From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753885Ab3LTEWJ (ORCPT ); Thu, 19 Dec 2013 23:22:09 -0500 Received: from mail7.hitachi.co.jp ([133.145.228.42]:40778 "EHLO mail7.hitachi.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753550Ab3LTEWG (ORCPT ); Thu, 19 Dec 2013 23:22:06 -0500 Message-ID: <52B3C5E6.2040802@hitachi.com> Date: Fri, 20 Dec 2013 13:21:58 +0900 From: Masami Hiramatsu Organization: Hitachi, Ltd., Japan User-Agent: Mozilla/5.0 (Windows NT 5.2; rv:13.0) Gecko/20120614 Thunderbird/13.0.1 MIME-Version: 1.0 To: "Frank Ch. Eigler" Cc: Ingo Molnar , linux-arch@vger.kernel.org, Ananth N Mavinakayanahalli , Sandeepa Prabhu , x86@kernel.org, lkml , "Steven Rostedt (Red Hat)" , systemtap@sourceware.org, "David S. Miller" Subject: Re: [PATCH -tip v6 00/22] kprobes: introduce NOKPROBE_SYMBOL(), cleanup and fixes crash bugs References: <20131219090353.14309.15496.stgit@kbuild-fedora.novalocal> In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org (2013/12/20 5:46), Frank Ch. Eigler wrote: > > Hi, Masami - > > > masami.hiramatsu.pt wrote: > >> Here is the version 6 of NOKPROBE_SYMBOL series. :) >> [...] > > Some preliminary results from building these on top of tip/master on > x86-64. > > # stap -te "probe kprobe.function("*") {}" > > starts up OK, without crashes, which looks like great progress. That's a good news :) > But a > closer look indicates that the insertion of kprobes is taking about > three (!!) orders of magnitude longer than before, as judged by the > rate of increase of 'wc -l /sys/kernel/debug/kprobes/list'. Right, because kprobes are not designed for thousands of probes. > So, one > has to let the thing run for several hours just to get all the kprobes > inserted, never mind letting stress-testing begin. > > For reference, here's the steady-state "perf top" output during all this > insertion work: > > 54.81% [kernel] [k] _raw_spin_unlock_irqrestore > 38.13% [kernel] [k] __slab_alloc > 1.11% [kernel] [k] kprobe_ftrace_handler > 0.88% [kernel] [k] _raw_spin_unlock_irq Hmm, interesting. Those probes are registered as disabled? Thank you, -- Masami HIRAMATSU IT Management Research Dept. Linux Technology Center Hitachi, Ltd., Yokohama Research Laboratory E-mail: masami.hiramatsu.pt@hitachi.com