Commit 8fdcca8e authored by Linus Walleij's avatar Linus Walleij Committed by Rafael J. Wysocki

cpufreq: Select schedutil when using big.LITTLE

When we are using a system with big.LITTLE HMP
configuration, we need to use EAS to schedule the
system.

As can be seen from kernel/sched/topology.c:

 "EAS can be used on a root domain if it meets all the following conditions:
  1. an Energy Model (EM) is available;
  2. the SD_ASYM_CPUCAPACITY flag is set in the sched_domain hierarchy.
  3. no SMT is detected.
  4. the EM complexity is low enough to keep scheduling overheads low;
  5. schedutil is driving the frequency of all CPUs of the rd;"

This means that at the very least, schedutil needs to be
available as a scheduling policy for EAS to work on these
systems. Make this explicit by defaulting to the schedutil
governor if BIG_LITTLE is selected.

Currently users of the TC2 board (like me) has to figure these
dependencies out themselves and it is not helpful.
Suggested-by: default avatarArnd Bergmann <arnd@arndb.de>
Signed-off-by: default avatarLinus Walleij <linus.walleij@linaro.org>
Acked-by: default avatarSudeep Holla <sudeep.holla@arm.com>
Acked-by: default avatarViresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
parent a00ec387
...@@ -37,6 +37,7 @@ config CPU_FREQ_STAT ...@@ -37,6 +37,7 @@ config CPU_FREQ_STAT
choice choice
prompt "Default CPUFreq governor" prompt "Default CPUFreq governor"
default CPU_FREQ_DEFAULT_GOV_USERSPACE if ARM_SA1100_CPUFREQ || ARM_SA1110_CPUFREQ default CPU_FREQ_DEFAULT_GOV_USERSPACE if ARM_SA1100_CPUFREQ || ARM_SA1110_CPUFREQ
default CPU_FREQ_DEFAULT_GOV_SCHEDUTIL if BIG_LITTLE
default CPU_FREQ_DEFAULT_GOV_SCHEDUTIL if X86_INTEL_PSTATE && SMP default CPU_FREQ_DEFAULT_GOV_SCHEDUTIL if X86_INTEL_PSTATE && SMP
default CPU_FREQ_DEFAULT_GOV_PERFORMANCE default CPU_FREQ_DEFAULT_GOV_PERFORMANCE
help help
......
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