On Wed, 2020-08-05 at 11:34 +0200, Rafael J. Wysocki wrote: > Hi Doug, > > On Tue, Aug 4, 2020 at 7:07 PM Doug Smythies <dsmythies@xxxxxxxxx> > wrote: > > Hi Rafael, > > > > [...] > Note that the active mode performance scaling algorithm (which is not > the same as the performance cpufreq governor) sets the EPP to 0 for > all of the CPUs that it is used with and the driver sets the EPP to > 255 in ->stop_cpu. > > That last bit is questionable, but that's the active mode behavior > which is not changed by the $subject patch. You need to set the CPU which is going offline to the lowest perf settings. If not its sibling's performance can never be lowered than offlined CPUs max/min/epp. Thanks, Srinivas > > It would be more reasonable to restore the previous EPP when stopping > CPUs. Let me cut a v7 with that changed. > > > # /home/doug/c/msr-decoder > > How many CPUs?: 6 > > 8.) 0x198: IA32_PERF_STATUS : CPU 0-5 : 46 : 46 : 46 : 46 > > : 46 : 46 : > > B.) 0x770: IA32_PM_ENABLE: 1 : HWP enable > > 1.) 0x19C: IA32_THERM_STATUS: 88450000 > > 2.) 0x1AA: MSR_MISC_PWR_MGMT: 401CC0 EIST enabled Coordination > > enabled OOB Bit 8 reset OOB Bit 18 reset > > 3.) 0x1B1: IA32_PACKAGE_THERM_STATUS: 88430000 > > 4.) 0x64F: MSR_CORE_PERF_LIMIT_REASONS: 0 > > A.) 0x1FC: MSR_POWER_CTL: 3C005D : C1E disable : EEO disable : RHO > > disable > > 5.) 0x771: IA32_HWP_CAPABILITIES (performance): 109252E : high 46 : > > guaranteed 37 : efficient 9 : lowest 1 > > 6.) 0x774: IA32_HWP_REQUEST: CPU 0-5 : > > raw: 00002E2E : 00002E2E : 00002E2E : 00002E2E : 00002E2E : > > 00002E2E : > > min: 46 : 46 : 46 : 46 : 46 > > : 46 : > > max: 46 : 46 : 46 : 46 : 46 > > : 46 : > > des: 0 : 0 : 0 : 0 : 0 > > : 0 : > > epp: 0 : 0 : 0 : 0 : 0 > > : 0 : > > act: 0 : 0 : 0 : 0 : 0 > > : 0 : > > 7.) 0x777: IA32_HWP_STATUS: 4 : high 4 : guaranteed 0 : efficient 0 > > : lowest 0 > > > > and then switched to passive mode later. EPP is not as expected. > > Expect 0 > > (performance mode): > > > > # /home/doug/c/msr-decoder > > How many CPUs?: 6 > > 8.) 0x198: IA32_PERF_STATUS : CPU 0-5 : 46 : 46 : 46 : 46 > > : 46 : 46 : > > B.) 0x770: IA32_PM_ENABLE: 1 : HWP enable > > 1.) 0x19C: IA32_THERM_STATUS: 88440000 > > 2.) 0x1AA: MSR_MISC_PWR_MGMT: 401CC0 EIST enabled Coordination > > enabled OOB Bit 8 reset OOB Bit 18 reset > > 3.) 0x1B1: IA32_PACKAGE_THERM_STATUS: 88420000 > > 4.) 0x64F: MSR_CORE_PERF_LIMIT_REASONS: 0 > > A.) 0x1FC: MSR_POWER_CTL: 3C005D : C1E disable : EEO disable : RHO > > disable > > 5.) 0x771: IA32_HWP_CAPABILITIES (performance): 108252E : high 46 : > > guaranteed 37 : efficient 8 : lowest 1 > > 6.) 0x774: IA32_HWP_REQUEST: CPU 0-5 : > > raw: FF002E2E : FF002E2E : FF002E2E : FF002E2E : FF002E2E : > > FF002E2E : > > min: 46 : 46 : 46 : 46 : 46 > > : 46 : > > max: 46 : 46 : 46 : 46 : 46 > > : 46 : > > des: 0 : 0 : 0 : 0 : 0 > > : 0 : > > epp: 255 : 255 : 255 : 255 : 255 > > : 255 : > > act: 0 : 0 : 0 : 0 : 0 > > : 0 : > > 7.) 0x777: IA32_HWP_STATUS: 4 : high 4 : guaranteed 0 : efficient 0 > > : lowest 0 > > The 0xFF EPP value is what the active mode left behind and the > passive > mode doesn't touch the EPP at all. > > > Then switched to ondemand governor, and put 100% load on 2 CPUs. > > EPP is not as expected, which I don't actually know what to expect, > > but assume 128: > > > > # /home/doug/c/msr-decoder > > How many CPUs?: 6 > > 8.) 0x198: IA32_PERF_STATUS : CPU 0-5 : 46 : 46 : 46 : 46 > > : 46 : 46 : > > B.) 0x770: IA32_PM_ENABLE: 1 : HWP enable > > 1.) 0x19C: IA32_THERM_STATUS: 883B0000 > > 2.) 0x1AA: MSR_MISC_PWR_MGMT: 401CC0 EIST enabled Coordination > > enabled OOB Bit 8 reset OOB Bit 18 reset > > 3.) 0x1B1: IA32_PACKAGE_THERM_STATUS: 882B0000 > > 4.) 0x64F: MSR_CORE_PERF_LIMIT_REASONS: 0 > > A.) 0x1FC: MSR_POWER_CTL: 3C005D : C1E disable : EEO disable : RHO > > disable > > 5.) 0x771: IA32_HWP_CAPABILITIES (performance): 10B252E : high 46 : > > guaranteed 37 : efficient 11 : lowest 1 > > 6.) 0x774: IA32_HWP_REQUEST: CPU 0-5 : > > raw: FF002E09 : FF002E0C : FF002E2E : FF002E08 : FF002E2E : > > FF002E18 : > > min: 9 : 12 : 46 : 8 : 46 > > : 24 : > > max: 46 : 46 : 46 : 46 : 46 > > : 46 : > > des: 0 : 0 : 0 : 0 : 0 > > : 0 : > > epp: 255 : 255 : 255 : 255 : 255 > > : 255 : > > act: 0 : 0 : 0 : 0 : 0 > > : 0 : > > 7.) 0x777: IA32_HWP_STATUS: 4 : high 4 : guaranteed 0 : efficient 0 > > : lowest 0 > > It is still 0xFF as previously (because the passive mode doesn't > change the EPP). > > > For what it's worth, Kernel: > > > > 78b39581ed85 (HEAD -> dtemp) cpufreq: intel_pstate: Implement > > passive mode with HWP enabled > > c0842fbc1b18 (origin/master, origin/HEAD, master) random32: move > > the pseudo-random 32-bit definitions to prandom.h > > 2baa85d6927d Merge tag 'acpi-5.9-rc1' of > > git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm > > 04084978003c Merge tag 'pm-5.9-rc1' of > > git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm > > Thanks!
