netdev - Re: [PATCH net-next RFC 0/5] xen-netback: TX grant mapping instead of copy

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: <5279245B.6070202@citrix.com>
Date:	Tue, 5 Nov 2013 17:01:15 +0000
From:	Zoltan Kiss <zoltan.kiss@...rix.com>
To:	Ian Campbell <Ian.Campbell@...rix.com>
CC:	<wei.liu2@...rix.com>, <xen-devel@...ts.xenproject.org>,
	<netdev@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
	<jonathan.davies@...rix.com>
Subject: Re: [PATCH net-next RFC 0/5] xen-netback: TX grant mapping instead
 of copy

On 01/11/13 19:00, Zoltan Kiss wrote:
>  >> Based on my investigations the packet get only copied if it is
> delivered to
>  >>Dom0 stack, which is due to this patch:
>  >>https://lkml.org/lkml/2012/7/20/363
>  >>That's a bit unfortunate, but as far as I know for the huge majority
> this use
>  >>case is not too important.
>> Likely to be true, but it would still be interesting to know how badly
>> this use case suffers with this change, and any increase in CPU usage
>> would be interesting to know about as well.
> I can't find my numbers, but as far as I remember it wasn't
> significantly worse than grant copy. I will check that again.
I've measured it now: with my patch it was 5.2 Gbps, without it 5.4. 
Both cases iperf in Dom0 maxed out its CPU, mostly in soft interrupt 
context, based on top.

Zoli

--
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