[elrepo] Where should I go to find kernel issues?

[Akemi Yagi]

On Thu, Jan 16, 2014 at 9:34 AM, Joshua Kramer <joskra42.list at gmail.com> wrote:
> So I found out that starting with 3.4 I think, the kernel defaults to using
> the intel_pstate driver instead of acpi_pstate.  If using the intel_pstate
> driver causes issues (as it did with me), then add this to the kernel boot
> parameters:
>
> intel_pstate=disable
>
> After doing this, my copy of the 3.12 kernel now uses the acpi driver, and
> things work as they should.
>
> Of course, using acpi has its drawbacks.  Depending on processor capability,
> sometimes a longer-running task at low frequency uses more power than a fast
> task at a high frequency.  The intel_pstate driver knows about this and
> accomodates.  The issue is that intel_pstate does not use the same governor
> options as acpi; with intel_pstate, there are only powersave and
> performance.
>
> So in this case, the "right" solution for users of EL clones is to go hunt
> down the configurations for the cpuspeed daemon and modify it to not try to
> set the scaling_governor to something that is not allowed.
>
> This post has more information:
> https://bbs.archlinux.org/viewtopic.php?pid=1294415#p1294415

Thank you for posting a followup with useful information. Just as a
data point, the kernel in RHEL 7 beta (3.10.0-54.0.1.el7) has the
following config entries:

CONFIG_CPU_FREQ=y
CONFIG_CPU_FREQ_TABLE=y
CONFIG_CPU_FREQ_GOV_COMMON=y
CONFIG_CPU_FREQ_STAT=m
CONFIG_CPU_FREQ_STAT_DETAILS=y
# CONFIG_CPU_FREQ_DEFAULT_GOV_PERFORMANCE is not set
# CONFIG_CPU_FREQ_DEFAULT_GOV_USERSPACE is not set
CONFIG_CPU_FREQ_DEFAULT_GOV_ONDEMAND=y
# CONFIG_CPU_FREQ_DEFAULT_GOV_CONSERVATIVE is not set
CONFIG_CPU_FREQ_GOV_PERFORMANCE=y
CONFIG_CPU_FREQ_GOV_POWERSAVE=y
CONFIG_CPU_FREQ_GOV_USERSPACE=y
CONFIG_CPU_FREQ_GOV_ONDEMAND=y
CONFIG_CPU_FREQ_GOV_CONSERVATIVE=y
CONFIG_X86_PCC_CPUFREQ=m
CONFIG_X86_ACPI_CPUFREQ=m
CONFIG_X86_ACPI_CPUFREQ_CPB=y

versus the kernel in RHEL 6.5 (2.6.32-431.el6)

CONFIG_CPU_FREQ=y
CONFIG_CPU_FREQ_TABLE=m
CONFIG_CPU_FREQ_DEBUG=y
CONFIG_CPU_FREQ_STAT=m
CONFIG_CPU_FREQ_STAT_DETAILS=y
# CONFIG_CPU_FREQ_DEFAULT_GOV_PERFORMANCE is not set
# CONFIG_CPU_FREQ_DEFAULT_GOV_POWERSAVE is not set
CONFIG_CPU_FREQ_DEFAULT_GOV_USERSPACE=y
# CONFIG_CPU_FREQ_DEFAULT_GOV_ONDEMAND is not set
# CONFIG_CPU_FREQ_DEFAULT_GOV_CONSERVATIVE is not set
CONFIG_CPU_FREQ_GOV_PERFORMANCE=y
CONFIG_CPU_FREQ_GOV_POWERSAVE=m
CONFIG_CPU_FREQ_GOV_USERSPACE=y
CONFIG_CPU_FREQ_GOV_ONDEMAND=m
CONFIG_CPU_FREQ_GOV_CONSERVATIVE=m
CONFIG_X86_PCC_CPUFREQ=m
CONFIG_X86_ACPI_CPUFREQ=m

Akemi