From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 11D9FC04E87 for ; Wed, 15 May 2019 11:34:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id DA1932089E for ; Wed, 15 May 2019 11:34:14 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2387416AbfEOLeN (ORCPT ); Wed, 15 May 2019 07:34:13 -0400 Received: from mx1.redhat.com ([209.132.183.28]:53604 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2387411AbfEOLeM (ORCPT ); Wed, 15 May 2019 07:34:12 -0400 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 4730381E1A; Wed, 15 May 2019 11:34:12 +0000 (UTC) Received: from gondolin (dhcp-192-222.str.redhat.com [10.33.192.222]) by smtp.corp.redhat.com (Postfix) with ESMTP id 8DF6E60CC0; Wed, 15 May 2019 11:34:08 +0000 (UTC) Date: Wed, 15 May 2019 13:34:06 +0200 From: Cornelia Huck To: Christian Borntraeger Cc: Janosch Frank , KVM , David Hildenbrand , Paolo Bonzini , Radim =?UTF-8?B?S3LEjW3DocWZ?= , Collin Walling , "Jason J . Herne" Subject: Re: [PATCH] KVM: s390: change default halt poll to 50000 Message-ID: <20190515133406.7b3ea902.cohuck@redhat.com> In-Reply-To: <20190515082324.112755-1-borntraeger@de.ibm.com> References: <20190515082324.112755-1-borntraeger@de.ibm.com> Organization: Red Hat GmbH MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.25]); Wed, 15 May 2019 11:34:12 +0000 (UTC) Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org On Wed, 15 May 2019 10:23:24 +0200 Christian Borntraeger wrote: > older performance measurements indicated that 50000 vs 80000 reduces cpu > consumption while still providing the benefit of halt polling. We had > this change in the IBM KVM product, but it got lost so it never went > upstream. Recent re-measurement indicate that 50k is still better than > 80k. > > Signed-off-by: Christian Borntraeger > --- > arch/s390/include/asm/kvm_host.h | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/arch/s390/include/asm/kvm_host.h b/arch/s390/include/asm/kvm_host.h > index dbe254847e0d..cb63cc7bbf06 100644 > --- a/arch/s390/include/asm/kvm_host.h > +++ b/arch/s390/include/asm/kvm_host.h > @@ -36,7 +36,7 @@ > */ > #define KVM_NR_IRQCHIPS 1 > #define KVM_IRQCHIP_NUM_PINS 4096 > -#define KVM_HALT_POLL_NS_DEFAULT 80000 > +#define KVM_HALT_POLL_NS_DEFAULT 50000 > > /* s390-specific vcpu->requests bit members */ > #define KVM_REQ_ENABLE_IBS KVM_ARCH_REQ(0) I trust your tests :) Acked-by: Cornelia Huck