From: Takashi Iwai <tiwai@suse.de>
To: George Spelvin <lkml@SDF.ORG>
Cc: linux-kernel@vger.kernel.org, Hannes Reinecke <hare@suse.de>,
linux-scsi@vger.kernel.org,
Marek Lindner <mareklindner@neomailbox.ch>,
Simon Wunderlich <sw@simonwunderlich.de>,
Antonio Quartulli <a@unstable.cc>,
Sven Eckelmann <sven@narfation.org>,
b.a.t.m.a.n@diktynna.open-mesh.org,
Johannes Berg <johannes@sipsolutions.net>,
linux-wireless@vger.kernel.org, Jaroslav Kysela <perex@perex.cz>,
Takashi Iwai <tiwai@suse.com>,
alsa-devel@alsa-project.org, lkml@sdf.org
Subject: Re: [RFC PATCH v1 13/50] Avoid some useless msecs/jiffies conversions
Date: Sun, 29 Mar 2020 19:13:33 +0200 [thread overview]
Message-ID: <s5h7dz3ccea.wl-tiwai@suse.de> (raw)
In-Reply-To: <20200329121129.GC11951@SDF.ORG>
On Sun, 29 Mar 2020 14:11:29 +0200,
George Spelvin wrote:
>
> 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.
Fair enough. But it's still a question whether an open code X * HZ is
good at all...
thanks,
Takashi
next prev parent reply other threads:[~2020-03-29 17:13 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-22 0:25 [RFC PATCH v1 13/50] Avoid some useless msecs/jiffies conversions George Spelvin
2020-03-29 7:52 ` Takashi Iwai
2020-03-29 12:11 ` George Spelvin
2020-03-29 17:13 ` Takashi Iwai [this message]
2020-03-29 17:50 ` George Spelvin
2020-03-29 18:16 ` James Bottomley
2020-03-29 21:18 ` George Spelvin
2020-03-30 6:27 ` Takashi Iwai
2020-03-30 6:51 ` George Spelvin
2020-03-30 7:29 ` Takashi Iwai
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