Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754027AbbBJTal (ORCPT ); Tue, 10 Feb 2015 14:30:41 -0500 Received: from mx1.redhat.com ([209.132.183.28]:59835 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753362AbbBJTak (ORCPT ); Tue, 10 Feb 2015 14:30:40 -0500 Date: Tue, 10 Feb 2015 17:30:18 -0200 From: Marcelo Tosatti To: Paolo Bonzini Cc: linux-kernel@vger.kernel.org, kvm@vger.kernel.org, riel@redhat.com, rkrcmar@redhat.com, dmatlack@google.com Subject: Re: [PATCH 2/2] KVM: x86: optimize delivery of TSC deadline timer interrupt Message-ID: <20150210193018.GA32006@amt.cnet> References: <1423225019-11001-1-git-send-email-pbonzini@redhat.com> <1423225019-11001-3-git-send-email-pbonzini@redhat.com> <20150206205137.GA27561@amt.cnet> <54D67685.5050205@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <54D67685.5050205@redhat.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 641 Lines: 19 On Sat, Feb 07, 2015 at 09:33:09PM +0100, Paolo Bonzini wrote: > > Can remove another 300 cycles from do_div when programming LAPIC > > tscdeadline timer. > > Do you mean using something like lib/reciprocal_div.c? Yes. > Good idea, > though that's not latency, it's just being slow. :) It adds to latency, yes (the guest will reprogram the APIC timer before resuming userspace execution). -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/