Messages in this thread | | | Date | Wed, 13 Apr 2016 11:53:26 -0400 | From | Waiman Long <> | Subject | Re: [PATCH] powerpc: introduce {cmp}xchg for u8 and u16 |
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On 04/13/2016 07:15 AM, Pan Xinhui wrote: > Hello Peter, > > On 2016年04月12日 22:30, Peter Zijlstra wrote: > >>> I am working on the qspinlock implementation on PPC. >>> Your and Waiman's patches are so nice. :) >> Thanks!, last time I looked at PPC spinlocks they could not use things >> like ticket locks because PPC might be a guest and fairness blows etc.. >> >> You're making the qspinlock-paravirt thing work on PPC, or doing >> qspinlock only for bare-metal PPC? >> > I am making the both work. :) > qspinlock works on PPC now. I am preparing the patches and will send them out in next weeks :)
What of performance improvement are you seeing in PPC?
> The paravirt work is a little hard. > currently, there are pv_wait() and pv_kick(). but only pv_kick has the parameter cpu(who will hold the lock as soon as the lock is unlocked). > We need parameter cpu(who holds the lock now) in pv_wait,too.
That can be doable to a certain extent. However, if the current lock holder acquired the lock via the fastpath only. The CPU information is not logged anywhere. For a contended lock, the information should be there.
Cheers, Longman
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