From: Steven Rostedt <rostedt@goodmis.org>
To: Thomas Preisner <linux@tpreisner.de>
Cc: Ingo Molnar <mingo@redhat.com>, Jonathan Corbet <corbet@lwn.net>,
linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] ftrace: add simple oneshot function tracer
Date: Wed, 29 May 2019 10:45:52 -0400 [thread overview]
Message-ID: <20190529104552.146fa97c@oasis.local.home> (raw)
In-Reply-To: <20190529093124.2872-1-linux@tpreisner.de>
On Wed, 29 May 2019 11:31:23 +0200
Thomas Preisner <linux@tpreisner.de> wrote:
> The "oneshot" tracer records every address (ip, parent_ip) exactly once.
> As a result, "oneshot" can be used to efficiently create kernel function
> coverage/usage reports such as in undertaker-tailor[0].
>
> In order to provide this functionality, "oneshot" uses a
> configurable hashset for blacklisting already recorded addresses. This
> way, no user space application is required to parse the function
> tracer's output and to deactivate functions after they have been
> recorded once. Additionally, the tracer's output is reduced to a bare
> mininum so that it can be passed directly to undertaker-tailor.
>
> Further information regarding this oneshot function tracer can also be
> found at [1].
>
> [0]: https://undertaker.cs.fau.de
> [1]: https://tpreisner.de/pub/ba-thesis.pdf
>
> Signed-off-by: Thomas Preisner <linux@tpreisner.de>
>
Hi,
If you are only interested in seeing what functions are called (and
don't care about the order), why not just make another function
profiler (see register_ftrace_profiler and friends)? Then you could
just list the hash table entries instead of having to record into the
ftrace ring buffer.
-- Steve
next prev parent reply other threads:[~2019-05-29 14:45 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-05-29 9:31 [PATCH] ftrace: add simple oneshot function tracer Thomas Preisner
2019-05-29 14:45 ` Steven Rostedt [this message]
2019-06-11 20:33 ` [PATCH v2] ftrace: add simple oneshot function profiler Thomas Preisner
[not found] ` <20190611203312.13653-1-linux@tpreisner.de>
2019-06-11 21:52 ` [PATCH] ftrace: add simple oneshot function tracer Steven Rostedt
2019-06-12 21:29 ` Thomas Preisner
2019-06-18 0:16 ` Steven Rostedt
2019-06-23 12:05 ` Thomas Preisner
2019-06-26 16:04 ` Steven Rostedt
2019-07-09 13:53 ` Thomas Preisner
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