Re: [PATCH RFC V2 3/5] kvm hypervisor : Add two hypercalls to support pv-ticketlock

On 10/26/2011 09:08 PM, Raghavendra K T wrote:

On 10/26/2011 04:04 PM, Avi Kivity wrote:

quoted

On 10/25/2011 08:24 PM, Raghavendra K T wrote:

CCing Ryan also

quoted

quoted

So then do also you foresee the need for directed yield at some point,
to address LHP? provided we have good improvements to prove.

Doesn't this patchset completely eliminate lock holder preemption?

Basically I was curious whether we can do more better with your
directed yield discussions in https://lkml.org/lkml/2010/8/2/106 .

I felt we can get little more improvement with doing directed yield to
lock-holder in case of LHP than sleeping. But I may be wrong.

So wanted to get the feedback, on whether I am thinking in right
direction.

i guess donating some time to the lock holder could help, but not by
much. The problem with non-pv spinlocks is that you can't just sleep,
since no one will wake you up, so you have to actively boost the lock
holder.

-- 
I have a truly marvellous patch that fixes the bug which this
signature is too narrow to contain.