From: Christoph Lameter <cl@linux-foundation.org>
To: Evgeniy Polyakov <johnpol@2ka.mipt.ru>
Cc: Johann Baudy <johaahn@gmail.com>,
David Miller <davem@davemloft.net>,
netdev@vger.kernel.org
Subject: Re: Packet mmap: TX RING and zero copy
Date: Wed, 03 Sep 2008 09:57:46 -0500 [thread overview]
Message-ID: <48BEA5EA.3050809@linux-foundation.org> (raw)
In-Reply-To: <20080903132734.GA17541@2ka.mipt.ru>
Evgeniy Polyakov wrote:
> Hi Johann.
>
> On Wed, Sep 03, 2008 at 03:05:07PM +0200, Johann Baudy (johaahn@gmail.com) wrote:
>> TCP socket, transferring 20Mbytes file (located in initramfs) in loop
>> with sendfile() : 5.7Mbytes/s
>
> And _THIS_ is a serious problem. Let's assume that sendfile is broken or
> driver/hardware does not support scatter/gather and checksumming (does it?).
> Can you saturate the link with pktgen (1) and usual tcp socket (2).
> Assuming second case will fail, does it also broken because of very
> small performance of the copy from the userspace?
Could we see the code that was used to get these numbers? The problem may just
be in the way that the calls to sendfile() have been coded.
The TX code looks intriguing. Seems that some vendors are tinkering with VNIC
ideas in order to bypass context switches and data copies. Maybe this is a
cheap way to attain the same goals?
next prev parent reply other threads:[~2008-09-03 14:58 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-09-02 18:27 Packet mmap: TX RING and zero copy Johann Baudy
2008-09-02 19:46 ` Evgeniy Polyakov
2008-09-03 7:56 ` Johann Baudy
2008-09-03 10:38 ` Johann Baudy
2008-09-03 11:06 ` David Miller
2008-09-03 13:05 ` Johann Baudy
2008-09-03 13:27 ` Evgeniy Polyakov
2008-09-03 14:57 ` Christoph Lameter [this message]
2008-09-03 15:00 ` Johann Baudy
2008-09-03 15:13 ` Evgeniy Polyakov
2008-09-03 15:58 ` Johann Baudy
2008-09-03 16:43 ` Evgeniy Polyakov
2008-09-03 20:30 ` Johann Baudy
2008-09-03 22:03 ` Evgeniy Polyakov
2008-09-04 14:44 ` Johann Baudy
2008-09-05 7:17 ` Evgeniy Polyakov
[not found] ` <7e0dd21a0809050216r65b8f08fm1ad0630790a13a54@mail.gmail.com>
2008-09-05 9:17 ` Fwd: " Johann Baudy
2008-09-05 11:31 ` Evgeniy Polyakov
2008-09-05 12:44 ` Johann Baudy
2008-09-05 13:16 ` Evgeniy Polyakov
2008-09-05 13:29 ` Johann Baudy
2008-09-05 13:37 ` Evgeniy Polyakov
2008-09-05 13:55 ` Johann Baudy
2008-09-05 14:19 ` Evgeniy Polyakov
2008-09-05 14:45 ` Johann Baudy
2008-09-05 14:59 ` Evgeniy Polyakov
2008-09-05 15:30 ` Johann Baudy
2008-09-05 15:38 ` Evgeniy Polyakov
2008-09-05 16:01 ` Johann Baudy
2008-09-05 16:34 ` Evgeniy Polyakov
2008-09-08 10:21 ` Johann Baudy
2008-09-08 11:26 ` Evgeniy Polyakov
2008-09-08 13:01 ` Johann Baudy
2008-09-08 15:28 ` Evgeniy Polyakov
2008-09-08 15:38 ` Evgeniy Polyakov
2008-09-09 23:11 ` Johann Baudy
2008-09-10 6:09 ` Evgeniy Polyakov
2008-09-05 10:28 ` Robert Iakobashvili
2008-09-05 13:06 ` Johann Baudy
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