From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf0-x243.google.com (mail-pf0-x243.google.com [IPv6:2607:f8b0:400e:c00::243]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 3swHhW1xXQzDt2K for ; Fri, 14 Oct 2016 17:27:39 +1100 (AEDT) Received: by mail-pf0-x243.google.com with SMTP id 128so6575339pfz.1 for ; Thu, 13 Oct 2016 23:27:39 -0700 (PDT) Date: Fri, 14 Oct 2016 17:27:30 +1100 From: Nicholas Piggin To: Suraj Jitindar Singh Cc: pbonzini@redhat.com, rkrcmar@redhat.com, agraf@suse.com, corbet@lwn.net, kvm@vger.kernel.org, linux-doc@vger.kernel.org, kvm-ppc@vger.kernel.org, paulus@samba.org, linuxppc-dev@lists.ozlabs.org, sam.bobroff@au1.ibm.com Subject: Re: [PATCH 0/6] kvm: powerpc halt polling updates Message-ID: <20161014172730.127ed3fb@roar.ozlabs.ibm.com> In-Reply-To: <1476406404-32752-1-git-send-email-sjitindarsingh@gmail.com> References: <1476406404-32752-1-git-send-email-sjitindarsingh@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Fri, 14 Oct 2016 11:53:18 +1100 Suraj Jitindar Singh wrote: > This patch series makes some updates and bug fixes to the powerpc kvm-hv > halt polling code. > > The first two patches are concerned with exporting the generic kvm module > parameter variables and accessing these from the powerpc specific code. > > The third patch fixes a bug where changing the global max halt polling > interval module parameter can sometimes have no effect. > > The fourth patch decreases the default global max halt polling interval > to something more sensible. > > The fifth patch contains generic fixups with no functional effect. > > The last patch adds halt polling documentation. I want to enable polling idle in Linux for SPLPAR/KVM as we do for dedicated mode. Essentially the guest OS will spin for a small time before ceding. There will be a lot of interaction between this and halt polling. I think guest polling may still be worthwhile if you have halt polling in the host, although it might be less effective. We should set up some performance testing with various guest/host parameters and see what works best. What have you been testing with so far? Thanks, Nick