netdev - Re: Packet time delays on multi-core systems

lists.openwall.net		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 linux-hardening linux-cve-announce 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]

Message-ID: <20100930123048.GA4094@beaver.vrungel.ru>
Date:	Thu, 30 Sep 2010 16:30:48 +0400
From:	Alexey Vlasov <renton@...ton.name>
To:	Eric Dumazet <eric.dumazet@...il.com>
Cc:	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
	netdev <netdev@...r.kernel.org>
Subject: Re: Packet time delays on multi-core systems

On Wed, Sep 29, 2010 at 11:45:21PM +0200, Eric Dumazet wrote:
> But if you send SYN packets in the same time, (logged), this might
> slow
> down the reception (and answers) of ICMP frames. LOG target can be
> quite
> expensive...

Yes, it's clear that  some slow down can appear, but 100 ms is too much,
and this happens at 200 SYN packets in 2 minutes just as in my example.
On old servers where some tx/rx are missing in NIC card I don't see
such a situation even at more then 1000 SYN-packets per sec.

> Is using other rules gives same problem ?
>
> iptables -A OUTPUT -p tcp -m tcp --dport 80 --tcp-flags

No, only LOG gives such a scheme.

-- 
BRGDS. Alexey Vlasov.
--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html