From: Pablo Neira Ayuso <pablo@netfilter.org>
To: Florian Westphal <fw@strlen.de>
Cc: Nadia Pinaeva <n.m.pinaeva@gmail.com>,
netfilter-devel@vger.kernel.org,
Antonio Ojea <antonio.ojea.garcia@gmail.com>
Subject: Re: [PATCH nf-next v2] netfilter: conntrack: collect start time as early as possible
Date: Wed, 6 Nov 2024 10:10:02 +0100 [thread overview]
Message-ID: <ZysyaqYhMEOzdWFm@calendula> (raw)
In-Reply-To: <20241106083438.GA1738@breakpoint.cc>
On Wed, Nov 06, 2024 at 09:34:38AM +0100, Florian Westphal wrote:
> 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?
I think ktime_get_real_ns() needs to be used to get the "event time",
I am afraid skb_tstamp() is not useful.
next prev parent reply other threads:[~2024-11-06 9:10 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-10-30 13:12 [PATCH nf-next v2] netfilter: conntrack: collect start time as early as possible Florian Westphal
2024-11-03 10:26 ` Nadia Pinaeva
2024-11-04 9:09 ` Pablo Neira Ayuso
2024-11-04 9:39 ` Florian Westphal
2024-11-04 10:03 ` Nadia Pinaeva
2024-11-04 11:09 ` Antonio Ojea
2024-11-05 16:08 ` Pablo Neira Ayuso
2024-11-05 16:23 ` Florian Westphal
2024-11-05 16:28 ` Pablo Neira Ayuso
2024-11-05 16:33 ` Florian Westphal
2024-11-05 16:45 ` Pablo Neira Ayuso
2024-11-05 17:32 ` Florian Westphal
2024-11-05 23:20 ` Pablo Neira Ayuso
2024-11-06 8:26 ` Florian Westphal
2024-11-06 8:32 ` Pablo Neira Ayuso
2024-11-06 8:34 ` Florian Westphal
2024-11-06 9:10 ` Pablo Neira Ayuso [this message]
2024-11-06 12:39 ` Florian Westphal
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