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Mon, 08 Feb 2021 06:30:24 -0500 Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-130-3VaSbUSnNCWkWC3BughC1Q-1; Mon, 08 Feb 2021 06:29:59 -0500 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 0279080402E; Mon, 8 Feb 2021 11:29:58 +0000 (UTC) Received: from dgilbert-t580.localhost (ovpn-115-22.ams2.redhat.com [10.36.115.22]) by smtp.corp.redhat.com (Postfix) with ESMTP id 0245B1002388; Mon, 8 Feb 2021 11:29:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1612783802; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=Se5PgBvmj/igHU2KtSDhk45/M6qHCrQMbFcqOM72qf0=; b=CJ9Hduhfz3nwiz/YRE1b/aGV4D2aFu7JXSf0m/Ku4hAU7wcNNpLerapgN7csWvgBLQ9CD0 t8Bt75gqYazBCRcGzYTmqfMGjlZER8anGoFYNb4MUs5QQdjxNTmyXmoMngd5S3cvw0s6Mb cpCjL80W5KvB5UWjLHawF4DAnpdgAJU= X-MC-Unique: 3VaSbUSnNCWkWC3BughC1Q-1 From: "Dr. David Alan Gilbert (git)" To: qemu-devel@nongnu.org, andrey.gruzdev@virtuozzo.com, berrange@redhat.com, gaojinhao@huawei.com, armbru@redhat.com, mst@redhat.com, philmd@redhat.com, wainersm@redhat.com, s.reiter@proxmox.com Subject: [PULL 08/27] migration: introduce 'userfaultfd-wrlat.py' script Date: Mon, 8 Feb 2021 11:28:59 +0000 Message-Id: <20210208112918.185058-9-dgilbert@redhat.com> In-Reply-To: <20210208112918.185058-1-dgilbert@redhat.com> References: <20210208112918.185058-1-dgilbert@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=dgilbert@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Transfer-Encoding: quoted-printable Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Received-SPF: pass client-ip=63.128.21.124; envelope-from=dgilbert@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -16 X-Spam_score: -1.7 X-Spam_bar: - X-Spam_report: (-1.7 / 5.0 requ) BAYES_00=-1.9, DKIM_INVALID=0.1, DKIM_SIGNED=0.1, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=no autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail-DKIM: pass (identity @redhat.com) Content-Type: text/plain; charset="utf-8" From: Andrey Gruzdev Add BCC/eBPF script to analyze userfaultfd write fault latency distribution. Signed-off-by: Andrey Gruzdev Reviewed-by: Peter Xu Message-Id: <20210129101407.103458-6-andrey.gruzdev@virtuozzo.com> Signed-off-by: Dr. David Alan Gilbert --- scripts/userfaultfd-wrlat.py | 122 +++++++++++++++++++++++++++++++++++ 1 file changed, 122 insertions(+) create mode 100755 scripts/userfaultfd-wrlat.py diff --git a/scripts/userfaultfd-wrlat.py b/scripts/userfaultfd-wrlat.py new file mode 100755 index 0000000000..0684be4e04 --- /dev/null +++ b/scripts/userfaultfd-wrlat.py @@ -0,0 +1,122 @@ +#!/usr/bin/python3 +# +# userfaultfd-wrlat Summarize userfaultfd write fault latencies. +# Events are continuously accumulated for the +# run, while latency distribution histogram is +# dumped each 'interval' seconds. +# +# For Linux, uses BCC, eBPF. +# +# USAGE: userfaultfd-lat [interval [count]] +# +# Copyright Virtuozzo GmbH, 2020 +# +# Authors: +# Andrey Gruzdev +# +# This work is licensed under the terms of the GNU GPL, version 2 or +# later. See the COPYING file in the top-level directory. + +from __future__ import print_function +from bcc import BPF +from ctypes import c_ushort, c_int, c_ulonglong +from time import sleep +from sys import argv + +def usage(): + print("USAGE: %s [interval [count]]" % argv[0]) + exit() + +# define BPF program +bpf_text =3D """ +#include +#include + +BPF_HASH(ev_start, u32, u64); +BPF_HISTOGRAM(ev_delta_hist, u64); + +/* Trace UFFD page fault start event. */ +static void do_event_start() +{ + /* Using "(u32)" to drop group ID which is upper 32 bits */ + u32 tid =3D (u32) bpf_get_current_pid_tgid(); + u64 ts =3D bpf_ktime_get_ns(); + + ev_start.update(&tid, &ts); +} + +/* Trace UFFD page fault end event. */ +static void do_event_end() +{ + /* Using "(u32)" to drop group ID which is upper 32 bits */ + u32 tid =3D (u32) bpf_get_current_pid_tgid(); + u64 ts =3D bpf_ktime_get_ns(); + u64 *tsp; + + tsp =3D ev_start.lookup(&tid); + if (tsp) { + u64 delta =3D ts - (*tsp); + /* Transform time delta to milliseconds */ + ev_delta_hist.increment(bpf_log2l(delta / 1000000)); + ev_start.delete(&tid); + } +} + +/* KPROBE for handle_userfault(). */ +int probe_handle_userfault(struct pt_regs *ctx, struct vm_fault *vmf, + unsigned long reason) +{ + /* Trace only UFFD write faults. */ + if (reason & VM_UFFD_WP) { + do_event_start(); + } + return 0; +} + +/* KRETPROBE for handle_userfault(). */ +int retprobe_handle_userfault(struct pt_regs *ctx) +{ + do_event_end(); + return 0; +} +""" + +# arguments +interval =3D 10 +count =3D -1 +if len(argv) > 1: + try: + interval =3D int(argv[1]) + if interval =3D=3D 0: + raise + if len(argv) > 2: + count =3D int(argv[2]) + except: # also catches -h, --help + usage() + +# load BPF program +b =3D BPF(text=3Dbpf_text) +# attach KRPOBEs +b.attach_kprobe(event=3D"handle_userfault", fn_name=3D"probe_handle_userfa= ult") +b.attach_kretprobe(event=3D"handle_userfault", fn_name=3D"retprobe_handle_= userfault") + +# header +print("Tracing UFFD-WP write fault latency... Hit Ctrl-C to end.") + +# output +loop =3D 0 +do_exit =3D 0 +while (1): + if count > 0: + loop +=3D 1 + if loop > count: + exit() + try: + sleep(interval) + except KeyboardInterrupt: + pass; do_exit =3D 1 + + print() + b["ev_delta_hist"].print_log2_hist("msecs") + if do_exit: + exit() --=20 2.29.2