netdev - Re: Packet mmap: TX RING and zero 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: <7e0dd21a0809030056q2bfd0344kf3b86a90a4b3fc5f@mail.gmail.com>
Date:	Wed, 3 Sep 2008 09:56:25 +0200
From:	"Johann Baudy" <johaahn@...il.com>
To:	"Evgeniy Polyakov" <johnpol@....mipt.ru>
Cc:	netdev@...r.kernel.org
Subject: Re: Packet mmap: TX RING and zero copy

Hi Evgeniy,

>> I've made lot of tests, playing with jumbo frames, raw sockets, ...
>> I've never exceeded ~25Mbytes/s. So I've decided to analyze deeply the
>> packet socket transmission process.
>>
>> The main blocking point was the memcpy_fromiovec() function that is
>> located in the packet_sendmsg() of af_packet.c.
>
> Can you saturate the link with usual tcp/udp socket?

No, only ~15-20Mo/s with standard tcp/udp socket.

>
>> But, I would like to get as much criticism as possible in order to
>> start a discussion with experts about a conceivable way to mix
>> zero-copy, sk_buff management and packet socket.
>> Which is perhaps impossible with current network kernel flow ...
>
> Did you try vmsplice and splice?
> It is the preferred way to do a zero-copy.

Not yet, I will perform some tests using splice and let you know performances.

Many thanks,
Johann



-- 
Johann Baudy
johaahn@...il.com
--
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