From: Marc Gonzalez <marc.w.gonzalez@free.fr>
To: Dmitry Torokhov <dmitry.torokhov@gmail.com>,
Bjorn Andersson <bjorn.andersson@linaro.org>
Cc: linux-clk <linux-clk@vger.kernel.org>,
Linux ARM <linux-arm-kernel@lists.infradead.org>,
LKML <linux-kernel@vger.kernel.org>,
Stephen Boyd <sboyd@kernel.org>,
Michael Turquette <mturquette@baylibre.com>,
Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>,
Russell King <rmk+kernel@armlinux.org.uk>,
Sudip Mukherjee <sudipm.mukherjee@gmail.com>,
Guenter Roeck <linux@roeck-us.net>
Subject: Re: [PATCH v1] clk: Convert managed get functions to devm_add_action API
Date: Mon, 2 Dec 2019 10:25:37 +0100 [thread overview]
Message-ID: <f177ef95-ef7e-cab0-1322-6de28f18ecdb@free.fr> (raw)
In-Reply-To: <20191202014237.GR248138@dtor-ws>
On 02/12/2019 02:42, Dmitry Torokhov wrote:
> On Thu, Nov 28, 2019 at 10:56:30AM -0800, Bjorn Andersson wrote:
>
>> On Tue 26 Nov 08:13 PST 2019, Marc Gonzalez wrote:
>>
>>> Date: Tue, 26 Nov 2019 13:56:53 +0100
>>>
>>> Using devm_add_action_or_reset() produces simpler code and smaller
>>> object size:
>>>
>>> 1 file changed, 16 insertions(+), 46 deletions(-)
>>>
>>> text data bss dec hex filename
>>> - 1797 80 0 1877 755 drivers/clk/clk-devres.o
>>> + 1499 56 0 1555 613 drivers/clk/clk-devres.o
>>>
>>> Signed-off-by: Marc Gonzalez <marc.w.gonzalez@free.fr>
>>
>> Looks neat
>>
>> Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>
>
> This however increases the runtime costs as each custom action cost us
> an extra pointer. Given that in a system we likely have many clocks
> managed by devres, I am not sure that this code savings is actually
> gives us overall win. It might still, I just want to understand how we
> are allocating/packing devres structures.
I'm not 100% sure what you are saying.
Are you arguing that the proposed patch increases the run-time cost of
devm_clk_put() so much that the listed improvements (simpler source code,
smaller object size) are not worth it?
AFAIU, the release action is only called
- explicitly, when devm_clk_put() is called
- implicitly, when the device is removed
How often are clocks removed?
In hot code-path (called hundreds of times per second) it makes sense to
write more complex code, to shave a few cycles every iteration. But in
cold code-path, I think it's better to write short/simple code.
Regards.
next prev parent reply other threads:[~2019-12-02 9:25 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-11-26 16:13 [PATCH v1] clk: Convert managed get functions to devm_add_action API Marc Gonzalez
2019-11-28 18:56 ` Bjorn Andersson
2019-12-02 1:42 ` Dmitry Torokhov
2019-12-02 9:25 ` Marc Gonzalez [this message]
2019-12-02 13:51 ` Robin Murphy
2019-12-11 16:17 ` Marc Gonzalez
2019-12-11 22:28 ` Dmitry Torokhov
2019-12-12 13:53 ` Marc Gonzalez
2019-12-12 14:17 ` Russell King - ARM Linux admin
2019-12-12 14:41 ` Marc Gonzalez
2019-12-12 14:46 ` Russell King - ARM Linux admin
2019-12-12 15:51 ` Marc Gonzalez
2019-12-12 16:13 ` Russell King - ARM Linux admin
2019-12-12 14:47 ` Robin Murphy
2019-12-12 16:59 ` Marc Gonzalez
2019-12-12 17:05 ` Russell King - ARM Linux admin
2019-12-12 18:15 ` Robin Murphy
2019-12-12 19:10 ` Dmitry Torokhov
2019-12-12 21:08 ` Robin Murphy
2019-12-13 0:16 ` Dmitry Torokhov
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