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Re: [PATCH -tip v6 00/22] kprobes: introduce NOKPROBE_SYMBOL(), cleanup and fixes crash bugs
- From: Ingo Molnar <mingo at kernel dot org>
- To: Masami Hiramatsu <masami dot hiramatsu dot pt at hitachi dot com>
- Cc: "Frank Ch. Eigler" <fche at redhat dot com>, linux-arch at vger dot kernel dot org, Ananth N Mavinakayanahalli <ananth at in dot ibm dot com>, Sandeepa Prabhu <sandeepa dot prabhu at linaro dot org>, x86 at kernel dot org, lkml <linux-kernel at vger dot kernel dot org>, "Steven Rostedt (Red Hat)" <rostedt at goodmis dot org>, systemtap at sourceware dot org, "David S. Miller" <davem at davemloft dot net>
- Date: Mon, 23 Dec 2013 14:04:38 +0100
- Subject: Re: [PATCH -tip v6 00/22] kprobes: introduce NOKPROBE_SYMBOL(), cleanup and fixes crash bugs
- Authentication-results: sourceware.org; auth=none
- References: <20131219090353 dot 14309 dot 15496 dot stgit at kbuild-fedora dot novalocal> <y0m38loefhx dot fsf at fche dot csb> <52B3C5E6 dot 2040802 at hitachi dot com> <20131220082056 dot GA15934 at gmail dot com> <52B40E79 dot 8040701 at hitachi dot com> <20131220104615 dot GA22609 at gmail dot com> <52B75542 dot 7040600 at hitachi dot com>
* Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> wrote:
> > I can reproduce one weirdness, with just 13 probes added, 'perf probe
> > -l' [which should really be 'perf probe list'!] executes very slowly:
> >
> > # perf stat --null --repeat 3 perf probe -l
> >
> > Performance counter stats for 'perf probe -l' (3 runs):
> >
> > 0.763640098 seconds time elapsed ( +- 1.61% )
> >
> > 0.7 seconds is ridiculously long.
>
> This comes from the perf-probe's internal issue. It tries to get
> actual lines and files by using debuginfo. I guess most of the time
> consumed when processing huge kernel debuginfo.
No, I don't have any debuginfo, I never use it.
Thanks,
Ingo