> -----Original Message----- > From: Andrew Honig [mailto:aho...@google.com] > Sent: Friday, May 15, 2015 3:29 AM > To: Wu, Feng > Cc: Steve Rutherford; Paolo Bonzini; kvm@vger.kernel.org > Subject: Re: [RFC PATCH 1/4] KVM: x86: Split the APIC from the rest of > IRQCHIP. > > > > > 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 > latency, TCP throughput, and Disk I/O). See > (https://lwn.net/Articles/619332/)
Good to know this, thanks for the sharing! Thanks, Feng > > > > > Thanks, > > Feng > > > >>
