From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753498Ab0IPJ7K (ORCPT ); Thu, 16 Sep 2010 05:59:10 -0400 Received: from mx1.redhat.com ([209.132.183.28]:31246 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751532Ab0IPJ7J (ORCPT ); Thu, 16 Sep 2010 05:59:09 -0400 Date: Thu, 16 Sep 2010 11:53:10 +0200 From: "Michael S. Tsirkin" To: Avi Kivity Cc: Gleb Natapov , Marcelo Tosatti , kvm@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH RFC] kvm: enable irq injection from interrupt context Message-ID: <20100916095310.GG20864@redhat.com> References: <20100915185417.GA3924@redhat.com> <20100916090256.GU3008@redhat.com> <20100916091054.GA20864@redhat.com> <20100916092553.GV3008@redhat.com> <4C91E75B.6010704@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4C91E75B.6010704@redhat.com> User-Agent: Mutt/1.5.20 (2009-12-10) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Sep 16, 2010 at 11:46:03AM +0200, Avi Kivity wrote: > On 09/16/2010 11:25 AM, Gleb Natapov wrote: > >> > >> MSI only appeared in rhel6, older guests still use level interrupts. > >So they are already slow for other reasons. > > > > Exactly, for example they need to exit to userspace to ack the > interrupt. That's far slower than the workqueue. Well, this is not exactly comparable: you might get same irq asserted multiple times and only deasserted once. > -- > error compiling committee.c: too many arguments to function