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From: Tomoki Sekiyama <tomoki.sekiyama.qu@hitachi.com>
To: avi@redhat.com
Cc: jan.kiszka@siemens.com, kvm@vger.kernel.org,
	linux-kernel@vger.kernel.org, x86@kernel.org,
	yrl.pp-manager.tt@hitachi.com
Subject: Re: [RFC PATCH 00/18] KVM: x86: CPU isolation and direct interrupts handling by guests
Date: Fri, 06 Jul 2012 19:33:00 +0900	[thread overview]
Message-ID: <4FF6BEDC.8040207@hitachi.com> (raw)
In-Reply-To: <4FEDC22F.9070406@redhat.com>

Hi,

On 2012/06/29 23:56, Avi Kivity wrote:
>> On 2012/06/29 2:34, Avi Kivity wrote:
>>> On 06/28/2012 08:26 PM, Jan Kiszka wrote:
>>>>> This is both impressive and scary.  What is the target scenario here?
>>>>> Partitioning?  I don't see this working for generic consolidation.
>>>>
>>>> From my POV, partitioning - including hard realtime partitions - would
>>>> provide some use cases.
>>
>> Exactly this is for partitioning that requires bare-metal performance
>> with low latency and realtime.
>
> It's hard for me to evaluate how large that segment is.  Since the
> patchset is so intrusive, it needs a large potential user set to
> justify, or a large reduction in complexity, or both.

Low latency or realtime is often required on high-end systems
like trading, automated control, HPC and so on, or for multimedias.
Those who want to run MRG as a guest, or to fully utilize high-speed
NIC are also worth using this. And not all of such applications does
not use up every CPU, so partitioning is becoming reasonable as a
number of cores in a server is increasing.
Anyway, I will try to make the patch as simple as possible.

>>  I think it is also useful for workload
>> like HPC with MPI, that is CPU intensive and that needs low latency.
> 
> I keep hearing about people virtualizing these types of workloads, but I
> haven't yet understood why.

One reason is ease of deployment of applications to nodes.
Especially in IaaS environment like Amazon EC2 Cluster Compute Instances,
virtualization is often introduced as a simple way to move applications
around flexibly among nodes shared by many users.

Thanks,
-- 
Tomoki Sekiyama <tomoki.sekiyama.qu@hitachi.com>
Linux Technology Center
Hitachi, Ltd., Yokohama Research Laboratory


  reply	other threads:[~2012-07-06 10:32 UTC|newest]

Thread overview: 33+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-06-28  6:07 [RFC PATCH 00/18] KVM: x86: CPU isolation and direct interrupts handling by guests Tomoki Sekiyama
2012-06-28  6:07 ` [RFC PATCH 01/18] x86: Split memory hotplug function from cpu_up() as cpu_memory_up() Tomoki Sekiyama
2012-06-28  6:07 ` [RFC PATCH 02/18] x86: Add a facility to use offlined CPUs as slave CPUs Tomoki Sekiyama
2012-06-28  6:07 ` [RFC PATCH 03/18] x86: Support hrtimer on " Tomoki Sekiyama
2012-06-28  6:07 ` [RFC PATCH 04/18] KVM: Replace local_irq_disable/enable with local_irq_save/restore Tomoki Sekiyama
2012-06-28  6:07 ` [RFC PATCH 05/18] KVM: Enable/Disable virtualization on slave CPUs are activated/dying Tomoki Sekiyama
2012-06-28  6:07 ` [RFC PATCH 06/18] KVM: Add facility to run guests on slave CPUs Tomoki Sekiyama
2012-06-28 17:02   ` Avi Kivity
2012-06-29  9:26     ` Tomoki Sekiyama
2012-06-28  6:07 ` [RFC PATCH 07/18] KVM: handle page faults occured in slave CPUs on online CPUs Tomoki Sekiyama
2012-06-28  6:08 ` [RFC PATCH 08/18] KVM: Add KVM_GET_SLAVE_CPU and KVM_SET_SLAVE_CPU to vCPU ioctl Tomoki Sekiyama
2012-06-28  6:08 ` [RFC PATCH 09/18] KVM: Go back to online CPU on VM exit by external interrupt Tomoki Sekiyama
2012-06-28  6:08 ` [RFC PATCH 10/18] KVM: proxy slab operations for slave CPUs on online CPUs Tomoki Sekiyama
2012-06-28  6:08 ` [RFC PATCH 11/18] KVM: no exiting from guest when slave CPU halted Tomoki Sekiyama
2012-06-28  6:08 ` [RFC PATCH 12/18] x86/apic: Enable external interrupt routing to slave CPUs Tomoki Sekiyama
2012-06-28  6:08 ` [RFC PATCH 13/18] x86/apic: IRQ vector remapping on slave for " Tomoki Sekiyama
2012-06-28  6:08 ` [RFC PATCH 14/18] KVM: Directly handle interrupts by guests without VM EXIT on " Tomoki Sekiyama
2012-06-28  6:08 ` [RFC PATCH 15/18] KVM: vmx: Add definitions PIN_BASED_PREEMPTION_TIMER Tomoki Sekiyama
2012-06-28  6:08 ` [RFC PATCH 16/18] KVM: add kvm_arch_vcpu_prevent_run to prevent VM ENTER when NMI is received Tomoki Sekiyama
2012-06-28 16:48   ` Avi Kivity
2012-06-29  9:26     ` Tomoki Sekiyama
2012-06-28  6:08 ` [RFC PATCH 17/18] KVM: route assigned devices' MSI/MSI-X directly to guests on slave CPUs Tomoki Sekiyama
2012-06-28  6:08 ` [RFC PATCH 18/18] x86: request TLB flush to slave CPU using NMI Tomoki Sekiyama
2012-06-28 16:38   ` Avi Kivity
2012-06-29  9:26     ` Tomoki Sekiyama
2012-06-28 16:58 ` [RFC PATCH 00/18] KVM: x86: CPU isolation and direct interrupts handling by guests Avi Kivity
2012-06-28 17:26   ` Jan Kiszka
2012-06-28 17:34     ` Avi Kivity
2012-06-29  9:25       ` Tomoki Sekiyama
2012-06-29 14:56         ` Avi Kivity
2012-07-06 10:33           ` Tomoki Sekiyama [this message]
2012-07-12  9:04             ` Avi Kivity
2012-07-04  9:33 ` Tomoki Sekiyama

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