netdev - Re: [PATCH 2/5] net: mvneta: use per_cpu stats to fix an SMP lock up

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Message-ID: <20140113030227.GA18330@1wt.eu>
Date:	Mon, 13 Jan 2014 04:02:27 +0100
From:	Willy Tarreau <w@....eu>
To:	Eric Dumazet <eric.dumazet@...il.com>
Cc:	davem@...emloft.net, netdev@...r.kernel.org,
	Thomas Petazzoni <thomas.petazzoni@...e-electrons.com>,
	Gregory CLEMENT <gregory.clement@...e-electrons.com>
Subject: Re: [PATCH 2/5] net: mvneta: use per_cpu stats to fix an SMP lock up

On Sun, Jan 12, 2014 at 04:45:03PM -0800, Eric Dumazet wrote:
> On Sun, 2014-01-12 at 23:09 +0100, Willy Tarreau wrote:
> 
> > But we can have multiple tx in parallel, one per queue. And it's only
> > when I explicitly bind two servers to two distinct CPU cores that I
> > can trigger the issue, which seems to confirm that this is the cause
> > of the issue.
> 
> So this driver has multiqueue ?

Yes, it defaults to 8 queues in each direction.

> Definitely it should have one syncp per queue.
> 
> Or per cpu stats, as your patch did.

OK thank you for your review and explanation then, I'm reassured :-)

Thanks,
Willy

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