From mboxrd@z Thu Jan 1 00:00:00 1970 From: fche@redhat.com (Frank Ch. Eigler) Subject: Re: [PATCH -tip v6 00/22] kprobes: introduce NOKPROBE_SYMBOL(), cleanup and fixes crash bugs Date: Thu, 19 Dec 2013 15:46:02 -0500 Message-ID: References: <20131219090353.14309.15496.stgit@kbuild-fedora.novalocal> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from mx1.redhat.com ([209.132.183.28]:56566 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756195Ab3LSUqV (ORCPT ); Thu, 19 Dec 2013 15:46:21 -0500 In-Reply-To: <20131219090353.14309.15496.stgit@kbuild-fedora.novalocal> (Masami Hiramatsu's message of "Thu, 19 Dec 2013 09:03:54 +0000") Sender: linux-arch-owner@vger.kernel.org List-ID: To: Masami Hiramatsu 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" 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. 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'. 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 More notes once the machine gets far enough to get to the robustness testing phase. - FChE