From mboxrd@z Thu Jan 1 00:00:00 1970 From: Arnd Bergmann Subject: Re: [PATCH v2 1/5] ethernet: add sun8i-emac driver Date: Wed, 20 Jul 2016 11:56:12 +0200 Message-ID: <4697175.RMdFEWr9V5@wuerfel> References: <1469001800-11615-1-git-send-email-clabbe.montjoie@gmail.com> <1469001800-11615-2-git-send-email-clabbe.montjoie@gmail.com> Reply-To: arnd-r2nGTMty4D4@public.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Return-path: Sender: linux-sunxi-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org In-Reply-To: <1469001800-11615-2-git-send-email-clabbe.montjoie-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> List-Post: , List-Help: , List-Archive: , List-Unsubscribe: , To: linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org Cc: LABBE Corentin , robh+dt-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org, mark.rutland-5wv7dgnIgG8@public.gmane.org, maxime.ripard-wi1+55ScJUtKEb57/3fJTNBPR1lH4CV8@public.gmane.org, wens-jdAy2FN1RRM@public.gmane.org, linux-I+IVW8TIWO2tmTQ+vhA3Yw@public.gmane.org, davem-fT/PcQaiUtIeIZ0/mPfg9Q@public.gmane.org, devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, netdev-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-sunxi-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org List-Id: devicetree@vger.kernel.org On Wednesday, July 20, 2016 10:03:16 AM CEST LABBE Corentin wrote: > + > + /* Benched on OPIPC with 100M, setting more than 256 does not give any > + * perf boost > + */ > + priv->nbdesc_rx = 128; > + priv->nbdesc_tx = 256; > + > 256 tx descriptors can introduce a significant latency. Can you add support for BQL (netdev_sent_queue/netdev_completed_queue) to limit the queue size to the minimum? I also noticed that your tx_lock() prevents you from concurrently running sun8i_emac_complete_xmit() and sun8i_emac_xmit(). Is that necessary? I'd think that you can find a way to make them work concurrently. Arnd