From: Ion Badulescu <ionut@badula.org>
To: "Dennis Cook" <cook@sandgate.com>
Cc: kernelnewbies@nl.linux.org, linux-kernel@vger.kernel.org
Subject: Re: Deactivating TCP checksumming
Date: Thu, 3 Apr 2003 23:41:40 -0500 [thread overview]
Message-ID: <200304040441.h344feY30091@moisil.badula.org> (raw)
In-Reply-To: <b6i5t1$h0t$1@main.gmane.org>
On Thu, 3 Apr 2003 15:34:59 -0500, Dennis Cook <cook@sandgate.com> wrote:
> Based on various feedback, on my RH Linux 2.4.18 kernel I tried the
> following:
>
> Set "features" bit NETIF_F_IP_CSUM set (the only feature bit set).
> In my network driver start-transmit check for "CHECKSUM_HW" in ip_summed.
> Using a small test program, use "sendfile" to copy a file to a network
> socket FD.
> Result is none of the packets presented to my network adapter driver have
> ip_summed set to CHECKSUM_HW, so the SW IP stack has already
> computed checksums.
>
> Is this mechanism possibly broken on kernel 2.4?
No, but you also need the scatter-gather bit to be set. Otherwise the
network needs to perform at least one copy to linearize the skb, thus it
will take the opportunity to checksum it at the same time so the
hardware capability of the board is not used.
Ion
--
It is better to keep your mouth shut and be thought a fool,
than to open it and remove all doubt.
next prev parent reply other threads:[~2003-04-04 4:31 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-04-01 12:12 shesha bhushan
2003-04-01 12:28 ` Matti Aarnio
2003-04-02 19:22 ` Dennis Cook
2003-04-02 20:36 ` Jeff Garzik
2003-04-02 20:47 ` Dennis Cook
2003-04-02 20:58 ` Jeff Garzik
2003-04-03 20:34 ` Dennis Cook
2003-04-03 20:47 ` Jeff Garzik
2003-04-03 20:57 ` Dennis Cook
2003-04-04 14:20 ` Jeff Garzik
2003-04-04 14:08 ` Abhishek Agrawal
2003-04-04 4:41 ` Ion Badulescu [this message]
2003-04-02 21:03 ` Richard B. Johnson
2003-04-02 21:22 ` Dennis Cook
-- strict thread matches above, loose matches on Subject: below --
2003-04-01 9:47 shesha bhushan
2003-04-01 10:58 ` Matti Aarnio
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=200304040441.h344feY30091@moisil.badula.org \
--to=ionut@badula.org \
--cc=cook@sandgate.com \
--cc=kernelnewbies@nl.linux.org \
--cc=linux-kernel@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox
all inboxes | Powered by JetHome®