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From: Paolo Bonzini <pbonzini@redhat.com>
To: Marcelo Tosatti <mtosatti@redhat.com>,
	Andy Lutomirski <luto@amacapital.net>
Cc: Gleb Natapov <gleb@kernel.org>, kvm list <kvm@vger.kernel.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"xen-devel@lists.xenproject.org" <xen-devel@lists.xenproject.org>
Subject: Re: [RFC 2/2] x86, vdso, pvclock: Simplify and speed up the vdso pvclock reader
Date: Tue, 06 Jan 2015 09:39:57 +0100	[thread overview]
Message-ID: <54AB9F5D.6070504@redhat.com> (raw)
In-Reply-To: <20150105191756.GA31201@amt.cnet>



On 05/01/2015 20:17, Marcelo Tosatti wrote:
> But there is no guarantee that vCPU-N has updated its pvti when
> vCPU-M resumes guest instruction execution.

You're right.

> So the cost this patch removes is mainly from __getcpu (==RDTSCP?) ?
> Perhaps you can use Gleb's idea to stick vcpu id into version field ?

Or just replace __getcpu with rdtscp.

Paolo

  parent reply	other threads:[~2015-01-06  8:40 UTC|newest]

Thread overview: 76+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-12-23  0:39 [RFC 0/2] x86, vdso, pvclock: Cleanups and speedups Andy Lutomirski
2014-12-23  0:39 ` [RFC 1/2] x86, vdso: Use asm volatile in __getcpu Andy Lutomirski
2014-12-23  0:39 ` Andy Lutomirski
2014-12-23  0:39 ` [RFC 2/2] x86, vdso, pvclock: Simplify and speed up the vdso pvclock reader Andy Lutomirski
2014-12-23  0:39 ` Andy Lutomirski
2014-12-23 10:28   ` [Xen-devel] " David Vrabel
2014-12-23 10:28   ` David Vrabel
2014-12-23 15:14   ` Boris Ostrovsky
2014-12-23 15:14   ` [Xen-devel] " Boris Ostrovsky
2014-12-23 15:14     ` Paolo Bonzini
2014-12-23 15:25       ` Boris Ostrovsky
2014-12-23 15:25       ` Boris Ostrovsky
2014-12-23 15:14     ` Paolo Bonzini
2014-12-24 21:30   ` David Matlack
2014-12-24 21:30   ` David Matlack
2014-12-24 21:43     ` Andy Lutomirski
2014-12-24 21:43     ` Andy Lutomirski
2015-01-05 15:25   ` Marcelo Tosatti
2015-01-05 18:56     ` Andy Lutomirski
2015-01-05 18:56     ` Andy Lutomirski
2015-01-05 19:17       ` Marcelo Tosatti
2015-01-05 19:17       ` Marcelo Tosatti
2015-01-05 22:38         ` Andy Lutomirski
2015-01-05 22:48           ` Marcelo Tosatti
2015-01-05 22:53             ` Andy Lutomirski
2015-01-05 22:53             ` Andy Lutomirski
2015-01-06  8:42             ` Paolo Bonzini
2015-01-06  8:42               ` Paolo Bonzini
2015-01-06 12:01               ` Paolo Bonzini
2015-01-06 16:56                 ` Andy Lutomirski
2015-01-06 18:13                   ` Marcelo Tosatti
2015-01-06 18:13                   ` Marcelo Tosatti
2015-01-06 18:26                     ` Andy Lutomirski
2015-01-06 18:26                     ` Andy Lutomirski
2015-01-06 18:45                       ` Marcelo Tosatti
2015-01-06 19:49                         ` Andy Lutomirski
2015-01-06 19:49                         ` Andy Lutomirski
2015-01-06 20:20                           ` Marcelo Tosatti
2015-01-06 21:54                             ` Andy Lutomirski
2015-01-06 21:54                             ` Andy Lutomirski
2015-01-06 20:20                           ` Marcelo Tosatti
2015-01-08 22:31                           ` Marcelo Tosatti
2015-01-08 22:43                             ` Andy Lutomirski
2015-02-26 22:46                               ` Andy Lutomirski
2015-02-26 22:46                               ` Andy Lutomirski
2015-01-08 22:43                             ` Andy Lutomirski
2015-01-08 22:31                           ` Marcelo Tosatti
2015-01-06 18:45                       ` Marcelo Tosatti
2015-01-07  5:41                       ` Paolo Bonzini
2015-01-07  5:41                       ` Paolo Bonzini
2015-01-07  5:38                   ` Paolo Bonzini
2015-01-07  5:38                   ` Paolo Bonzini
2015-01-07  7:18                     ` Andy Lutomirski
2015-01-07  7:18                     ` Andy Lutomirski
2015-01-07  9:00                       ` Paolo Bonzini
2015-01-07  9:00                       ` Paolo Bonzini
2015-01-07 14:45                       ` Marcelo Tosatti
2015-01-07 14:45                       ` Marcelo Tosatti
2015-01-06 16:56                 ` Andy Lutomirski
2015-01-05 22:48           ` Marcelo Tosatti
2015-01-05 22:38         ` Andy Lutomirski
2015-01-06  8:39         ` Paolo Bonzini [this message]
2015-01-06  8:39         ` Paolo Bonzini
2015-01-05 22:23       ` Paolo Bonzini
2015-01-05 22:23       ` Paolo Bonzini
2015-01-06 14:35       ` Konrad Rzeszutek Wilk
2015-01-06 14:35         ` [Xen-devel] " Konrad Rzeszutek Wilk
2015-01-05 15:25   ` Marcelo Tosatti
2015-01-08 12:51   ` David Vrabel
2015-01-08 12:51     ` [Xen-devel] " David Vrabel
2014-12-23  7:21 ` [RFC 0/2] x86, vdso, pvclock: Cleanups and speedups Paolo Bonzini
2014-12-23  7:21 ` Paolo Bonzini
2014-12-23  8:16   ` Andy Lutomirski
2014-12-23  8:16   ` Andy Lutomirski
2014-12-23  8:30     ` Paolo Bonzini
2014-12-23  8:30     ` Paolo Bonzini

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