netdev - Re: [PATCH net-next] tun: compute the RFS hash only if needed.

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Message-Id: <20181107.222347.231134541600778645.davem@davemloft.net>
Date:   Wed, 07 Nov 2018 22:23:47 -0800 (PST)
From:   David Miller <davem@...emloft.net>
To:     pabeni@...hat.com
Cc:     netdev@...r.kernel.org, jasowang@...hat.com
Subject: Re: [PATCH net-next] tun: compute the RFS hash only if needed.

From: Paolo Abeni <pabeni@...hat.com>
Date: Wed,  7 Nov 2018 10:34:36 +0100

> The tun XDP sendmsg code path, unconditionally computes the symmetric
> hash of each packet for RFS's sake, even when we could skip it. e.g.
> when the device has a single queue.
> 
> This change adds the check already in-place for the skb sendmsg path
> to avoid unneeded hashing.
> 
> The above gives small, but measurable, performance gain for VM xmit
> path when zerocopy is not enabled.
> 
> Signed-off-by: Paolo Abeni <pabeni@...hat.com>

Applied.