From: Wanpeng Li <wanpeng.li@linux.intel.com>
To: Andrew Honig <ahonig@google.com>
Cc: "Wu, Feng" <feng.wu@intel.com>,
Steve Rutherford <srutherford@google.com>,
Paolo Bonzini <pbonzini@redhat.com>,
"kvm@vger.kernel.org" <kvm@vger.kernel.org>
Subject: Re: [RFC PATCH 1/4] KVM: x86: Split the APIC from the rest of IRQCHIP.
Date: Fri, 15 May 2015 13:03:02 +0800 [thread overview]
Message-ID: <20150515050302.GA7255@kernel> (raw)
In-Reply-To: <CAKB9nXuzkeYZAiyTcvu=QgqN9TQB0kCr3-8CAvkREN-7Z=ieNw@mail.gmail.com>
On Thu, May 14, 2015 at 12:29:21PM -0700, Andrew Honig wrote:
>>
>> BTW, what is the purpose of this series. If I understand it correctly, you only want to
>> use the in-kernel lapic and leave the others (pic, ioapic) in userspace, what is the
>> benefit of it?
>
>The purpose is to achieve the security benefit of removing some of the
>interrupt handling into userspace, without incurring a significant
>performance penalty. If you move the entire IRQCHIP into userspace,
>we've seen perf impacts from 15-200% depending on the workload. With
>this patch series, we're seeing perf penalty <1% on our tests (TCP_RR
Why keep pic and ioapic in kernel space not get obvious benefit, what's
the bottleneck?
Regards,
Wanpeng Li
>latency, TCP throughput, and Disk I/O). See
>(https://lwn.net/Articles/619332/)
>
>>
>> Thanks,
>> Feng
>>
>>>
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next prev parent reply other threads:[~2015-05-15 5:20 UTC|newest]
Thread overview: 41+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-05-13 1:47 [RFC PATCH 1/4] KVM: x86: Split the APIC from the rest of IRQCHIP Steve Rutherford
2015-05-13 1:47 ` [RFC PATCH 2/4] KVM: x86: Add KVM exit for IOAPIC EOIs Steve Rutherford
2015-05-13 7:35 ` Paolo Bonzini
2015-05-13 22:18 ` Steve Rutherford
2015-05-24 16:46 ` Avi Kivity
2015-05-27 2:06 ` Steve Rutherford
2015-05-27 5:32 ` Avi Kivity
2015-05-28 21:58 ` Steve Rutherford
2015-05-13 1:47 ` [RFC PATCH 3/4] KVM: x86: Add EOI exit bitmap inference Steve Rutherford
2015-05-13 6:12 ` Jan Kiszka
2015-05-13 8:04 ` Paolo Bonzini
2015-05-13 8:10 ` Jan Kiszka
2015-05-13 9:24 ` Paolo Bonzini
2015-05-13 10:25 ` Jan Kiszka
2015-05-13 13:04 ` Paolo Bonzini
2015-05-13 13:19 ` Jan Kiszka
2015-05-13 22:21 ` Steve Rutherford
2015-05-15 2:38 ` Steve Rutherford
2015-05-13 7:51 ` Paolo Bonzini
2015-05-13 22:24 ` Steve Rutherford
2015-05-14 9:20 ` Paolo Bonzini
2015-05-14 15:23 ` Alex Williamson
2015-05-14 15:46 ` Paolo Bonzini
2015-05-14 16:04 ` Alex Williamson
2015-05-14 22:10 ` Steve Rutherford
2015-05-14 22:35 ` Alex Williamson
2015-05-14 23:21 ` Steve Rutherford
2015-05-13 1:47 ` [RFC PATCH 4/4] KVM: x86: Add support for local interrupt requests from userspace Steve Rutherford
2015-05-13 6:12 ` Jan Kiszka
2015-05-13 22:41 ` Steve Rutherford
2015-05-15 13:27 ` Jan Kiszka
2015-05-13 7:22 ` Paolo Bonzini
2015-05-13 23:13 ` Steve Rutherford
2015-05-13 7:57 ` [RFC PATCH 1/4] KVM: x86: Split the APIC from the rest of IRQCHIP Paolo Bonzini
2015-05-13 22:10 ` Steve Rutherford
2015-05-14 9:12 ` Wu, Feng
2015-05-14 19:29 ` Andrew Honig
2015-05-15 1:28 ` Wu, Feng
2015-05-15 5:03 ` Wanpeng Li [this message]
2015-05-15 18:10 ` Steve Rutherford
2015-05-18 2:11 ` Wanpeng Li
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