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 11:42:29 +0000 [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 <><
WARNING: multiple messages have this Message-ID (diff)
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 <><
next prev parent reply other threads:[~2008-08-19 11:42 UTC|newest]
Thread overview: 56+ 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 ` ehrhardt
2008-08-19 10:36 ` [PATCH 1/4] kvmppc: read device tree hypervisor node infrastructure ehrhardt
2008-08-19 10:36 ` ehrhardt
2008-08-19 11:52 ` [PATCH 1/4] kvmppc: read device tree hypervisor node Josh Boyer
2008-08-19 11:52 ` [PATCH 1/4] kvmppc: read device tree hypervisor node infrastructure Josh Boyer
2008-08-19 11:56 ` [PATCH 1/4] kvmppc: read device tree hypervisor node Josh Boyer
2008-08-19 11:56 ` [PATCH 1/4] kvmppc: read device tree hypervisor node infrastructure Josh Boyer
2008-08-19 10:36 ` [PATCH 2/4] kvmppc: add hypercall infrastructure - guest part ehrhardt
2008-08-19 10:36 ` ehrhardt
2008-08-19 11:28 ` Arnd Bergmann
2008-08-19 11:28 ` Arnd Bergmann
2008-08-20 12:41 ` Christian Ehrhardt
2008-08-20 12:41 ` Christian Ehrhardt
2008-08-21 22:25 ` Hollis Blanchard
2008-08-21 22:25 ` Hollis Blanchard
2008-08-22 10:38 ` Kumar Gala
2008-08-22 10:38 ` Kumar Gala
2008-08-22 14:00 ` Hollis Blanchard
2008-08-22 14:00 ` Hollis Blanchard
2008-08-19 10:36 ` [PATCH 3/4] kvmppc: magic page paravirtualization " ehrhardt
2008-08-19 10:36 ` ehrhardt
2008-08-20 2:29 ` Tony Breeds
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 10:36 ` ehrhardt
2008-08-19 11:42 ` Arnd Bergmann [this message]
2008-08-19 11:42 ` Arnd Bergmann
2008-08-20 12:53 ` Christian Ehrhardt
2008-08-20 12:53 ` Christian Ehrhardt
2008-08-20 18:30 ` [PATCH 4/4] kvmppc: convert wrteei to wrtee as kvm guest Hollis Blanchard
2008-08-20 18:30 ` [PATCH 4/4] kvmppc: convert wrteei to wrtee as kvm guest optimization Hollis Blanchard
2008-08-20 18:52 ` [PATCH 4/4] kvmppc: convert wrteei to wrtee as kvm guest Josh Boyer
2008-08-20 18:52 ` [PATCH 4/4] kvmppc: convert wrteei to wrtee as kvm guest optimization Josh Boyer
2008-08-20 19:06 ` [PATCH 4/4] kvmppc: convert wrteei to wrtee as kvm guest Hollis Blanchard
2008-08-20 19:06 ` [PATCH 4/4] kvmppc: convert wrteei to wrtee as kvm guest optimization Hollis Blanchard
2008-08-20 19:18 ` [PATCH 4/4] kvmppc: convert wrteei to wrtee as kvm guest Josh Boyer
2008-08-20 19:18 ` [PATCH 4/4] kvmppc: convert wrteei to wrtee as kvm guest optimization Josh Boyer
2008-08-21 13:31 ` Christian Ehrhardt
2008-08-21 13:31 ` Christian Ehrhardt
2008-08-21 13:41 ` Kumar Gala
2008-08-21 13:41 ` Kumar Gala
2008-08-21 14:13 ` Christian Ehrhardt
2008-08-21 14:13 ` Christian Ehrhardt
2008-08-21 14:21 ` Kumar Gala
2008-08-21 14:21 ` Kumar Gala
2008-08-21 16:16 ` Scott Wood
2008-08-21 16:16 ` Scott Wood
2008-08-22 8:08 ` Christian Ehrhardt
2008-08-22 8:08 ` Christian Ehrhardt
2008-08-22 8:17 ` Kumar Gala
2008-08-22 8:17 ` Kumar Gala
2008-08-22 13:56 ` Jimi Xenidis
2008-08-22 13:56 ` Jimi Xenidis
2008-08-22 15:49 ` Scott Wood
2008-08-22 15:49 ` Scott Wood
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