From: Willy Tarreau <willy@w.ods.org>
To: Conio sandiago <coniodiago@gmail.com>
Cc: linux-kernel@vger.kernel.org
Subject: Re: Un aligned addresses
Date: Fri, 23 Dec 2005 00:28:55 +0100 [thread overview]
Message-ID: <20051222232855.GO15993@alpha.home.local> (raw)
In-Reply-To: <993d182d0512212236u525b6f25wf1dcaae9c389537f@mail.gmail.com>
On Thu, Dec 22, 2005 at 12:06:46PM +0530, Conio sandiago wrote:
> Hi all
> i have a embedded monta vista linux running.
> i have developed a ethernet driver.
> Its working Ok,
> But i am facing some problem with the throughput.
>
> After a lot of observation ,
> i observed that i am getting un-aligned addresses of the data payload
> from the TCP/IP stack.because of this problem i always have to do
> memcpy to a word aligned buffer,because of which throughput is reduced
> significantly.
>
> Does anybody has some solution for this.
I guess your driver is not working that much OK yet. Many (most)
ethernet boards today will align the IP header on a 4 or 16 bytes boundary.
By default, the ethernet header being 14 bytes, it unaligns the IP header.
But some boards will leave a hole between those. Probably that your driver
needs to tell the hardware to do this. Or maybe you can program the DMA
to get on 4x+2 so that IP gets aligned ?
Anyway, I don't know whether I'm loosing my time because last time
you sent such a report about your driver, I asked for a little more
precisions, which I never received.
> Regards
> conio
Willy
prev parent reply other threads:[~2005-12-22 23:29 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-12-22 6:36 Conio sandiago
2005-12-22 7:31 ` David S. Miller
2005-12-22 23:28 ` Willy Tarreau [this message]
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