summaryrefslogtreecommitdiffstats
path: root/ipc
diff options
context:
space:
mode:
authorSuresh Siddha <suresh.b.siddha@intel.com>2012-10-22 23:37:58 +0200
committerThomas Gleixner <tglx@linutronix.de>2012-11-02 11:23:37 +0100
commit279f1461432ccdec0b98c0bcbe0a8e2c0f6fdda5 (patch)
tree1adaa912a846b6d45cff5c8b03db8f97d30ac779 /ipc
parentMerge git://git.kernel.org/pub/scm/linux/kernel/git/nab/target-pending (diff)
downloadlinux-279f1461432ccdec0b98c0bcbe0a8e2c0f6fdda5.tar.xz
linux-279f1461432ccdec0b98c0bcbe0a8e2c0f6fdda5.zip
x86: apic: Use tsc deadline for oneshot when available
If the TSC deadline mode is supported, LAPIC timer one-shot mode can be implemented using IA32_TSC_DEADLINE MSR. An interrupt will be generated when the TSC value equals or exceeds the value in the IA32_TSC_DEADLINE MSR. This enables us to skip the APIC calibration during boot. Also, in xapic mode, this enables us to skip the uncached apic access to re-arm the APIC timer. As this timer ticks at the high frequency TSC rate, we use the TSC_DIVISOR (32) to work with the 32-bit restrictions in the clockevent API's to avoid 64-bit divides etc (frequency is u32 and "unsigned long" in the set_next_event(), max_delta limits the next event to 32-bit for 32-bit kernel). Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com> Cc: venki@google.com Cc: len.brown@intel.com Link: http://lkml.kernel.org/r/1350941878.6017.31.camel@sbsiddha-desk.sc.intel.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'ipc')
0 files changed, 0 insertions, 0 deletions