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From: Arnd Bergmann <arnd@arndb•de>
To: linuxppc-dev@ozlabs•org
Cc: hollisb@us•ibm.com, kvm-ppc@vger•kernel.org
Subject: Re: [PATCH 4/4] kvmppc: convert wrteei to wrtee as kvm guest optimization
Date: Tue, 19 Aug 2008 13:42:29 +0200	[thread overview]
Message-ID: <200808191342.29918.arnd@arndb.de> (raw)
In-Reply-To: <1219142204-12044-5-git-send-email-ehrhardt@linux.vnet.ibm.com>

On Tuesday 19 August 2008, ehrhardt@linux•vnet.ibm.com wrote:
> Dependent on the already existing CONFIG_KVM_GUEST config option this patch
> changes wrteei to wrtee allowing the hypervisor to rewrite those to nontrapping
> instructions. Maybe we should split the kvm guest otpimizations in two parts
> one for the overhead free optimizations and on for the rest that might add
> some complexity for non virtualized execution (like this one).
> 
> Signed-off-by: Christian Ehrhardt <ehrhardt@linux•vnet.ibm.com>

How significant is the performance impact of this change for non-virtualized
systems? If it's very low, maybe you should not bother with the #ifdef, and
if it's noticable, you might be better off using dynamic patching for this.

	Arnd <><

  reply	other threads:[~2008-08-19 11:44 UTC|newest]

Thread overview: 28+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-08-19 10:36 [PATCH 0/4][RFC] kvmppc: paravirtualization interface - guest part v2 ehrhardt
2008-08-19 10:36 ` [PATCH 1/4] kvmppc: read device tree hypervisor node infrastructure ehrhardt
2008-08-19 11:52   ` Josh Boyer
2008-08-19 11:56     ` Josh Boyer
2008-08-19 10:36 ` [PATCH 2/4] kvmppc: add hypercall infrastructure - guest part ehrhardt
2008-08-19 11:28   ` Arnd Bergmann
2008-08-20 12:41     ` Christian Ehrhardt
2008-08-21 22:25     ` Hollis Blanchard
2008-08-22 10:38   ` Kumar Gala
2008-08-22 14:00     ` Hollis Blanchard
2008-08-19 10:36 ` [PATCH 3/4] kvmppc: magic page paravirtualization " ehrhardt
2008-08-20  2:29   ` Tony Breeds
2008-08-19 10:36 ` [PATCH 4/4] kvmppc: convert wrteei to wrtee as kvm guest optimization ehrhardt
2008-08-19 11:42   ` Arnd Bergmann [this message]
2008-08-20 12:53     ` Christian Ehrhardt
2008-08-20 18:30       ` Hollis Blanchard
2008-08-20 18:52         ` Josh Boyer
2008-08-20 19:06           ` Hollis Blanchard
2008-08-20 19:18             ` Josh Boyer
2008-08-21 13:31               ` Christian Ehrhardt
2008-08-21 13:41   ` Kumar Gala
2008-08-21 14:13     ` Christian Ehrhardt
2008-08-21 14:21       ` Kumar Gala
2008-08-21 16:16         ` Scott Wood
2008-08-22  8:08           ` Christian Ehrhardt
2008-08-22  8:17             ` Kumar Gala
2008-08-22 13:56               ` Jimi Xenidis
2008-08-22 15:49                 ` Scott Wood

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