From mboxrd@z Thu Jan 1 00:00:00 1970 From: Matt Mackall Subject: Re: [PATCH 2/9] Sched clock paravirt op fix.patch Date: Fri, 16 Mar 2007 16:29:48 -0500 Message-ID: <20070316212948.GH10459@waste.org> References: <200703020254.l222sOaM009656@zach-dev.vmware.com> <20070313140129.GB92373@muc.de> <45F6C2A3.4040305@goop.org> <20070313160709.GH10574@sequoia.sous-sol.org> <20070313161656.GA12128@muc.de> <45F6D361.8080106@redhat.com> <20070313205628.GB46469@muc.de> <45F71207.8050605@goop.org> Mime-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Return-path: Content-Disposition: inline In-Reply-To: <45F71207.8050605@goop.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: virtualization-bounces@lists.linux-foundation.org Errors-To: virtualization-bounces@lists.linux-foundation.org To: Jeremy Fitzhardinge Cc: Chris Wright , Andi Kleen , Andrew Morton , Daniel Walker , Virtualization Mailing List , Linus Torvalds , Linux Kernel Mailing List List-Id: virtualization@lists.linuxfoundation.org On Tue, Mar 13, 2007 at 02:05:11PM -0700, Jeremy Fitzhardinge wrote: > Andi Kleen wrote: > > It depends -- under heavy network load you can spend a long time > > just processing interrupts. > = > Well, in that case you probably don't want to charge them to the process > which happens to be running at the time. It's actually a good first-order approximation of the right thing to do, as it will generally correlate with the userspace process servicing that network load. If not (for instance, with routing loads), then you'd basically expect the charge to get spread around evenly in proportion to an application's CPU usage. The -rt kernel pushes most of the interrupt work off to threads, which of course follow the same scheduling and accounting rules as everything other thread. -- = Mathematics is the supreme nostalgia of our time.