From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alex Williamson Subject: Re: [PATCHv4 0/2] kvm: direct msix injection Date: Tue, 27 Nov 2012 21:34:57 -0700 Message-ID: <1354077297.1809.189.camel@bling.home> References: <20121121192635.GA9268@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Cc: kvm@vger.kernel.org, Jan Kiszka To: "Michael S. Tsirkin" Return-path: Received: from mx1.redhat.com ([209.132.183.28]:17676 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752549Ab2K1Ee7 (ORCPT ); Tue, 27 Nov 2012 23:34:59 -0500 In-Reply-To: <20121121192635.GA9268@redhat.com> Sender: kvm-owner@vger.kernel.org List-ID: On Wed, 2012-11-21 at 21:26 +0200, Michael S. Tsirkin wrote: > On Wed, Oct 17, 2012 at 06:05:53PM +0200, Michael S. Tsirkin wrote: > > We can deliver certain interrupts, notably MSIX, > > from atomic context. > > Here's an untested patch to do this (compiled only). > > > > Changes from v2: > > Don't inject broadcast interrupts directly > > Changes from v1: > > Tried to address comments from v1, except unifying > > with kvm_set_irq: passing flags to it looks too ugly. > > Added a comment. > > > > Jan, you said you can test this? > > I have tested this with some networking workloads > and this patchset seems to work fine. > My setup isn't a good fit for benchmarking device > assignment though. > Alex, could you pls verifyu that this solves the > latency issue that you sometimes observe? > With this patchset device assignment latency should be > as fast as vfio. Yep, that seems to cover the gap. My environment is too noisy to declare an absolute winner, but pci-assign and vfio-pci are now very, very similar under netperf TCP_RR with these patches. Thanks, Alex