Messages in this thread | | | Date | Tue, 15 Oct 2013 23:45:58 +0200 | From | Sander Eikelenboom <> | Subject | Kconfig help entry for CONFIG_PARAVIRT_SPINLOCK |
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Hi Raghavendra,
Since the ticketlock series have landed in this mergewindow (thanks :-) ) the help accompanying the Kconfig entry doesn't seem to reflect the current state well.
- Wasn't the whole purpose of the ticketlock series to mitigate this 5% performance hit to something far less, so distro kernels could enable this for their normal kernels ? I don't have the exact performance figures though.
- Perhaps the suggestion to enable this for supported hypervisors (Xen and KVM ?) could be added ?
-- Sander
CONFIG_PARAVIRT_SPINLOCKS:
Paravirtualized spinlocks allow a pvops backend to replace the spinlock implementation with something virtualization-friendly (for example, block the virtual CPU rather than spinning).
Unfortunately the downside is an up to 5% performance hit on native kernels, with various workloads.
If you are unsure how to answer this question, answer N.
Symbol: PARAVIRT_SPINLOCKS [=y] Type : boolean Prompt: Paravirtualization layer for spinlocks Location: -> Processor type and features -> Linux guest support (HYPERVISOR_GUEST [=y]) -> Enable paravirtualization code (PARAVIRT [=y]) Defined at arch/x86/Kconfig:632 Depends on: HYPERVISOR_GUEST [=y] && PARAVIRT [=y] && SMP [=y] Selects: UNINLINE_SPIN_UNLOCK [=y]
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