From nobody Fri Oct 24 22:15:39 2025 Delivered-To: importer@patchew.org Received-SPF: pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) client-ip=208.118.235.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Authentication-Results: mx.zohomail.com; spf=pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org Return-Path: Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) by mx.zohomail.com with SMTPS id 1518690363279115.98016066295042; Thu, 15 Feb 2018 02:26:03 -0800 (PST) Received: from localhost ([::1]:60732 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1emGj0-0001Sa-QD for importer@patchew.org; Thu, 15 Feb 2018 05:25:10 -0500 Received: from eggs.gnu.org ([2001:4830:134:3::10]:50958) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1emGei-0006Cf-RG for qemu-devel@nongnu.org; Thu, 15 Feb 2018 05:20:49 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1emGee-0001xo-11 for qemu-devel@nongnu.org; Thu, 15 Feb 2018 05:20:44 -0500 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:43712 helo=mx0a-001b2d01.pphosted.com) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1emGed-0001xZ-SP for qemu-devel@nongnu.org; Thu, 15 Feb 2018 05:20:39 -0500 Received: from pps.filterd (m0098417.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.22/8.16.0.22) with SMTP id w1FAJXYh115002 for ; Thu, 15 Feb 2018 05:20:36 -0500 Received: from e06smtp14.uk.ibm.com (e06smtp14.uk.ibm.com [195.75.94.110]) by mx0a-001b2d01.pphosted.com with ESMTP id 2g53j6adjc-1 (version=TLSv1.2 cipher=AES256-SHA bits=256 verify=NOT) for ; Thu, 15 Feb 2018 05:20:36 -0500 Received: from localhost by e06smtp14.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! 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Violators will be prosecuted; Thu, 15 Feb 2018 10:20:31 -0000 Received: from d06av24.portsmouth.uk.ibm.com (d06av24.portsmouth.uk.ibm.com [9.149.105.60]) by b06cxnps3075.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id w1FAKUEh17760358; Thu, 15 Feb 2018 10:20:30 GMT Received: from d06av24.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 761924203F; Thu, 15 Feb 2018 10:13:16 +0000 (GMT) Received: from d06av24.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 1CD5942041; Thu, 15 Feb 2018 10:13:16 +0000 (GMT) Received: from bradbury.ibm.com (unknown [9.152.222.92]) by d06av24.portsmouth.uk.ibm.com (Postfix) with ESMTP; Thu, 15 Feb 2018 10:13:16 +0000 (GMT) From: Viktor Mihajlovski To: qemu-devel@nongnu.org Date: Thu, 15 Feb 2018 11:20:25 +0100 X-Mailer: git-send-email 1.9.1 In-Reply-To: <1518690027-31318-1-git-send-email-mihajlov@linux.vnet.ibm.com> References: <1518690027-31318-1-git-send-email-mihajlov@linux.vnet.ibm.com> X-TM-AS-GCONF: 00 x-cbid: 18021510-0016-0000-0000-00000523017C X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 18021510-0017-0000-0000-0000285FCEED Message-Id: <1518690027-31318-3-git-send-email-mihajlov@linux.vnet.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:, , definitions=2018-02-15_04:, , signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 suspectscore=3 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 impostorscore=0 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1709140000 definitions=main-1802150128 X-detected-operating-system: by eggs.gnu.org: GNU/Linux 3.x [generic] [fuzzy] X-Received-From: 148.163.158.5 Subject: [Qemu-devel] [PATCHv3 2/4] qmp: add query-cpus-fast X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: ehabkost@redhat.com, david@redhat.com, cohuck@redhat.com, armbru@redhat.com, agraf@suse.de, borntraeger@de.ibm.com, qemu-s390x@nongnu.org, pbonzini@redhat.com, dgilbert@redhat.com, rth@twiddle.net Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail: RSF_0 Z_629925259 SPT_0 Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" From: Luiz Capitulino The query-cpus command has an extremely serious side effect: it always interrupts all running vCPUs so that they can run ioctl calls. This can cause a huge performance degradation for some workloads. And most of the information retrieved by the ioctl calls are not even used by query-cpus. This commit introduces a replacement for query-cpus called query-cpus-fast, which has the following features: o Never interrupt vCPUs threads. query-cpus-fast only returns vCPU information maintained by QEMU itself, which should be sufficient for most management software needs o Drop "halted" field as it can not retrieved in a fast way on most architectures o Drop irrelevant fields such as "current", "pc" and "arch" o Rename some fields for better clarification & proper naming standard Signed-off-by: Luiz Capitulino Signed-off-by: Viktor Mihajlovski Reviewed-by: Cornelia Huck Acked-by: Dr. David Alan Gilbert Acked-by: Eric Blake --- cpus.c | 38 ++++++++++++++++++++++++++++ hmp-commands-info.hx | 14 +++++++++++ hmp.c | 14 +++++++++++ hmp.h | 1 + qapi-schema.json | 70 ++++++++++++++++++++++++++++++++++++++++++++++++= ++++ 5 files changed, 137 insertions(+) diff --git a/cpus.c b/cpus.c index 6006931..6df6660 100644 --- a/cpus.c +++ b/cpus.c @@ -2156,6 +2156,44 @@ CpuInfoList *qmp_query_cpus(Error **errp) return head; } =20 +/* + * fast means: we NEVER interrupt vCPU threads to retrieve + * information from KVM. + */ +CpuInfoFastList *qmp_query_cpus_fast(Error **errp) +{ + MachineState *ms =3D MACHINE(qdev_get_machine()); + MachineClass *mc =3D MACHINE_GET_CLASS(ms); + CpuInfoFastList *head =3D NULL, *cur_item =3D NULL; + CPUState *cpu; + + CPU_FOREACH(cpu) { + CpuInfoFastList *info =3D g_malloc0(sizeof(*info)); + info->value =3D g_malloc0(sizeof(*info->value)); + + info->value->cpu_index =3D cpu->cpu_index; + info->value->qom_path =3D object_get_canonical_path(OBJECT(cpu)); + info->value->thread_id =3D cpu->thread_id; + + info->value->has_props =3D !!mc->cpu_index_to_instance_props; + if (info->value->has_props) { + CpuInstanceProperties *props; + props =3D g_malloc0(sizeof(*props)); + *props =3D mc->cpu_index_to_instance_props(ms, cpu->cpu_index); + info->value->props =3D props; + } + + if (!cur_item) { + head =3D cur_item =3D info; + } else { + cur_item->next =3D info; + cur_item =3D info; + } + } + + return head; +} + void qmp_memsave(int64_t addr, int64_t size, const char *filename, bool has_cpu, int64_t cpu_index, Error **errp) { diff --git a/hmp-commands-info.hx b/hmp-commands-info.hx index ad590a4..16ac602 100644 --- a/hmp-commands-info.hx +++ b/hmp-commands-info.hx @@ -160,6 +160,20 @@ Show infos for each CPU. ETEXI =20 { + .name =3D "cpus_fast", + .args_type =3D "", + .params =3D "", + .help =3D "show information for each CPU without interruptin= g them", + .cmd =3D hmp_info_cpus_fast, + }, + +STEXI +@item info cpus_fast +@findex info cpus_fast +Show infos for each CPU without performance penalty. +ETEXI + + { .name =3D "history", .args_type =3D "", .params =3D "", diff --git a/hmp.c b/hmp.c index a6b94b7..0bd3b3a 100644 --- a/hmp.c +++ b/hmp.c @@ -410,6 +410,20 @@ void hmp_info_cpus(Monitor *mon, const QDict *qdict) qapi_free_CpuInfoList(cpu_list); } =20 +void hmp_info_cpus_fast(Monitor *mon, const QDict *qdict) +{ + CpuInfoFastList *head, *cpu; + + head =3D qmp_query_cpus_fast(NULL); + + for (cpu =3D head; cpu; cpu =3D cpu->next) { + monitor_printf(mon, " CPU #%" PRId64 ":", cpu->value->cpu_index); + monitor_printf(mon, " thread-id=3D%" PRId64 "\n", cpu->value->thre= ad_id); + } + + qapi_free_CpuInfoFastList(head); +} + static void print_block_info(Monitor *mon, BlockInfo *info, BlockDeviceInfo *inserted, bool verbose) { diff --git a/hmp.h b/hmp.h index 1143db4..93fb4e4 100644 --- a/hmp.h +++ b/hmp.h @@ -29,6 +29,7 @@ void hmp_info_migrate_capabilities(Monitor *mon, const QD= ict *qdict); void hmp_info_migrate_parameters(Monitor *mon, const QDict *qdict); void hmp_info_migrate_cache_size(Monitor *mon, const QDict *qdict); void hmp_info_cpus(Monitor *mon, const QDict *qdict); +void hmp_info_cpus_fast(Monitor *mon, const QDict *qdict); void hmp_info_block(Monitor *mon, const QDict *qdict); void hmp_info_blockstats(Monitor *mon, const QDict *qdict); void hmp_info_vnc(Monitor *mon, const QDict *qdict); diff --git a/qapi-schema.json b/qapi-schema.json index 94d560e..815f072 100644 --- a/qapi-schema.json +++ b/qapi-schema.json @@ -552,6 +552,12 @@ # # Returns a list of information about each virtual CPU. # +# This command causes vCPU threads to exit to userspace, which causes +# a small interruption to guest CPU execution. This will have a negative +# impact on realtime guests and other latency sensitive guest workloads. +# It is recommended to use @query-cpus-fast instead of this command to +# avoid the vCPU interruption. +# # Returns: a list of @CpuInfo for each virtual CPU # # Since: 0.14.0 @@ -585,6 +591,70 @@ { 'command': 'query-cpus', 'returns': ['CpuInfo'] } =20 ## +# @CpuInfoFast: +# +# Information about a virtual CPU +# +# @cpu-index: index of the virtual CPU +# +# @qom-path: path to the CPU object in the QOM tree +# +# @thread-id: ID of the underlying host thread +# +# @props: properties describing to which node/socket/core/thread +# virtual CPU belongs to, provided if supported by board +# +# Since: 2.12 +# +## +{ 'struct': 'CpuInfoFast', + 'data': {'cpu-index': 'int', 'qom-path': 'str', + 'thread-id': 'int', '*props': 'CpuInstanceProperties' } } + +## +# @query-cpus-fast: +# +# Returns information about all virtual CPUs. This command does not +# incur a performance penalty and should be used in production +# instead of query-cpus. +# +# Returns: list of @CpuInfoFast +# +# Notes: The CPU architecture name is not returned by query-cpus-fast. +# Use query-target to retrieve that information. +# +# Since: 2.12 +# +# Example: +# +# -> { "execute": "query-cpus-fast" } +# <- { "return": [ +# { +# "thread-id": 25627, +# "props": { +# "core-id": 0, +# "thread-id": 0, +# "socket-id": 0 +# }, +# "qom-path": "/machine/unattached/device[0]", +# "cpu-index": 0 +# }, +# { +# "thread-id": 25628, +# "props": { +# "core-id": 0, +# "thread-id": 0, +# "socket-id": 1 +# }, +# "qom-path": "/machine/unattached/device[2]", +# "cpu-index": 1 +# } +# ] +# } +## +{ 'command': 'query-cpus-fast', 'returns': [ 'CpuInfoFast' ] } + +## # @IOThreadInfo: # # Information about an iothread --=20 1.9.1