lists  /  announce  owl-users  owl-dev  john-users  john-dev  passwdqc-users  yescrypt  popa3d-users  /  oss-security  kernel-hardening  musl  sabotage  tlsify  passwords  /  crypt-dev  xvendor  /  Bugtraq  Full-Disclosure  linux-kernel  linux-netdev  linux-ext4  PHC 
Open Source and information security mailing list archives
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Date:	Wed, 27 Aug 2008 00:51:58 +0400
From:	Evgeniy Polyakov <>
To:	Eric Dumazet <>
Cc:	Denys Fedoryshchenko <>,,
Subject: Re: loaded router, excessive getnstimeofday in oprofile

On Tue, Aug 26, 2008 at 10:44:56PM +0200, Eric Dumazet ( wrote:
> >Do you have any packet sockets in this system? Like running dhcp daemon?
> >
> Another way to see this problem can be to start a sniffer on the machine, 
> even with a restrictive pcap filter, to check if performance change or not. 
> (It should decrease)

Or just check /proc/net/packet iirc.
Anyway, having at least one packet socket ends up with timestamping of
each packet, so you will get fair load of getnstimeofday() in that case.

> For example, I believe that running "ping" could have the same effect
> (increasing netstamp_needed variable : every incoming packet has to be 
> timestamped)
> So beware of pings, traceroute and other networking tools...

Yup, this innocent toys can end up with this such behaviour on modern
highly loaded machines.

	Evgeniy Polyakov
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to
More majordomo info at

Powered by blists - more mailing lists