Date: Sat, 10 Jan 2009 00:06:41 +0100
From: Willy Tarreau <w@1wt.eu>
To: Evgeniy Polyakov <zbr@ioremap.net>
Cc: Eric Dumazet <dada1@cosmosbay.com>, David Miller <davem@davemloft.net>,
       ben@zeus.com, jarkao2@gmail.com, mingo@elte.hu,
       linux-kernel@vger.kernel.org, netdev@vger.kernel.org,
       jens.axboe@oracle.com
Subject: Re: [PATCH] tcp: splice as many packets as possible at once
Message-ID: <20090109230641.GD4819@1wt.eu>
References: <49677074.5090802@cosmosbay.com> <20090109185448.GA1999@1wt.eu> <4967B8C5.10803@cosmosbay.com> <20090109212400.GA3727@1wt.eu> <20090109220737.GA4111@1wt.eu> <4967CBB9.1060403@cosmosbay.com> <20090109221744.GA4819@1wt.eu> <20090109224258.GA10257@ioremap.net> <20090109225010.GB4819@1wt.eu> <20090109230124.GA11592@ioremap.net>
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On Sat, Jan 10, 2009 at 02:01:24AM +0300, Evgeniy Polyakov wrote:
> On Fri, Jan 09, 2009 at 11:50:10PM +0100, Willy Tarreau (w@1wt.eu) wrote:
> > Well, I'm now trying to educate myself on the send part. It's still
> > not very clear to me and I'd like to understand a little bit better
> > why we have this corruption problem and why there is a difference
> > between sending segments from memory and sending them from another
> > socket where they were already waiting.
> 
> printks are the best choice, since you will get exactly what you are
> looking for instead of deciphering what developer or code told you.

I know, but as I told in an earlier mail, it was not even clear to
me what function were called. I have made guesses but that's quite
hard when you don't know the entry point. I think I'm not too far
from having discovered the call chain. Understanding it will be
another story, of course ;-)

> > I think I'll put printks everywhere and see what I can observe.
> > Knowing about the GSO/SG workaround already helps me enable/disable
> > the bug.
> 
> I wish I could also be capable to disable the bugs... :)

Me too :-)
Here we have an opportunity to turn it on/off, let's take it !

Willy

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