ipq40xx: switch to performance governor by default
authorKoen Vandeputte <koen.vandeputte@citymesh.com>
Tue, 12 Sep 2023 13:38:27 +0000 (15:38 +0200)
committerKoen Vandeputte <koen.vandeputte@citymesh.com>
Fri, 20 Oct 2023 13:17:21 +0000 (15:17 +0200)
Doing a simple ping to my device shows this:

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

Some users even report higher values on older kernels:

64 bytes from seq=0 ttl=64 time=0.612 ms
64 bytes from seq=1 ttl=64 time=2.852 ms
64 bytes from seq=2 ttl=64 time=2.719 ms
64 bytes from seq=3 ttl=64 time=2.741 ms
64 bytes from 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 icmp_seq=1 ttl=64 time=0.528 ms
64 bytes from icmp_seq=2 ttl=64 time=0.561 ms
64 bytes from icmp_seq=3 ttl=64 time=0.633 ms
64 bytes from 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):

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

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 VARĂˆNE <hacks@slashdirt.org>
Signed-off-by: Koen Vandeputte <koen.vandeputte@citymesh.com>
(cherry picked from commit b8e52852bd62236a2a84663b4592d221ebc64cb4)


index 0acc013a813083c485b90f29c382b18bf9f808be..d08f4e0a24d7f11465a7dfc9fb56bda39c225f11 100644 (file)
@@ -67,8 +67,8 @@ CONFIG_CPU_COPY_V6=y