netdev - Re: [PATCH v2] tcp: syncookies: do not use getnstimeofday()

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Message-ID: <20140320084527.GB5080@breakpoint.cc>
Date:	Thu, 20 Mar 2014 09:45:27 +0100
From:	Florian Westphal <fw@...len.de>
To:	Eric Dumazet <eric.dumazet@...il.com>
Cc:	netdev@...r.kernel.org
Subject: Re: [PATCH v2] tcp: syncookies: do not use getnstimeofday()

Eric Dumazet <eric.dumazet@...il.com> wrote:
> From: Eric Dumazet <edumazet@...gle.com>
> 
> While it is true that getnstimeofday() uses about 40 cycles if TSC
> is available, it can use 1600 cycles if hpet is the clocksource.
> 
> Switch to get_jiffies_64(), as this is more than enough, and
> go back to 60 seconds periods.
> 
> Fixes: 8c27bd75f04f ("tcp: syncookies: reduce cookie lifetime to 128 seconds")
> Signed-off-by: Eric Dumazet <edumazet@...gle.com>
> Cc: Florian Westphal <fw@...len.de>

Acked-by: Florian Westphal <fw@...len.de>
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