From nobody Tue Oct 7 05:42:06 2025 Delivered-To: importer@patchew.org Authentication-Results: mx.zohomail.com; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=pass(p=none dis=none) header.from=nongnu.org ARC-Seal: i=1; a=rsa-sha256; t=1611241779; cv=none; d=zohomail.com; s=zohoarc; b=SrCUyQNL8UVGUALgtUQapQfXuFNa+yPABzKbW7KDhTH7X2ddXwvfFlTQKRaYKT5RM8DDwyp7wh9Wt7GwGBDEjWGrZzt1sGxPDfkuAIQMb4PpU0I1ej+dj6Cmc+DMDHk5YTr18KMSMBXuNJt89lhO7dqx9vZf0e+Hgr0NtLElPpE= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.com; s=zohoarc; t=1611241779; h=Content-Transfer-Encoding:Cc:Date:From:In-Reply-To:List-Subscribe:List-Post:List-Id:List-Archive:List-Help:List-Unsubscribe:MIME-Version:Message-ID:Reply-To:References:Sender:Subject:To; bh=faXPqLWfaHzABnwWzm74VIGSkkZPc2zkZuc3Pe1rrnM=; b=HYgTMqdDx+97APxJ+X/mNaqyQrHgeSzjdB5h9iwWCdnLY71N7nbfBWYAbMr/62CB5/59G5S/ccFIzFPxt7ch2pW68fKubFlX4+rNiuORqEPyTTvfP///kfdZMZVEXvf1IJeZ6bLpt6aypy8A+35VMtSGHMq9x1cKxhEtfxHWY1k= ARC-Authentication-Results: i=1; mx.zohomail.com; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=pass header.from= (p=none dis=none) header.from= Return-Path: Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) by mx.zohomail.com with SMTPS id 1611241779448410.96939744778535; Thu, 21 Jan 2021 07:09:39 -0800 (PST) Received: from localhost ([::1]:46280 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1l2bac-00069N-9o for importer@patchew.org; Thu, 21 Jan 2021 10:09:38 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:46112) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1l2bV5-0000lR-O7 for qemu-devel@nongnu.org; Thu, 21 Jan 2021 10:03:56 -0500 Received: from relay.sw.ru ([185.231.240.75]:43648) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1l2bUy-0003y8-QG for qemu-devel@nongnu.org; Thu, 21 Jan 2021 10:03:55 -0500 Received: from [192.168.15.91] (helo=andrey-MS-7B54.sw.ru) by relay.sw.ru with esmtp (Exim 4.94) (envelope-from ) id 1l2bUj-0004cV-S7; Thu, 21 Jan 2021 18:03:33 +0300 To: qemu-devel@nongnu.org Subject: [PATCH v12 5/5] migration: introduce 'userfaultfd-wrlat.py' script Date: Thu, 21 Jan 2021 18:02:34 +0300 Message-Id: <20210121150234.192543-6-andrey.gruzdev@virtuozzo.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20210121150234.192543-1-andrey.gruzdev@virtuozzo.com> References: <20210121150234.192543-1-andrey.gruzdev@virtuozzo.com> MIME-Version: 1.0 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=185.231.240.75; envelope-from=andrey.gruzdev@virtuozzo.com; helo=relay.sw.ru X-Spam_score_int: -18 X-Spam_score: -1.9 X-Spam_bar: - X-Spam_report: (-1.9 / 5.0 requ) BAYES_00=-1.9, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham 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: , Cc: Juan Quintela , "Dr . David Alan Gilbert" , Peter Xu , Markus Armbruster , Paolo Bonzini , Den Lunev , Andrey Gruzdev Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" Reply-to: Andrey Gruzdev From: andrey.gruzdev--- via Content-Type: text/plain; charset="utf-8" Add BCC/eBPF script to analyze userfaultfd write fault latency distribution. Signed-off-by: Andrey Gruzdev Reviewed-by: Peter Xu --- 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..9c5a72df1d --- /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(); + =20 + 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 2.25.1