From 31111680f6fc5f17201b02b8ce656b955be56d7a Mon Sep 17 00:00:00 2001 From: John Audia Date: Mon, 2 Sep 2024 19:53:47 -0400 Subject: [PATCH] x86: switch config to a tickless kernel This commit fixes and closes #16313. Switch the x86 kernel's timer to tickless operation which is more power efficient since it is not woken up by periodic timer interrupts when idle. Also add several other options for CPU idle governors particularly the upstream default for tickless kernels, CONFIG_CPU_IDLE_GOV_MENU. Without this commit, my AMD Ryzen 7 5800U can only achieve a minimum core frequency of 1,384 MHz which is over 3x higher than the processor's minimum frequency of 400 MHz which is accessible with this modification. In addition to the lower clock rate, I have seen a concomitant reduction in both idle temps and at-the-wall power consumption. Summary: * Idle CPU freqs dropped from 1,384 MHz to 400 Mhz. * Idle power consumption dropped from 7 W avg to 5 W. * Idle temps have dropped from 50C on avg to 43C. There are other well known reasons to switch to a tickless timer including: reduced interrupt overhead, better use of CPU resources, and reduced latency to name a few. Build system: x86/64 Build-tested: x86/64/AMD Cezanne Run-tested: x86/64/AMD Cezanne Signed-off-by: John Audia Link: https://github.com/openwrt/openwrt/pull/16317 Signed-off-by: Christian Marangi --- target/linux/x86/config-6.6 | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) diff --git a/target/linux/x86/config-6.6 b/target/linux/x86/config-6.6 index b8d38e60fa..3d1c005138 100644 --- a/target/linux/x86/config-6.6 +++ b/target/linux/x86/config-6.6 @@ -48,6 +48,7 @@ CONFIG_COMPAT_32=y CONFIG_COMPAT_32BIT_TIME=y # CONFIG_COMPAT_VDSO is not set CONFIG_CONSOLE_TRANSLATIONS=y +CONFIG_CONTEXT_TRACKING_USER_FORCE=y # CONFIG_CPU5_WDT is not set CONFIG_CPU_FREQ=y CONFIG_CPU_FREQ_DEFAULT_GOV_ONDEMAND=y @@ -61,7 +62,10 @@ CONFIG_CPU_FREQ_GOV_PERFORMANCE=y # CONFIG_CPU_FREQ_GOV_USERSPACE is not set CONFIG_CPU_FREQ_STAT=y CONFIG_CPU_IDLE=y +CONFIG_CPU_IDLE_GOV_HALTPOLL=y CONFIG_CPU_IDLE_GOV_LADDER=y +CONFIG_CPU_IDLE_GOV_MENU=y +CONFIG_CPU_IDLE_GOV_TEO=y CONFIG_CPU_MITIGATIONS=y CONFIG_CPU_SUP_AMD=y CONFIG_CPU_SUP_CENTAUR=y @@ -180,7 +184,6 @@ CONFIG_HW_RANDOM=y CONFIG_HW_RANDOM_GEODE=y CONFIG_HW_RANDOM_VIA=y # CONFIG_HYPERVISOR_GUEST is not set -CONFIG_HZ_PERIODIC=y CONFIG_I8253_LOCK=y CONFIG_IA32_FEAT_CTL=y # CONFIG_IB700_WDT is not set @@ -275,6 +278,9 @@ CONFIG_NET_XGRESS=y CONFIG_NLS=y # CONFIG_NMI_CHECK_CPU is not set # CONFIG_NOHIGHMEM is not set +CONFIG_NO_HZ=y +CONFIG_NO_HZ_COMMON=y +CONFIG_NO_HZ_FULL=y CONFIG_NR_CPUS=1 CONFIG_NR_CPUS_DEFAULT=1 CONFIG_NR_CPUS_RANGE_BEGIN=1 @@ -330,6 +336,8 @@ CONFIG_PTP_1588_CLOCK_OPTIONAL=y # CONFIG_PUNIT_ATOM_DEBUG is not set CONFIG_RANDSTRUCT_NONE=y CONFIG_RATIONAL=y +CONFIG_RCU_LAZY=y +CONFIG_RCU_NOCB_CPU_DEFAULT_ALL=y CONFIG_RD_BZIP2=y CONFIG_RD_GZIP=y CONFIG_RETHUNK=y