From mboxrd@z Thu Jan  1 00:00:00 1970
From: Raghavendra K T <raghukt@linux.vnet.ibm.com>
Subject: Re: [PATCH RFC V2 3/5] kvm hypervisor : Add two hypercalls to support
 pv-ticketlock
Date: Thu, 27 Oct 2011 00:38:13 +0530
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Cc: Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com>,
	Raghavendra K T <raghavendra.kt@linux.vnet.ibm.com>,
	Greg Kroah-Hartman <gregkh@suse.de>,
	"H. Peter Anvin" <hpa@zytor.com>, Gleb Natapov <gleb@redhat.com>,
	Virtualization <virtualization@lists.linux-foundation.org>,
	Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>,
	x86@kernel.org, KVM <kvm@vger.kernel.org>,
	Dave Jiang <dave.jiang@intel.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Stefano Stabellini <stefano.stabellini@eu.citrix.com>,
	Xen <xen-devel@lists.xensource.com>,
	Sedat Dilek <sedat.dilek@gmail.com>,
	Yinghai Lu <yinghai@kernel.org>,
	Marcelo Tosatti <mtosatti@redhat.com>,
	Ingo Molnar <mingo@redhat.com>, Rik van Riel <riel@redhat.com>,
	Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
	LKML <linux-kernel@vger.kernel.org>,
	Suzuki Poulose <suzuki@linux.vnet.ibm.com>,
	Peter Zijlstra <peterz@infradead.org>,
	Ryan Harper
To: Avi Kivity <avi@redhat.com>
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On 10/26/2011 04:04 PM, Avi Kivity wrote:
> On 10/25/2011 08:24 PM, Raghavendra K T wrote:
CCing Ryan also
>>
>> 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.