Re: [PATCH] cpufreq: intel_pstate: Disable interrupts during MSRs reading

2014-04-29 Thread Rafael J. Wysocki
On Tuesday, April 29, 2014 08:46:05 PM Stratos Karafotis wrote: > According to Intel 64 and IA-32 Architectures SDM, Volume 3, > Chapter 14.2, "Software needs to exercise care to avoid delays > between the two RDMSRs (for example interrupts)". > > So, disable interrupts during reading MSRs

[PATCH] cpufreq: intel_pstate: Disable interrupts during MSRs reading

2014-04-29 Thread Stratos Karafotis
According to Intel 64 and IA-32 Architectures SDM, Volume 3, Chapter 14.2, "Software needs to exercise care to avoid delays between the two RDMSRs (for example interrupts)". So, disable interrupts during reading MSRs IA32_APERF and IA32_MPERF. Since the TSC is also takes place in the calculation

[PATCH] cpufreq: intel_pstate: Disable interrupts during MSRs reading

2014-04-29 Thread Stratos Karafotis
According to Intel 64 and IA-32 Architectures SDM, Volume 3, Chapter 14.2, Software needs to exercise care to avoid delays between the two RDMSRs (for example interrupts). So, disable interrupts during reading MSRs IA32_APERF and IA32_MPERF. Since the TSC is also takes place in the calculation

Re: [PATCH] cpufreq: intel_pstate: Disable interrupts during MSRs reading

2014-04-29 Thread Rafael J. Wysocki
On Tuesday, April 29, 2014 08:46:05 PM Stratos Karafotis wrote: According to Intel 64 and IA-32 Architectures SDM, Volume 3, Chapter 14.2, Software needs to exercise care to avoid delays between the two RDMSRs (for example interrupts). So, disable interrupts during reading MSRs IA32_APERF