[openwrt/openwrt] ipq40xx: switch to performance governor by default

[LEDE Commits]

xback pushed a commit to openwrt/openwrt.git, branch openwrt-23.05:
https://git.openwrt.org/4afff7b8b54c3b246fba30ed83dfac527e78e57d

commit 4afff7b8b54c3b246fba30ed83dfac527e78e57d
Author: Koen Vandeputte <koen.vandeputte at citymesh.com>
AuthorDate: Tue Sep 12 15:38:27 2023 +0200

    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 at gmail.com>
    Reviewed-by: Thibaut VARÈNE <hacks at slashdirt.org>
    Signed-off-by: Koen Vandeputte <koen.vandeputte at citymesh.com>
    (cherry picked from commit b8e52852bd62236a2a84663b4592d221ebc64cb4)
---
 target/linux/ipq40xx/config-5.15 | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/target/linux/ipq40xx/config-5.15 b/target/linux/ipq40xx/config-5.15
index 0acc013a81..d08f4e0a24 100644
--- a/target/linux/ipq40xx/config-5.15
+++ b/target/linux/ipq40xx/config-5.15
@@ -67,8 +67,8 @@ CONFIG_CPU_COPY_V6=y
 CONFIG_CPU_CP15=y
 CONFIG_CPU_CP15_MMU=y
 CONFIG_CPU_FREQ=y
-CONFIG_CPU_FREQ_DEFAULT_GOV_ONDEMAND=y
-# CONFIG_CPU_FREQ_DEFAULT_GOV_PERFORMANCE is not set
+# CONFIG_CPU_FREQ_DEFAULT_GOV_ONDEMAND is not set
+CONFIG_CPU_FREQ_DEFAULT_GOV_PERFORMANCE=y
 CONFIG_CPU_FREQ_GOV_ATTR_SET=y
 CONFIG_CPU_FREQ_GOV_COMMON=y
 # CONFIG_CPU_FREQ_GOV_CONSERVATIVE is not set