[tuned] #42: tuned profile CPU governor controls must account for CPU generation
#42: tuned profile CPU governor controls must account for CPU generation
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Reporter: jeder | Owner:
Type: defect | Status: new
Priority: major | Component: daemon
Version: 2.0 | Keywords:
Blocked By: | Blocking:
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tuned profiles currently utilize CPU "governors" to configure cpufreq.
With newer generation chips from Intel, this capability will go away, and
we need tuned to support both older and current generations as well as
newer generations, from different vendors such as ARM-based chips.
So the specification for functional performance levels must be abstracted,
and, based on the system hardware, would implement the required tuning.
For example, newer generations of Intel CPUs default to the intel_pstate
driver upstream and in Fedora. In order for tuned to handle these Sandy
Bridge and newer chips, it will need to be taught about the intel_pstate
driver, which has different knobs in sysfs.
Setting governor=ondemand will be useless on systems where the kernel
detects newer Intel chips and thus uses intel_pstate.
For example, tuned could key off of the model number in /proc/cpuinfo (or
similar).
model : 45
model name : Intel(R) Xeon(R) CPU E5-2630 0 @ 2.30GHz
Then if it finds a certain Intel model number or greater, it would skip
setting ondemand. Ondemand is the new default of intel_pstate.
$ for i in `find /sys/devices/system/cpu/intel_pstate -type f` ; do echo
-n "$i: " ; cat $i ; done
/sys/devices/system/cpu/intel_pstate/max_perf_pct: 100
/sys/devices/system/cpu/intel_pstate/no_turbo: 0
/sys/devices/system/cpu/intel_pstate/min_perf_pct: 31
All profiles that contain governor=performance have to set
min_perf_pct=100. The default is currently 31.
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Ticket URL: <https://fedorahosted.org/tuned/ticket/42>
tuned <https://fedorahosted.org/tuned/>
A daemon that performs monitoring and adaptive configuration of devices in the system.