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From: Jan Kiszka <jan.kiszka@siemens.com>
To: Avi Kivity <avi@redhat.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>,
	qemu-devel <qemu-devel@nongnu.org>, kvm <kvm@vger.kernel.org>
Subject: Re: qemu-kvm upstreaming: Do we want -kvm-shadow-memory semantics?
Date: Wed, 25 Jan 2012 13:10:38 +0100	[thread overview]
Message-ID: <4F1FF13E.5090405@siemens.com> (raw)
In-Reply-To: <4F1FEFCA.2060907@redhat.com>

On 2012-01-25 13:04, Avi Kivity wrote:
> On 01/25/2012 01:57 PM, Jan Kiszka wrote:
>>>
>>> -kvm-shadow-memory is becoming less meaningful for ordinary workloads
>>> since everything uses TDP these days.  It's still meaningful for testing
>>> (forcing aggressive cache replacement), or perhaps nested virtualization.
>>
>> So, is it used for testing in fact? 
> 
> It is not, but it should be.  There's an extra_params option in
> autotest, I'll start using it to stress the mmu some more, even though
> it's going to slow things down for me.

OK.

> 
>> Would a machine option
>> "kvm_shadow_memory=n" be desirable?
> 
> Not sure, this is a host option, not a guest option.  Machine options
> should be guest-visible.

machine options are not guest visible. Basically, this options falls
into the same category as kernel_irqchip.

Do we have alternatives? A top-level command line options is surely none.

Jan

-- 
Siemens AG, Corporate Technology, CT T DE IT 1
Corporate Competence Center Embedded Linux

WARNING: multiple messages have this Message-ID (diff)
From: Jan Kiszka <jan.kiszka@siemens.com>
To: Avi Kivity <avi@redhat.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>,
	qemu-devel <qemu-devel@nongnu.org>, kvm <kvm@vger.kernel.org>
Subject: Re: [Qemu-devel] qemu-kvm upstreaming: Do we want -kvm-shadow-memory semantics?
Date: Wed, 25 Jan 2012 13:10:38 +0100	[thread overview]
Message-ID: <4F1FF13E.5090405@siemens.com> (raw)
In-Reply-To: <4F1FEFCA.2060907@redhat.com>

On 2012-01-25 13:04, Avi Kivity wrote:
> On 01/25/2012 01:57 PM, Jan Kiszka wrote:
>>>
>>> -kvm-shadow-memory is becoming less meaningful for ordinary workloads
>>> since everything uses TDP these days.  It's still meaningful for testing
>>> (forcing aggressive cache replacement), or perhaps nested virtualization.
>>
>> So, is it used for testing in fact? 
> 
> It is not, but it should be.  There's an extra_params option in
> autotest, I'll start using it to stress the mmu some more, even though
> it's going to slow things down for me.

OK.

> 
>> Would a machine option
>> "kvm_shadow_memory=n" be desirable?
> 
> Not sure, this is a host option, not a guest option.  Machine options
> should be guest-visible.

machine options are not guest visible. Basically, this options falls
into the same category as kernel_irqchip.

Do we have alternatives? A top-level command line options is surely none.

Jan

-- 
Siemens AG, Corporate Technology, CT T DE IT 1
Corporate Competence Center Embedded Linux

  reply	other threads:[~2012-01-25 12:10 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-01-19 12:46 qemu-kvm upstreaming: Do we want -kvm-shadow-memory semantics? Jan Kiszka
2012-01-19 12:46 ` [Qemu-devel] " Jan Kiszka
2012-01-19 13:24 ` Alexander Graf
2012-01-19 13:24   ` Alexander Graf
2012-01-19 13:30   ` Jan Kiszka
2012-01-19 13:30     ` Jan Kiszka
2012-01-19 13:42     ` Alexander Graf
2012-01-19 13:42       ` Alexander Graf
2012-01-19 17:28 ` Marcelo Tosatti
2012-01-19 17:28   ` [Qemu-devel] " Marcelo Tosatti
2012-01-19 17:39   ` Jan Kiszka
2012-01-19 17:39     ` [Qemu-devel] " Jan Kiszka
2012-01-25 11:38     ` Avi Kivity
2012-01-25 11:38       ` [Qemu-devel] " Avi Kivity
2012-01-25 11:57       ` Jan Kiszka
2012-01-25 11:57         ` [Qemu-devel] " Jan Kiszka
2012-01-25 12:04         ` Avi Kivity
2012-01-25 12:04           ` [Qemu-devel] " Avi Kivity
2012-01-25 12:10           ` Jan Kiszka [this message]
2012-01-25 12:10             ` Jan Kiszka
2012-01-25 12:15             ` Avi Kivity
2012-01-25 12:26               ` Jan Kiszka
2012-01-25 12:33                 ` Avi Kivity

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