Re: [RFC PATCH v1 13/50] Avoid some useless msecs/jiffies conversions

From: George Spelvin
Date: Sun Mar 29 2020 - 08:16:01 EST


On Sun, Mar 29, 2020 at 09:52:23AM +0200, Takashi Iwai wrote:
> On Thu, 22 Aug 2019 02:25:10 +0200, George Spelvin wrote:
>> Likewise, "msecs_to_jiffies(seconds * 1000)" is more
>> conveniently written "seconds * HZ".
>
> I thought the compiler already optimizes to the constant calculation
> for the above case?

It optimizes that if the entire argument, including "seconds", is
a compile-time constant.

However, given "msecs_to_jiffies(hdev->rpa_timeout * 1000);",
the computatin is non-trivial.