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From: Waiman Long <waiman.long@hp.com>
To: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>,
	Raghavendra K T <raghavendra.kt@linux.vnet.ibm.com>,
	kvm@vger.kernel.org, Peter Zijlstra <peterz@infradead.org>,
	virtualization@lists.linux-foundation.org,
	Andi Kleen <andi@firstfloor.org>,
	"H. Peter Anvin" <hpa@zytor.com>,
	Michel Lespinasse <walken@google.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	linux-arch@vger.kernel.org, Gleb Natapov <gleb@redhat.com>,
	x86@kernel.org, Ingo Molnar <mingo@redhat.com>,
	xen-devel@lists.xenproject.org,
	"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
	Rik van Riel <riel@redhat.com>, Arnd Bergmann <arnd@arndb.de>,
	Scott J Norton <scott.norton@hp.com>,
	Steven Rostedt <rostedt@goodmis.org>,
	Chris Wright <chrisw@sous-sol.org>,
	Oleg Nesterov <oleg@redhat.com>,
	Alok Kataria <akataria@vmware.com>,
	Aswin Chandramouleeswaran <aswin@hp.com>,
	Chegu Vinod <chegu_vinod@hp.com>,
	Boris Ostrovsky <boris.ostrovsky>
Subject: Re: [PATCH v7 02/11] qspinlock, x86: Enable x86-64 to use queue spinlock
Date: Thu, 20 Mar 2014 23:36:29 -0400	[thread overview]
Message-ID: <532BB3BD.80905@hp.com> (raw)
In-Reply-To: <20140319202405.GA11210@phenom.dumpdata.com>

On 03/19/2014 04:24 PM, Konrad Rzeszutek Wilk wrote:
> On Wed, Mar 19, 2014 at 04:14:00PM -0400, Waiman Long wrote:
>> This patch makes the necessary changes at the x86 architecture
>> specific layer to enable the use of queue spinlock for x86-64. As
>> x86-32 machines are typically not multi-socket. The benefit of queue
>> spinlock may not be apparent. So queue spinlock is not enabled.
>>
>> Currently, there is some incompatibilities between the para-virtualized
>> spinlock code (which hard-codes the use of ticket spinlock) and the
>> queue spinlock. Therefore, the use of queue spinlock is disabled when
>> the para-virtualized spinlock is enabled.
> And how does this patch do that? I think that comment is obsolete?

This comment is true wrt patch 2. As you add more patches on top, the 
limitation is removed.

-Longman

WARNING: multiple messages have this Message-ID (diff)
From: Waiman Long <waiman.long@hp.com>
To: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>,
	Raghavendra K T <raghavendra.kt@linux.vnet.ibm.com>,
	kvm@vger.kernel.org, Peter Zijlstra <peterz@infradead.org>,
	virtualization@lists.linux-foundation.org,
	Andi Kleen <andi@firstfloor.org>,
	"H. Peter Anvin" <hpa@zytor.com>,
	Michel Lespinasse <walken@google.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	linux-arch@vger.kernel.org, Gleb Natapov <gleb@redhat.com>,
	x86@kernel.org, Ingo Molnar <mingo@redhat.com>,
	xen-devel@lists.xenproject.org,
	"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
	Rik van Riel <riel@redhat.com>, Arnd Bergmann <arnd@arndb.de>,
	Scott J Norton <scott.norton@hp.com>,
	Steven Rostedt <rostedt@goodmis.org>,
	Chris Wright <chrisw@sous-sol.org>,
	Oleg Nesterov <oleg@redhat.com>,
	Alok Kataria <akataria@vmware.com>,
	Aswin Chandramouleeswaran <aswin@hp.com>,
	Chegu Vinod <chegu_vinod@hp.com>,
	Boris Ostrovsky <boris.ostrovsky
Subject: Re: [PATCH v7 02/11] qspinlock, x86: Enable x86-64 to use queue spinlock
Date: Thu, 20 Mar 2014 23:36:29 -0400	[thread overview]
Message-ID: <532BB3BD.80905@hp.com> (raw)
In-Reply-To: <20140319202405.GA11210@phenom.dumpdata.com>

On 03/19/2014 04:24 PM, Konrad Rzeszutek Wilk wrote:
> On Wed, Mar 19, 2014 at 04:14:00PM -0400, Waiman Long wrote:
>> This patch makes the necessary changes at the x86 architecture
>> specific layer to enable the use of queue spinlock for x86-64. As
>> x86-32 machines are typically not multi-socket. The benefit of queue
>> spinlock may not be apparent. So queue spinlock is not enabled.
>>
>> Currently, there is some incompatibilities between the para-virtualized
>> spinlock code (which hard-codes the use of ticket spinlock) and the
>> queue spinlock. Therefore, the use of queue spinlock is disabled when
>> the para-virtualized spinlock is enabled.
> And how does this patch do that? I think that comment is obsolete?

This comment is true wrt patch 2. As you add more patches on top, the 
limitation is removed.

-Longman

  reply	other threads:[~2014-03-21  3:36 UTC|newest]

Thread overview: 51+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-03-19 20:13 [PATCH v7 00/11] qspinlock: a 4-byte queue spinlock with PV support Waiman Long
2014-03-19 20:13 ` [PATCH v7 01/11] qspinlock: A generic 4-byte queue spinlock implementation Waiman Long
2014-03-19 20:13 ` Waiman Long
2014-03-19 20:14 ` [PATCH v7 02/11] qspinlock, x86: Enable x86-64 to use queue spinlock Waiman Long
2014-03-19 20:14 ` Waiman Long
2014-03-19 20:24   ` Konrad Rzeszutek Wilk
2014-03-19 20:24   ` Konrad Rzeszutek Wilk
2014-03-19 20:24     ` Konrad Rzeszutek Wilk
2014-03-21  3:36     ` Waiman Long [this message]
2014-03-21  3:36       ` Waiman Long
2014-03-21  3:36     ` Waiman Long
2014-03-19 20:14 ` [PATCH v7 03/11] qspinlock: More optimized code for smaller NR_CPUS Waiman Long
2014-03-19 20:14 ` Waiman Long
2014-03-19 20:14 ` [PATCH v7 04/11] qspinlock: Optimized code path for 2 contending tasks Waiman Long
2014-03-19 20:14 ` Waiman Long
2014-03-19 20:14 ` [PATCH v7 05/11] pvqspinlock, x86: Allow unfair spinlock in a PV guest Waiman Long
2014-03-19 20:14 ` Waiman Long
2014-03-19 20:14 ` [PATCH v7 06/11] pvqspinlock, x86: Allow unfair queue spinlock in a KVM guest Waiman Long
2014-03-19 20:14 ` Waiman Long
2014-03-20 22:01   ` Paolo Bonzini
2014-03-20 22:01     ` Paolo Bonzini
2014-03-20 22:29     ` H. Peter Anvin
2014-03-20 22:29     ` H. Peter Anvin
2014-03-20 22:29       ` H. Peter Anvin
2014-03-20 22:40       ` Paolo Bonzini
2014-03-20 22:40       ` Paolo Bonzini
2014-03-20 22:40         ` Paolo Bonzini
2014-03-21 21:27     ` Waiman Long
2014-03-21 21:27     ` Waiman Long
2014-03-20 22:01   ` Paolo Bonzini
2014-03-19 20:14 ` [PATCH v7 07/11] pvqspinlock, x86: Allow unfair queue spinlock in a XEN guest Waiman Long
2014-03-19 20:14 ` Waiman Long
2014-03-19 20:28   ` Konrad Rzeszutek Wilk
2014-03-19 20:28   ` Konrad Rzeszutek Wilk
2014-03-19 20:28     ` Konrad Rzeszutek Wilk
2014-03-21  3:40     ` Waiman Long
2014-03-21  3:40     ` Waiman Long
2014-03-21  3:40       ` Waiman Long
2014-03-19 20:14 ` [PATCH v7 08/11] pvqspinlock, x86: Rename paravirt_ticketlocks_enabled Waiman Long
2014-03-19 20:14 ` Waiman Long
2014-03-19 20:14 ` [PATCH v7 09/11] pvqspinlock, x86: Add qspinlock para-virtualization support Waiman Long
2014-03-19 20:14 ` Waiman Long
2014-03-19 20:14 ` [PATCH v7 10/11] pvqspinlock, x86: Enable qspinlock PV support for KVM Waiman Long
2014-03-20 22:07   ` Paolo Bonzini
2014-03-20 22:07     ` Paolo Bonzini
2014-03-21 21:41     ` Waiman Long
2014-03-21 21:41     ` Waiman Long
2014-03-20 22:07   ` Paolo Bonzini
2014-03-19 20:14 ` Waiman Long
2014-03-19 20:14 ` [PATCH RFC v7 11/11] pvqspinlock, x86: Enable qspinlock PV support for XEN Waiman Long
2014-03-19 20:14 ` Waiman Long

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