linux-kernel - Re: [PATCH v1] regmap: introduce value tracing for regmap bulk operations

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Message-ID: <87mtc1wtjz.wl-maz@kernel.org>
Date:   Thu, 18 Aug 2022 14:49:20 +0100
From:   Marc Zyngier <maz@...nel.org>
To:     Dmitry Rokosov <DDRokosov@...rdevices.ru>
Cc:     "broonie@...nel.org" <broonie@...nel.org>,
        "gregkh@...uxfoundation.org" <gregkh@...uxfoundation.org>,
        "rafael@...nel.org" <rafael@...nel.org>,
        "jic23@...nel.org" <jic23@...nel.org>,
        "linux@...musvillemoes.dk>" <linux@...musvillemoes.dk>,
        "tglx@...utronix.de" <tglx@...utronix.de>,
        "andy.shevchenko@...il.com" <andy.shevchenko@...il.com>,
        kernel <kernel@...rdevices.ru>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v1] regmap: introduce value tracing for regmap bulk operations

On Thu, 18 Aug 2022 13:15:00 +0100,
Dmitry Rokosov <DDRokosov@...rdevices.ru> wrote:
> 
> +Thomas, Rasmus and Marc
> 
> On Tue, Aug 16, 2022 at 06:14:48PM +0000, Dmitry Rokosov wrote:
> > Currently, only one-register io operations support tracepoints with
> > value logging. For the regmap bulk operations developer can view
> > hw_start/hw_done tracepoints with starting reg number and registers
> > count to be reading or writing. This patch injects tracepoints with
> > dumping registers values in the hex format to regmap bulk reading
> > and writing.

I don't care much about regmap as a MMIO backend, but it strikes me as
odd that you end up with multiple ways of logging the same stuff (with
a memcpy in the middle of it).

Why can't this be done with a small amount of trace post-processing?

	M.

-- 
Without deviation from the norm, progress is not possible.