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Message-ID: <82e4877d0712170947v45929acv92e0d34c86d82c6d@mail.gmail.com>
Date: Mon, 17 Dec 2007 12:47:59 -0500
From: "Parag Warudkar" <parag.warudkar@gmail.com>
To: "Stephen Hemminger" <shemminger@linux-foundation.org>
Subject: Re: init_timer_deferrable conversion
Cc: "Eric Dumazet" <dada1@cosmosbay.com>, linux-kernel@vger.kernel.org,
       "David Miller" <davem@davemloft.net>,
       "netdev@vger.kernel.org" <netdev@vger.kernel.org>
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On Dec 17, 2007 12:00 PM, Stephen Hemminger
<shemminger@linux-foundation.org> wrote:
> > > >
> > > > a) drivers/net/sky2.c - watchdog_timer. This was showing up high on
> > > > Powertop's list of things that cause routine wakeups from idle. After
> > > > converting to init_timer_deferrable() the wakeups went down and this one
> > > > no longer shows up in powertop's list. 25% reduction.
>
> This surprises me because it is a 1 hz timer and uses round_jiffies() in
> the current kernel.

I am using the current git and I already have low wakeups per second
to begin with - 5-7  and out of that 25% are attributed to sky2. Not
sure if that matches up with the 1 hz + round_jiffies() logic.

But is it conceptually ok to make this deferrable? I suppose yes as
it's just a watchdog that checks if the link is up and delaying that
would not make a difference?

Thanks
Parag