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From: David Vrabel <david.vrabel@citrix.com>
To: Peter Zijlstra <peterz@infradead.org>, <Waiman.Long@hp.com>
Cc: <raghavendra.kt@linux.vnet.ibm.com>, <kvm@vger.kernel.org>,
	<linux-kernel@vger.kernel.org>, <hpa@zytor.com>,
	<boris.ostrovsky@oracle.com>, <linux-arch@vger.kernel.org>,
	<x86@kernel.org>, <mingo@redhat.com>, <doug.hatch@hp.com>,
	<xen-devel@lists.xenproject.org>, <paulmck@linux.vnet.ibm.com>,
	<riel@redhat.com>, <scott.norton@hp.com>,
	<paolo.bonzini@gmail.com>, <tglx@linutronix.de>,
	<virtualization@lists.linux-foundation.org>, <oleg@redhat.com>,
	<luto@amacapital.net>, <david.vrabel@citrix.com>,
	<torvalds@linux-foundation.org>
Subject: Re: [Xen-devel] [PATCH 0/9] qspinlock stuff -v15
Date: Mon, 16 Mar 2015 14:08:58 +0000	[thread overview]
Message-ID: <5506E3FA.7040304@citrix.com> (raw)
In-Reply-To: <20150316131613.720617163@infradead.org>

On 16/03/15 13:16, Peter Zijlstra wrote:
> Hi Waiman,
> 
> As promised; here is the paravirt stuff I did during the trip to BOS last week.
> 
> All the !paravirt patches are more or less the same as before (the only real
> change is the copyright lines in the first patch).
> 
> The paravirt stuff is 'simple' and KVM only -- the Xen code was a little more
> convoluted and I've no real way to test that but it should be stright fwd to
> make work.
> 
> I ran this using the virtme tool (thanks Andy) on my laptop with a 4x
> overcommit on vcpus (16 vcpus as compared to the 4 my laptop actually has) and
> it both booted and survived a hackbench run (perf bench sched messaging -g 20
> -l 5000).
> 
> So while the paravirt code isn't the most optimal code ever conceived it does work.
> 
> Also, the paravirt patching includes replacing the call with "movb $0, %arg1"
> for the native case, which should greatly reduce the cost of having
> CONFIG_PARAVIRT_SPINLOCKS enabled on actual hardware.
> 
> I feel that if someone were to do a Xen patch we can go ahead and merge this
> stuff (finally!).

I can look at this.  It looks pretty straight-forward.

> These patches do not implement the paravirt spinlock debug stats currently
> implemented (separately) by KVM and Xen, but that should not be too hard to do
> on top and in the 'generic' code -- no reason to duplicate all that.

I think this is fine.

David

  parent reply	other threads:[~2015-03-16 14:09 UTC|newest]

Thread overview: 43+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-03-16 13:16 Peter Zijlstra
2015-03-16 13:16 ` [PATCH 1/9] qspinlock: A simple generic 4-byte queue spinlock Peter Zijlstra
2015-03-16 13:16 ` [PATCH 2/9] qspinlock, x86: Enable x86-64 to use " Peter Zijlstra
2015-03-16 13:16 ` [PATCH 3/9] qspinlock: Add pending bit Peter Zijlstra
2015-03-16 13:16 ` [PATCH 4/9] qspinlock: Extract out code snippets for the next patch Peter Zijlstra
2015-03-16 13:16 ` [PATCH 5/9] qspinlock: Optimize for smaller NR_CPUS Peter Zijlstra
2015-03-16 13:16 ` [PATCH 6/9] qspinlock: Use a simple write to grab the lock Peter Zijlstra
2015-03-16 13:16 ` [PATCH 7/9] qspinlock: Revert to test-and-set on hypervisors Peter Zijlstra
2015-03-16 13:16 ` [PATCH 8/9] qspinlock: Generic paravirt support Peter Zijlstra
     [not found]   ` <5509E51D.7040909@hp.com>
2015-03-19 10:12     ` Peter Zijlstra
2015-03-19 12:25       ` Peter Zijlstra
2015-03-19 13:43         ` Peter Zijlstra
2015-03-19 23:25         ` Waiman Long
2015-04-01 16:20         ` Waiman Long
2015-04-01 17:12           ` Peter Zijlstra
2015-04-01 17:42             ` Peter Zijlstra
2015-04-01 18:17               ` Peter Zijlstra
2015-04-01 18:54                 ` Waiman Long
2015-04-01 18:48                   ` Peter Zijlstra
2015-04-01 19:58                     ` Waiman Long
2015-04-01 21:03                       ` Peter Zijlstra
2015-04-02 16:28                         ` Waiman Long
2015-04-02 17:20                           ` Peter Zijlstra
2015-04-02 19:48                             ` Peter Zijlstra
2015-04-03  3:39                               ` Waiman Long
2015-04-03 13:43                               ` Peter Zijlstra
2015-04-01 20:10             ` Waiman Long
2015-03-16 13:16 ` [PATCH 9/9] qspinlock,x86,kvm: Implement KVM support for paravirt qspinlock Peter Zijlstra
     [not found]   ` <550A3863.2060808@hp.com>
2015-03-19 10:01     ` Peter Zijlstra
2015-03-19 21:08       ` Waiman Long
2015-03-20  7:43         ` Raghavendra K T
2015-03-16 14:08 ` David Vrabel [this message]
2015-03-18 20:36 ` [PATCH 0/9] qspinlock stuff -v15 Waiman Long
2015-03-19 18:01 ` [Xen-devel] " David Vrabel
2015-03-19 18:32   ` Peter Zijlstra
2015-03-25 19:47 ` Konrad Rzeszutek Wilk
2015-03-26 20:21   ` Peter Zijlstra
2015-03-27 14:07     ` Konrad Rzeszutek Wilk
2015-03-30 16:41       ` Waiman Long
2015-03-30 16:25   ` Waiman Long
2015-03-30 16:29     ` Peter Zijlstra
2015-03-30 16:43       ` Waiman Long
2015-03-27  6:40 ` Raghavendra K T

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