linux-kernel - Re: [PATCH v2] drm/msm: Use 64-bit timekeeping

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Message-ID: <CAB__kk=CW0AKCGvRGnEw-ggxEbUNeCQ=q=PmnCVUh1oBebMBQA@mail.gmail.com>
Date:	Thu, 21 Apr 2016 04:39:04 -0700
From:	Tina Ruchandani <ruchandani.tina@...il.com>
To:	Arnd Bergmann <arnd@...db.de>
Cc:	y2038 <y2038@...ts.linaro.org>, dri-devel@...ts.freedesktop.org,
	Linux Kernel List <linux-kernel@...r.kernel.org>,
	Wentao Xu <wentaox@...eaurora.org>,
	Thierry Reding <treding@...dia.com>,
	Hai Li <hali@...eaurora.org>
Subject: Re: [PATCH v2] drm/msm: Use 64-bit timekeeping

>> which only does one 64-bit division, and it's one that we can probably
>> optimize out in the future (we can check in ktime_ms_delta whether the
>> difference is more than 2^32 nanoseconds as the fast path).

It looks like ktime_divns already has that optimization for 32-bit divisor,
so your solution should avoid the 64-bit division.