
Reviewed-by: Robert Marko <robimarko@gmail.com>
Reviewed-by: Thibaut VARÈNE <hacks@slashdirt.org>
Signed-off-by: Koen Vandeputte <koen.vandeputte@citymesh.com>
2023-10-20 15:11:41 +02:00
..
airoha
apm821xx
archs38
armsr armsr: preserve configuration during sysupgrade 2023-10-20 00:36:32 +02:00
at91
ath25
ath79
bcm27xx
bcm47xx
bcm53xx
bcm63xx
bcm4908
bmips
gemini
generic generic: kernel: add missing symbol 2023-10-19 12:12:02 +02:00
imx
ipq40xx ipq40xx: switch to performance governor by default 2023-10-20 15:11:41 +02:00
ipq806x
kirkwood
lantiq
layerscape layerscape: kernel: refresh 6.1 patches 2023-10-19 12:39:08 +02:00
malta
mediatek
mpc85xx
mvebu
mxs
octeon
octeontx
omap
oxnas
pistachio
qoriq
qualcommax
ramips Revert "ramips: convert MT7915 EEPROM to NVMEM format" 2023-10-17 20:57:07 +08:00
realtek
rockchip
sifiveu
sunxi
tegra
uml
x86
zynq
Makefile