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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 63723C43334 for ; Mon, 18 Jul 2022 09:34:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234184AbiGRJeR (ORCPT ); Mon, 18 Jul 2022 05:34:17 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57756 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234044AbiGRJeQ (ORCPT ); Mon, 18 Jul 2022 05:34:16 -0400 Received: from mx0b-001b2d01.pphosted.com (mx0b-001b2d01.pphosted.com [148.163.158.5]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 53EBB1057C; Mon, 18 Jul 2022 02:34:14 -0700 (PDT) Received: from pps.filterd (m0098421.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.17.1.5/8.17.1.5) with ESMTP id 26I9OJwC013534; Mon, 18 Jul 2022 09:34:13 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ibm.com; h=message-id : date : mime-version : subject : to : cc : references : from : in-reply-to : content-type : content-transfer-encoding; s=pp1; bh=CLtnuMZn0IaIeUfNRVokFsAu9Vmt+6KkmjlqpPstuWE=; b=PgWIVighlvRiymHGqWnzV5Rv+2l2kHDAaNYvDHRaOIcV1SSKTaxzvfQsSZ75zmBaOQHc uIwq+0WZRVyKHdP+VxlL6lo3gRUZXXU/vFshDRcbOIBxFNbtTGC6f5iLiB55dDEpJHSl jT5MQ8HOGGImR6ZxkqT8YcfQlcnyMu/rthXQ2WhH7FQodZH0G9p29v52F6sp1MZlcQnZ IvShXHJyo/T7QwTu+J/6TqJ+AodoAEjfno0mWmBUGVSW9f/GDsx1lNbG2Y8qZEx0J694 bizSCsRpRouMidnlQnf0CuWtWZYI3bQ1lSDGCYB4ac43jy3xPNln9TAcZ+DNDBm+aotN 9A== Received: from pps.reinject (localhost [127.0.0.1]) by mx0a-001b2d01.pphosted.com (PPS) with ESMTPS id 3hd4uyr810-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Mon, 18 Jul 2022 09:34:13 +0000 Received: from m0098421.ppops.net (m0098421.ppops.net [127.0.0.1]) by pps.reinject (8.17.1.5/8.17.1.5) with ESMTP id 26I9QJOF025620; Mon, 18 Jul 2022 09:34:13 GMT Received: from ppma03ams.nl.ibm.com (62.31.33a9.ip4.static.sl-reverse.com [169.51.49.98]) by mx0a-001b2d01.pphosted.com (PPS) with ESMTPS id 3hd4uyr804-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Mon, 18 Jul 2022 09:34:12 +0000 Received: from pps.filterd (ppma03ams.nl.ibm.com [127.0.0.1]) by ppma03ams.nl.ibm.com (8.16.1.2/8.16.1.2) with SMTP id 26I9KRsm017554; Mon, 18 Jul 2022 09:34:11 GMT Received: from b06cxnps4076.portsmouth.uk.ibm.com (d06relay13.portsmouth.uk.ibm.com [9.149.109.198]) by ppma03ams.nl.ibm.com with ESMTP id 3hbmy8tb70-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Mon, 18 Jul 2022 09:34:11 +0000 Received: from d06av21.portsmouth.uk.ibm.com (d06av21.portsmouth.uk.ibm.com [9.149.105.232]) by b06cxnps4076.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 26I9Y8Cm11665912 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Mon, 18 Jul 2022 09:34:09 GMT Received: from d06av21.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id D0CCE5204E; Mon, 18 Jul 2022 09:34:08 +0000 (GMT) Received: from [9.171.53.146] (unknown [9.171.53.146]) by d06av21.portsmouth.uk.ibm.com (Postfix) with ESMTP id 918825204F; Mon, 18 Jul 2022 09:34:08 +0000 (GMT) Message-ID: <90e2ebcd-f411-8d44-bf44-5df80fb59b51@linux.ibm.com> Date: Mon, 18 Jul 2022 11:34:08 +0200 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.10.0 Subject: Re: [PATCH] kvm: stats: tell userspace which values are boolean Content-Language: en-US To: Paolo Bonzini , linux-kernel@vger.kernel.org, kvm@vger.kernel.org Cc: Amneesh Singh References: <20220714120330.1410308-1-pbonzini@redhat.com> From: Janis Schoetterl-Glausch In-Reply-To: <20220714120330.1410308-1-pbonzini@redhat.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-TM-AS-GCONF: 00 X-Proofpoint-ORIG-GUID: ShPBIaQuF6uMl3ehzNI5XhMv0L9pGx99 X-Proofpoint-GUID: be1TbGoNuk6AVmzsBfJfTR1nMuPj0o6m X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.205,Aquarius:18.0.883,Hydra:6.0.517,FMLib:17.11.122.1 definitions=2022-07-18_08,2022-07-15_01,2022-06-22_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 phishscore=0 impostorscore=0 malwarescore=0 bulkscore=0 mlxlogscore=999 lowpriorityscore=0 spamscore=0 clxscore=1011 adultscore=0 suspectscore=0 priorityscore=1501 mlxscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2206140000 definitions=main-2207180038 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 7/14/22 14:03, Paolo Bonzini wrote: > Some of the statistics values exported by KVM are always only 0 or 1. > It can be useful to export this fact to userspace so that it can track > them specially (for example by polling the value every now and then to > compute a % of time spent in a specific state). > > Therefore, add "boolean value" as a new "unit". While it is not exactly > a unit, it walks and quacks like one. In particular, using the type > would be wrong because boolean values could be instantaneous or peak > values (e.g. "is the rmap allocated?") or even two-bucket histograms > (e.g. "number of posted vs. non-posted interrupt injections"). > > Suggested-by: Amneesh Singh > Signed-off-by: Paolo Bonzini > --- > Documentation/virt/kvm/api.rst | 6 ++++++ > arch/x86/kvm/x86.c | 2 +- > include/linux/kvm_host.h | 11 ++++++++++- > include/uapi/linux/kvm.h | 1 + > 4 files changed, 18 insertions(+), 2 deletions(-) > > diff --git a/Documentation/virt/kvm/api.rst b/Documentation/virt/kvm/api.rst > index 11e00a46c610..48bf6e49a7de 100644 > --- a/Documentation/virt/kvm/api.rst > +++ b/Documentation/virt/kvm/api.rst > @@ -5657,6 +5657,7 @@ by a string of size ``name_size``. > #define KVM_STATS_UNIT_BYTES (0x1 << KVM_STATS_UNIT_SHIFT) > #define KVM_STATS_UNIT_SECONDS (0x2 << KVM_STATS_UNIT_SHIFT) > #define KVM_STATS_UNIT_CYCLES (0x3 << KVM_STATS_UNIT_SHIFT) > + #define KVM_STATS_UNIT_BOOLEAN (0x4 << KVM_STATS_UNIT_SHIFT) > #define KVM_STATS_UNIT_MAX KVM_STATS_UNIT_CYCLES > > #define KVM_STATS_BASE_SHIFT 8 [...] > diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h > index 5088bd9f1922..811897dadcae 100644 > --- a/include/uapi/linux/kvm.h > +++ b/include/uapi/linux/kvm.h > @@ -2083,6 +2083,7 @@ struct kvm_stats_header { > #define KVM_STATS_UNIT_BYTES (0x1 << KVM_STATS_UNIT_SHIFT) > #define KVM_STATS_UNIT_SECONDS (0x2 << KVM_STATS_UNIT_SHIFT) > #define KVM_STATS_UNIT_CYCLES (0x3 << KVM_STATS_UNIT_SHIFT) > +#define KVM_STATS_UNIT_BOOLEAN (0x4 << KVM_STATS_UNIT_SHIFT) > #define KVM_STATS_UNIT_MAX KVM_STATS_UNIT_CYCLES Shouldn't KVM_STATS_UNIT_MAX be KVM_STATS_UNIT_BOOLEAN then? The selftest has: TEST_ASSERT((pdesc->flags & KVM_STATS_UNIT_MASK) <= KVM_STATS_UNIT_MAX, "Unknown KVM stats unit"); > > #define KVM_STATS_BASE_SHIFT 8