linux-kernel - Re: [PATCH v5] rtc: Improve performance of rtc_time64_to

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Message-Id: <162854698133.238383.3736740084127309703.b4-ty@bootlin.com>
Date:   Tue, 10 Aug 2021 00:10:00 +0200
From:   Alexandre Belloni <alexandre.belloni@...tlin.com>
To:     a.zummo@...ertech.it, Cassio Neri <cassio.neri@...il.com>
Cc:     Alexandre Belloni <alexandre.belloni@...tlin.com>,
        linux-kernel@...r.kernel.org, linux-rtc@...r.kernel.org,
        kernel test robot <lkp@...el.com>
Subject: Re: [PATCH v5] rtc: Improve performance of rtc_time64_to_tm(). Add tests.

On Thu, 24 Jun 2021 21:13:43 +0100, Cassio Neri wrote:
> The current implementation of rtc_time64_to_tm() contains unnecessary
> loops, branches and look-up tables. The new one uses an arithmetic-based
> algorithm appeared in [1] and is approximately 4.3 times faster (YMMV).
> 
> The drawback is that the new code isn't intuitive and contains many 'magic
> numbers' (not unusual for this type of algorithm). However, [1] justifies
> all those numbers and, given this function's history, the code is unlikely
> to need much maintenance, if any at all.
> 
> [...]

Applied, thanks!

[1/1] rtc: Improve performance of rtc_time64_to_tm(). Add tests.
      commit: 1d1bb12a8b1805ddeef9793ebeb920179fb0fa38

Best regards,
-- 
Alexandre Belloni <alexandre.belloni@...tlin.com>