netdev - Re: [RFC v1] hand off skb list to other cpu to submit to upper layer

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: <20090304.013937.129768263.davem@davemloft.net>
Date:	Wed, 04 Mar 2009 01:39:37 -0800 (PST)
From:	David Miller <davem@...emloft.net>
To:	yanmin_zhang@...ux.intel.com
Cc:	herbert@...dor.apana.org.au, netdev@...r.kernel.org,
	linux-kernel@...r.kernel.org, jesse.brandeburg@...el.com,
	shemminger@...tta.com
Subject: Re: [RFC v1] hand off skb list to other cpu to submit to upper
 layer

From: "Zhang, Yanmin" <yanmin_zhang@...ux.intel.com>
Date: Wed, 04 Mar 2009 17:27:48 +0800

> Both the new skb_record_rx_queue and current kernel have an
> assumption on multi-queue. The assumption is it's best to send out
> packets from the TX of the same number of queue like the one of RX
> if the receved packets are related to the out packets. Or more
> direct speaking is we need send packets on the same cpu on which we
> receive them. The start point is that could reduce skb and data
> cache miss.

We have to use the same TX queue for all packets for the same
connection flow (same src/dst IP address and ports) otherwise
we introduce reordering.

Herbert brought this up, now I have explicitly brought this up,
and you cannot ignore this issue.

You must not knowingly reorder packets, and using different TX
queues for packets within the same flow does that.
--
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