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Date: Wed, 6 Nov 2024 09:34:38 +0100
From: Florian Westphal <fw@strlen.de>
To: Pablo Neira Ayuso <pablo@netfilter.org>
Cc: Florian Westphal <fw@strlen.de>, Nadia Pinaeva <n.m.pinaeva@gmail.com>,
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	Antonio Ojea <antonio.ojea.garcia@gmail.com>
Subject: Re: [PATCH nf-next v2] netfilter: conntrack: collect start time as
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Pablo Neira Ayuso <pablo@netfilter.org> wrote:
> > Can you clarify?  Do you mean skb_tstamp() vs ktime_get_real_ns()
> > or tstamp sampling in general?
> 
> I am referring to ktime_get_real_ns(), I remember to have measured
> 25%-30% performance drop when this is used, but I have not refreshed
> those numbers for long time.
>
> As for skb_tstamp(), I have to dig in the cost of it.

Its not about the cost, its about the sampling method.
If skb has the rx timestamp, then the event will reflect the skb
creation/rx time, not the "event time".  Did that make sense?