From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: [PATCH 0/8] use jump labels to streamline common APIC configuration Date: Tue, 14 Aug 2012 19:21:10 +0300 Message-ID: <502A7AF6.7010609@redhat.com> References: <1344171513-4659-1-git-send-email-gleb@redhat.com> <501E760E.9050109@redhat.com> <20120805133549.GL27579@redhat.com> <501E7839.2030008@redhat.com> <20120805134842.GM27579@redhat.com> <501E7C85.70001@redhat.com> <20120805140305.GN27579@redhat.com> <502A5A16.6040506@siemens.com> <20120814140348.GM11194@redhat.com> <502A5E96.6090908@siemens.com> <20120814143758.GP11194@redhat.com> <502A67AC.3000209@siemens.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: Gleb Natapov , "kvm@vger.kernel.org" , "mtosatti@redhat.com" To: Jan Kiszka Return-path: Received: from mx1.redhat.com ([209.132.183.28]:2068 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752894Ab2HNQVO (ORCPT ); Tue, 14 Aug 2012 12:21:14 -0400 In-Reply-To: <502A67AC.3000209@siemens.com> Sender: kvm-owner@vger.kernel.org List-ID: On 08/14/2012 05:58 PM, Jan Kiszka wrote: >>> >>> And regarding how common they are: Do standard OSes trigger any >>> jump-label optimized switch during at least their boot-up? I thought so. >>> In that case, if you co-locate RT and standard OSes on a shared host, >>> you would have a conflict. >>> >> Yes, during boot up it happens. But it is rate limited to happen not >> more than once per second. But I genuinely curious does RT guest have >> any RT guaranties from QEMU/kvm combination today (with of without >> jump-labels)? > > Yes, when avoiding userspace exits. If you have a customized RTOS guest > or are lucky with some existing one, that works pretty well for periodic > processing in the 1 ms range. I'd have expected better. For more formal support, we need some ioctl() to pre-populate mappings, or perhaps extend mmu notifiers to report mlock un munlock operations and take them as a hint to premap. -- error compiling committee.c: too many arguments to function