Skip site navigation (1)Skip section navigation (2)
Date:      Thu, 29 Jan 2015 07:07:10 -0800
From:      "Chris H" <bsd-lists@bsdforge.com>
To:        <freebsd-net@freebsd.org>
Subject:   Re: Zerocopy bpf
Message-ID:  <8c11690ac977550b52e3494351a44c78@ultimatedns.net>
In-Reply-To: <alpine.BSF.2.00.1501281625070.1717@farmermaggot.shire.sentor.se>
References:  <alpine.BSF.2.00.1501281625070.1717@farmermaggot.shire.sentor.se>

next in thread | previous in thread | raw e-mail | index | archive | help
On Thu, 29 Jan 2015 12:25:25 +0100 (CET) elof2@sentor.se wrote

> Hi!
> 
> q1)
> I assume that libpcap has builtin support for checking if sysctl
> net.bpf.zerocopy_enable is set to 1, and if so uses zerocopy.
> Correct?
> 
> q2)
> This should mean that all normal sniffing tools like tcpdump, tshark, 
> ngrep, argus, etc do NOT need any specific options in order to use 
> zerocopy.
> Correct?
> 
> q3)
> How do I see if zerocopy is used or not? 'netstat -B' don't tell me 
> much, and the tool 'bpfstat' don't seem to exist any more.
I can't speak from personal experience to the rest. But as to
bpfstat(8); it was merged into netstat(1) ~RELENG_7.

--Chris
> 
> q4)
> When activating zerocopy, should I immediately see a performance boost on 
> the machine? (like less drops on a heavily loaded sniffer NIC (running in 
> monitor mode))
> 
> /Elof
> _______________________________________________
> freebsd-net@freebsd.org mailing list
> http://lists.freebsd.org/mailman/listinfo/freebsd-net
> To unsubscribe, send any mail to "freebsd-net-unsubscribe@freebsd.org"





Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?8c11690ac977550b52e3494351a44c78>