• Vikas Shivappa's avatar
    x86/intel_rdt/mba_sc: Add initialization support · 1bd2a63b
    Vikas Shivappa authored
    When MBA software controller is enabled, a per domain storage is required
    for user specified bandwidth in "MBps" and the "percentage" values which
    are programmed into the IA32_MBA_THRTL_MSR. Add support for these data
    structures and initialization.
    
    The MBA percentage values have a default max value of 100 but however the
    max value in MBps is not available from the hardware so it's set to
    U32_MAX.
    
    This simply says that the control group can use all bandwidth by default
    but does not say what is the actual max bandwidth available. The actual
    bandwidth that is available may depend on lot of factors like QPI link,
    number of memory channels, memory channel frequency, its width and memory
    speed, how many channels are configured and also if memory interleaving is
    enabled. So there is no way to determine the maximum at runtime reliably.
    Signed-off-by: default avatarVikas Shivappa <vikas.shivappa@linux.intel.com>
    Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
    Cc: ravi.v.shankar@intel.com
    Cc: tony.luck@intel.com
    Cc: fenghua.yu@intel.com
    Cc: vikas.shivappa@intel.com
    Cc: ak@linux.intel.com
    Cc: hpa@zytor.com
    Link: https://lkml.kernel.org/r/1524263781-14267-4-git-send-email-vikas.shivappa@linux.intel.com
    1bd2a63b
intel_rdt.c 21.6 KB