From: Amit Kucheria <amit.kucheria@linaro.org>
To: Daniel Thompson <daniel.thompson@linaro.org>
Cc: LKML <linux-kernel@vger.kernel.org>,
linux-arm-msm <linux-arm-msm@vger.kernel.org>,
Bjorn Andersson <bjorn.andersson@linaro.org>,
Eduardo Valentin <edubezval@gmail.com>,
Andy Gross <agross@kernel.org>, Stephen Boyd <sboyd@kernel.org>,
Brian Masney <masneyb@onstation.org>,
Marc Gonzalez <marc.w.gonzalez@free.fr>,
Daniel Lezcano <daniel.lezcano@linaro.org>,
Mark Rutland <mark.rutland@arm.com>,
Rob Herring <robh+dt@kernel.org>, Zhang Rui <rui.zhang@intel.com>,
Linux PM list <linux-pm@vger.kernel.org>
Subject: Re: [PATCH v2 03/15] drivers: thermal: tsens: Add __func__ identifier to debug statements
Date: Thu, 29 Aug 2019 21:44:04 +0530 [thread overview]
Message-ID: <CAP245DWqbFnKVW9BYCzUMH=Ub+0j=3ycj-=MiPzRRW1Zv5LUmw@mail.gmail.com> (raw)
In-Reply-To: <20190829151912.z6cflsaox2qnmqxw@holly.lan>
On Thu, Aug 29, 2019 at 8:49 PM Daniel Thompson
<daniel.thompson@linaro.org> wrote:
>
> On Thu, Aug 29, 2019 at 07:58:45PM +0530, Amit Kucheria wrote:
> > On Thu, Aug 29, 2019 at 7:35 PM Daniel Thompson
> > <daniel.thompson@linaro.org> wrote:
> > >
> > > On Tue, Aug 27, 2019 at 05:43:59PM +0530, Amit Kucheria wrote:
> > > > Printing the function name when enabling debugging makes logs easier to
> > > > read.
> > > >
> > > > Signed-off-by: Amit Kucheria <amit.kucheria@linaro.org>
> > > > Reviewed-by: Stephen Boyd <swboyd@chromium.org>
> > > > Reviewed-by: Daniel Lezcano <daniel.lezcano@linaro.org>
> > >
> > > This should need to be manually added at each call site; it is already
> > > built into the logging system (the f flag for dynamic debug)?
> >
> > I assume you meant "shouldn't".
>
> Quite so. Sorry about that.
>
> > I haven't yet integrated dynamic debug into my daily workflow.
> >
> > Last time I looked at it, it was a bit bothersome to use because I
> > needed to lookup exact line numbers to trigger useful information. And
> > those line numbers constantly keep changing as I work on the driver,
> > so it was a bit painful to script. Not to mention the syntax to frob
> > the correct files in debugfs to enable this functionality.
> >
> > As opposed to this, adding the following to the makefile is so easy. :-)
> >
> > CFLAGS_tsens-common.o := -DDEBUG
> >
> > Perhaps I am using it all wrong? How would I go about using dynamic
> > debug instead of this patch?
>
> Throwing dyndbg="file <fname>.c +pf" onto the kernel command line is a
> good start (+p enables debug level prints, +f causes messages to include
> the function name).
That's useful to know.
$ git grep __func__ | wc -l
30914
Want to send some patches? :-)
> When the C files map to module names (whether the modules are actually
> built-in or not) then <module>.dyndbg=+pf is a bit cleaner and allows
> you to debug the whole of a driver without how it is decomposed into
> files.
And if changing the kernel cmdline options isn't possible or is inconvenient?
> There are (many) other controls to play with[1] but the above should be
> sufficient to simulate -DDEBUG .
The "hard" bit is explicitly poking the line number in a file to
activate a paricular pr_dbg statement. Even if I scripted it, those
lines numbers keep changing in an actively developed driver.
Somehow, I've always felt dyndbg was more useful to debug a production
system where recompiling the kernel wasn't an option e.g. reporting an
issue back to a distro-kernel vendor.
> Daniel.
>
> [1]
> https://www.kernel.org/doc/html/latest/admin-guide/dynamic-debug-howto.html
next prev parent reply other threads:[~2019-08-29 16:14 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-27 12:13 [PATCH v2 00/15] thermal: qcom: tsens: Add interrupt support Amit Kucheria
2019-08-27 12:13 ` [PATCH v2 01/15] drivers: thermal: tsens: Get rid of id field in tsens_sensor Amit Kucheria
2019-08-27 12:13 ` [PATCH v2 02/15] drivers: thermal: tsens: Simplify code flow in tsens_probe Amit Kucheria
2019-08-27 12:13 ` [PATCH v2 03/15] drivers: thermal: tsens: Add __func__ identifier to debug statements Amit Kucheria
2019-08-29 14:04 ` Daniel Thompson
2019-08-29 14:28 ` Amit Kucheria
2019-08-29 15:19 ` Daniel Thompson
2019-08-29 16:14 ` Amit Kucheria [this message]
2019-08-29 16:34 ` Daniel Thompson
2019-08-27 12:14 ` [PATCH v2 04/15] drivers: thermal: tsens: Add debugfs support Amit Kucheria
2019-08-28 0:31 ` Stephen Boyd
2019-08-27 12:14 ` [PATCH v2 07/15] dt: thermal: tsens: Document interrupt support in tsens driver Amit Kucheria
2019-08-28 0:33 ` Stephen Boyd
2019-08-29 8:48 ` Amit Kucheria
2019-08-29 14:53 ` Stephen Boyd
2019-08-29 16:34 ` Amit Kucheria
2019-08-30 11:32 ` Amit Kucheria
2019-08-30 15:55 ` Stephen Boyd
2019-08-30 16:40 ` Amit Kucheria
2019-08-27 12:14 ` [PATCH v2 14/15] drivers: thermal: tsens: Create function to return sign-extended temperature Amit Kucheria
2019-08-28 0:38 ` Stephen Boyd
[not found] ` <CAP245DVGY6+vue_REqy=Tbvka2fcBx6XhSBePW4L3=pNagX=Dw@mail.gmail.com>
2019-08-28 15:44 ` Stephen Boyd
2019-08-27 12:14 ` [PATCH v2 15/15] drivers: thermal: tsens: Add interrupt support Amit Kucheria
2019-08-28 21:42 ` Stephen Boyd
2019-08-29 12:30 ` Amit Kucheria
2019-08-29 14:54 ` Stephen Boyd
2019-08-29 3:53 ` Thara Gopinath
2019-09-10 16:01 ` Amit Kucheria
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