Re: [PATCH v2] x86/tsc: Set X86_FEATURE_TSC_RELIABLE to skip refined calibration

2016-10-12 Thread Thomas Gleixner
On Tue, 11 Oct 2016, Bin Gao wrote: > On Fri, Aug 26, 2016 at 12:14:58PM +0200, Thomas Gleixner wrote: > > The Linux kernel does think a reliable calibration implies the reliability > (i.e. > no watchdog required). I'm posting some code pieces to explain. I know that and I know exactly how all

Re: [PATCH v2] x86/tsc: Set X86_FEATURE_TSC_RELIABLE to skip refined calibration

2016-10-11 Thread Bin Gao
On Fri, Aug 26, 2016 at 12:14:58PM +0200, Thomas Gleixner wrote: > On Fri, 26 Aug 2016, Thomas Gleixner wrote: > > On Thu, 25 Aug 2016, Bin Gao wrote: > > > On Wed, Aug 24, 2016 at 10:51:20AM +0200, Thomas Gleixner wrote: > > > > On Tue, 16 Aug 2016, Bin Gao wrote: > > > > > On some newer Intel

Re: [PATCH v2] x86/tsc: Set X86_FEATURE_TSC_RELIABLE to skip refined calibration

2016-08-26 Thread Thomas Gleixner
On Fri, 26 Aug 2016, Thomas Gleixner wrote: > On Thu, 25 Aug 2016, Bin Gao wrote: > > On Wed, Aug 24, 2016 at 10:51:20AM +0200, Thomas Gleixner wrote: > > > On Tue, 16 Aug 2016, Bin Gao wrote: > > > > On some newer Intel x86 processors/SoCs the TSC frequency can be > > > > directly > > > >

Re: [PATCH v2] x86/tsc: Set X86_FEATURE_TSC_RELIABLE to skip refined calibration

2016-08-26 Thread Thomas Gleixner
On Thu, 25 Aug 2016, Bin Gao wrote: > On Wed, Aug 24, 2016 at 10:51:20AM +0200, Thomas Gleixner wrote: > > On Tue, 16 Aug 2016, Bin Gao wrote: > > > On some newer Intel x86 processors/SoCs the TSC frequency can be directly > > > calculated by factors read from specific MSR registers or from a

Re: [PATCH v2] x86/tsc: Set X86_FEATURE_TSC_RELIABLE to skip refined calibration

2016-08-25 Thread Bin Gao
On Wed, Aug 24, 2016 at 10:51:20AM +0200, Thomas Gleixner wrote: > On Tue, 16 Aug 2016, Bin Gao wrote: > > On some newer Intel x86 processors/SoCs the TSC frequency can be directly > > calculated by factors read from specific MSR registers or from a cpuid > > leaf (0x15). TSC frequency calculated

Re: [PATCH v2] x86/tsc: Set X86_FEATURE_TSC_RELIABLE to skip refined calibration

2016-08-24 Thread Thomas Gleixner
On Tue, 16 Aug 2016, Bin Gao wrote: > On some newer Intel x86 processors/SoCs the TSC frequency can be directly > calculated by factors read from specific MSR registers or from a cpuid > leaf (0x15). TSC frequency calculated by native msr/cpuid is absolutely > accurate so we should always skip