From patchwork Fri Feb 16 16:08:38 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Viktor Mihajlovski X-Patchwork-Id: 10225027 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id B8E56602CB for ; Fri, 16 Feb 2018 16:10:21 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id A55F4295DA for ; Fri, 16 Feb 2018 16:10:21 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 972EA29593; Fri, 16 Feb 2018 16:10:21 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.9 required=2.0 tests=BAYES_00,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 09B7729593 for ; Fri, 16 Feb 2018 16:10:21 +0000 (UTC) Received: from localhost ([::1]:35952 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1emiaa-00023R-91 for patchwork-qemu-devel@patchwork.kernel.org; Fri, 16 Feb 2018 11:10:20 -0500 Received: from eggs.gnu.org ([2001:4830:134:3::10]:45028) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1emiZD-0000r8-Dd for qemu-devel@nongnu.org; Fri, 16 Feb 2018 11:08:57 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1emiZC-00007Q-0d for qemu-devel@nongnu.org; Fri, 16 Feb 2018 11:08:55 -0500 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:52868 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 1emiZB-000074-SS for qemu-devel@nongnu.org; Fri, 16 Feb 2018 11:08:53 -0500 Received: from pps.filterd (m0098420.ppops.net [127.0.0.1]) by mx0b-001b2d01.pphosted.com (8.16.0.22/8.16.0.22) with SMTP id w1GG75U0075825 for ; Fri, 16 Feb 2018 11:08:51 -0500 Received: from e06smtp15.uk.ibm.com (e06smtp15.uk.ibm.com [195.75.94.111]) by mx0b-001b2d01.pphosted.com with ESMTP id 2g5yuc7kxb-1 (version=TLSv1.2 cipher=AES256-SHA bits=256 verify=NOT) for ; Fri, 16 Feb 2018 11:08:50 -0500 Received: from localhost by e06smtp15.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! 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Violators will be prosecuted; Fri, 16 Feb 2018 16:08:45 -0000 Received: from d06av23.portsmouth.uk.ibm.com (d06av23.portsmouth.uk.ibm.com [9.149.105.59]) by b06cxnps4076.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id w1GG8jwZ47710266; Fri, 16 Feb 2018 16:08:45 GMT Received: from d06av23.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 9FFCCA4055; Fri, 16 Feb 2018 16:02:01 +0000 (GMT) Received: from d06av23.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 4D461A4040; Fri, 16 Feb 2018 16:02:01 +0000 (GMT) Received: from bradbury.ibm.com (unknown [9.152.222.92]) by d06av23.portsmouth.uk.ibm.com (Postfix) with ESMTP; Fri, 16 Feb 2018 16:02:01 +0000 (GMT) From: Viktor Mihajlovski To: qemu-devel@nongnu.org Date: Fri, 16 Feb 2018 17:08:38 +0100 X-Mailer: git-send-email 1.9.1 In-Reply-To: <1518797321-28356-1-git-send-email-mihajlov@linux.vnet.ibm.com> References: <1518797321-28356-1-git-send-email-mihajlov@linux.vnet.ibm.com> X-TM-AS-GCONF: 00 x-cbid: 18021616-0020-0000-0000-000003F88488 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 18021616-0021-0000-0000-0000428C88A9 Message-Id: <1518797321-28356-3-git-send-email-mihajlov@linux.vnet.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:, , definitions=2018-02-16_06:, , signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 suspectscore=1 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-1802160192 X-detected-operating-system: by eggs.gnu.org: GNU/Linux 3.x [generic] [fuzzy] X-Received-From: 148.163.158.5 Subject: [Qemu-devel] [PATCHv5 2/5] 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+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Sender: "Qemu-devel" X-Virus-Scanned: ClamAV using ClamSMTP 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 be 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 Reviewed-by: Eric Blake --- cpus.c | 38 ++++++++++++++++++++++++++++++ qapi-schema.json | 70 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 108 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; } +/* + * fast means: we NEVER interrupt vCPU threads to retrieve + * information from KVM. + */ +CpuInfoFastList *qmp_query_cpus_fast(Error **errp) +{ + MachineState *ms = MACHINE(qdev_get_machine()); + MachineClass *mc = MACHINE_GET_CLASS(ms); + CpuInfoFastList *head = NULL, *cur_item = NULL; + CPUState *cpu; + + CPU_FOREACH(cpu) { + CpuInfoFastList *info = g_malloc0(sizeof(*info)); + info->value = g_malloc0(sizeof(*info->value)); + + info->value->cpu_index = cpu->cpu_index; + info->value->qom_path = object_get_canonical_path(OBJECT(cpu)); + info->value->thread_id = cpu->thread_id; + + info->value->has_props = !!mc->cpu_index_to_instance_props; + if (info->value->has_props) { + CpuInstanceProperties *props; + props = g_malloc0(sizeof(*props)); + *props = mc->cpu_index_to_instance_props(ms, cpu->cpu_index); + info->value->props = props; + } + + if (!cur_item) { + head = cur_item = info; + } else { + cur_item->next = info; + cur_item = 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/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'] } ## +# @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