On 03/23/2016 04:05 PM, Len Brown wrote: > This patch assumes that if a package state is disabled, > the corresponding core state must be disabled. > That assumption is false. > Indeed, that is a very popular and useful configuration. > > But even if that were not the case, this software is not necessary, > since the hardware handles demotion "c-state clipping" automatically. > > Yes, there is a case where a certain version of a certain processor > has broken demotion, but this isn't the right fix for that. > The right fix for that is here: > > https://bugzilla.kernel.org/show_bug.cgi?id=109081
Len, should I rebase on top of this? Would that work for you? P. > > and will be upstream shortly. > > thanks, > -Len > > > > On Mon, Mar 21, 2016 at 8:49 AM, Prarit Bhargava <pra...@redhat.com> wrote: >> Some Intel processors have cstates limited by MSR_PKG_CST_CONFIG_CONTROL >> (0xE2), which specifies the lowest processor-specific C-state code name >> (consuming the least power). The intel_idle driver does not query this MSR >> to >> see if states are limited by hardware. In the case of the i7-6700HQ the >> value >> of bits 3:0 on the MSR are 0x6, meaning that C9-SKL (0x7) and C10-SKL (0x8) >> should have been disabled. >> >> This patch adds a limit field to the cpuidle_state struct to hold the >> cstate encodings for each processor, and queries the values the values >> to confirm support. >> >> After applying this patchset the system now boots and reports that >> some states have been disabled: >> >> [root@dhcp40-125 ~]# dmesg | grep intel_idle >> [ 1.163367] intel_idle: MWAIT substates: 0x11142120 >> [ 1.163368] intel_idle: v0.4 model 0x5E >> [ 1.163369] intel_idle: lapic_timer_reliable_states 0xffffffff >> [ 1.163370] intel_idle: state C9-SKL (0x7) is disabled. Max Package >> limit is 0x6. >> [ 1.163371] intel_idle: state C10-SKL (0x8) is disabled. Max Package >> limit is 0x6. >> >> Cc: x...@kernel.org >> Cc: Len Brown <l...@kernel.org> >> Cc: "Peter Zijlstra (Intel)" <pet...@infradead.org> >> Cc: Borislav Petkov <b...@suse.de> >> Cc: Andi Kleen <a...@linux.intel.com> >> Cc: Alexander Shishkin <alexander.shish...@linux.intel.com> >> Cc: Dasaratharaman Chandramouli <dasaratharaman.chandramo...@intel.com> >> Cc: linux...@vger.kernel.org >> Signed-off-by: Prarit Bhargava <pra...@redhat.com> >> >> Prarit Bhargava (3): >> idle, rename MSR_NHM_SNB_PKG_CST_CFG_CTL to >> MSR_PKG_CST_CONFIG_CONTROL >> intel_idle, Introduce cstate limits and fix hardware cstate disable >> value >> cpuidle, Prevent users from enabling cstates that are disabled in >> Hardware >> >> arch/x86/include/asm/msr-index.h | 2 +- >> drivers/cpuidle/governors/ladder.c | 3 ++ >> drivers/cpuidle/governors/menu.c | 4 ++ >> drivers/cpuidle/sysfs.c | 34 +++++++++++- >> drivers/idle/intel_idle.c | 93 >> ++++++++++++++++++++++++++++++++- >> include/linux/cpuidle.h | 11 +++- >> tools/power/x86/turbostat/turbostat.8 | 2 +- >> tools/power/x86/turbostat/turbostat.c | 10 ++-- >> 8 files changed, 146 insertions(+), 13 deletions(-) >> >> -- >> 1.7.9.3 >> > > >
