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From: "George Spelvin" <linux@horizon.com>
To: grantgrundler@gmail.com, linux@horizon.com
Cc: eric.dumazet@gmail.com, grundler@parisc-linux.org,
	netdev@vger.kernel.org
Subject: Re: [RFC] tulip: Support for byte queue limits
Date: 12 Jul 2013 14:01:16 -0400	[thread overview]
Message-ID: <20130712180116.21176.qmail@science.horizon.com> (raw)
In-Reply-To: <CAP6odjhsL8QPKwurP_H88M3kAoBW-z_jGHtEhL0Tj7AfZNutHA@mail.gmail.com>

> Hi George,
> While you are right that functionally it doesn't matter, my preference
> would be to have nothing between the wmb() and iowrite() that kicks
> off the TX. This marginally helps kick off the TX process consistently
> slightly sooner. On modern HW, probably irrelevant, but not on the HW
> these chips are used on.

I'll revise it.  It just made sense to me to put it next to the other
bookkeeping line of tp->cur_tx++.  Should I move them both below the
iowrite()?  As in:

--- a/drivers/net/ethernet/dec/tulip/tulip_core.c
+++ b/drivers/net/ethernet/dec/tulip/tulip_core.c
@@ -702,11 +702,11 @@ tulip_start_xmit(struct sk_buff *skb, struct net_device *dev)
 	tp->tx_ring[entry].status = cpu_to_le32(DescOwned);
 	wmb();
 
-	tp->cur_tx++;
-
 	/* Trigger an immediate transmit demand. */
 	iowrite32(0, tp->base_addr + CSR1);
 
+	tp->cur_tx++;
+	netdev_sent_queue(dev, skb->len);
 	spin_unlock_irqrestore(&tp->lock, flags);
 
 	return NETDEV_TX_OK;

> Lastly, given I haven't powered up a system in two years which has
> tulip, any one want to take over maintainer for tulip driver?
> It's basically obsolete with a few rare patches like this one coming in.

I'm not up to it myself, sorry.

  reply	other threads:[~2013-07-12 18:01 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-07-12 13:20 [RFC] tulip: Support for byte queue limits George Spelvin
2013-07-12 13:39 ` Eric Dumazet
2013-07-12 16:31 ` Grant Grundler
2013-07-12 18:01   ` George Spelvin [this message]
2013-07-12 18:14     ` Grant Grundler
2013-07-15 23:58     ` Ben Hutchings
2013-07-16  1:17       ` Grant Grundler
2013-07-16  1:27         ` Eric Dumazet
2013-07-16 14:37         ` Ben Hutchings
2013-07-16 17:20           ` Grant Grundler
2013-07-17  4:09       ` George Spelvin
2013-07-17 15:42         ` Ben Hutchings
2013-07-31 12:34           ` George Spelvin

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