Hi Dave, Actually in my test lab which is a HP box running CentOS 7 on kernel version 3.10.0-693.5.2.el7.x86_64, the default cpufreq driver is pcc_cpufreq. So I guess disabling intel_pstate wouldn't help in my case.
# cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_driver pcc-cpufreq # cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_available_governors conservative userspace powersave ondemand performance According to kernel doc, pcc_cpufreq also doesn't export scaling_availabe_frequencies in sysfs. >From kernel doc: "scaling_available_frequencies is not created in /sys. No intermediate frequencies need to be listed because the BIOS will try to achieve any frequency, within limits, requested by the governor. A frequency does not have to be strictly associated with a P-state." The lack of scaling_availabe_frequencies makes power_acpi_cpufreq_init() complains, similar to the problem with intel_pstate as in the other thread. I have tried (though with not much effort) to force the kernel to use acpi-cpufreq instead but without success. Luckily, as quoted above pcc_cpufreq supports setting of arbitrary frequency, so a simple workaround for now is to fake a scaling_available_frequencies file in another directory, then edit the code in librte_power to use that file instead. Regards, -BL > -----Original Message----- > From: david.h...@intel.com [mailto:david.h...@intel.com] > Sent: Monday, March 5, 2018 5:16 PM > To: long...@viettel.com.vn; dev@dpdk.org > Subject: Re: [dpdk-dev] librte_power w/ intel_pstate cpufreq governor > > Hi BL, > > I have always used "intel_pstate=disable" in my kernel parameters at boot so > as to disable the intel_pstate driver, and force the kernel to use the acpi- > cpufreq driver: > > # cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_driver > acpi-cpufreq > > This then gives me the following options for the governor: > ['conservative', 'ondemand', 'userspace', 'powersave', 'performance', > 'schedutil'] > > Because DPDK threads typically poll, they appear as 100% busy to the p_state > driver, so if you want to be able to change core frequency down (as in l3fwd- > power), you need to use the acpi-cpufreq driver. > > I had a read through the docs just now, and this does not seem to be > mentioned, so I'll do up a patch to give some information on the correct > kernel parameters to use when using the power library. > > Regards, > Dave. > > On 2/3/2018 7:20 AM, long...@viettel.com.vn wrote: > > Forgot to link the original thread. > > > > http://dpdk.org/ml/archives/dev/2016-January/030930.html > > > > -BL > > > >> -----Original Message----- > >> From: long...@viettel.com.vn [mailto:long...@viettel.com.vn] > >> Sent: Friday, March 2, 2018 2:19 PM > >> To: dev@dpdk.org > >> Cc: david.h...@intel.com; mh...@mhcomputing.net; > >> helin.zh...@intel.com; long...@viettel.com.vn > >> Subject: librte_power w/ intel_pstate cpufreq governor > >> > >> Hi everybody, > >> > >> I know this thread was from over 2 years ago but I ran into the same > > problem > >> with l3fwd-power today. > >> > >> Any updates on this? > >> > >> -BL > >
