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From: Giuseppe CAVALLARO <peppe.cavallaro@st.com>
To: David Miller <davem@davemloft.net>
Cc: <netdev@vger.kernel.org>, <alexandre.torgue@st.com>,
	<david.mckay@st.com>
Subject: Re: [PATCH (net-next.git) 04/18] stmmac: remove modulo in stmmac_xmit()
Date: Tue, 5 Jan 2016 09:56:24 +0100	[thread overview]
Message-ID: <568B8538.10101@st.com> (raw)
In-Reply-To: <20160104.223459.1663440859688328335.davem@davemloft.net>

Hi David

On 1/5/2016 4:34 AM, David Miller wrote:
> From: Giuseppe Cavallaro <peppe.cavallaro@st.com>
> Date: Mon, 4 Jan 2016 14:06:49 +0100
>
>> @@ -2056,7 +2068,10 @@ static netdev_tx_t stmmac_xmit(struct sk_buff *skb, struct net_device *dev)
>>   	priv->hw->desc->set_tx_owner(first);
>>   	wmb();
>>
>> -	priv->cur_tx++;
>> +	if (++entry >= txsize)
>> +		entry = 0;
>
> You are doing this over and over again, encapsulate it into a helper
> like "NEXT_TX(x)" or similar.
>
> Also, this is just fundamentally completely stupid.  Enforce the ring

this is not completely gentle but I share the final advice and I will 
fix that asap.

thanks for the review.

peppe

> size to be a power-of-2, then you can just go "x + 1 & (size - 1)" and
> not even have the conditional statement.
>
> Thanks.
>

  reply	other threads:[~2016-01-05  8:56 UTC|newest]

Thread overview: 30+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-01-04 13:06 [PATCHv2 (net-next.git) 00/18] stmmac: enhance driver performances and update the version Giuseppe Cavallaro
2016-01-04 13:06 ` [PATCH (net-next.git) 01/18] stmmac: share reset function between dwmac100 and dwmac1000 Giuseppe Cavallaro
2016-01-05  3:25   ` David Miller
2016-01-05  9:03     ` Giuseppe CAVALLARO
2016-01-05 18:45       ` David Miller
2016-02-01 15:54         ` Giuseppe CAVALLARO
2016-01-04 13:06 ` [PATCH (net-next.git) 02/18] stmmac: rework DMA bus setting and introduce new platform AXI structure Giuseppe Cavallaro
2016-01-05  3:29   ` David Miller
2016-01-05  9:32     ` Giuseppe CAVALLARO
2016-01-04 13:06 ` [PATCH (net-next.git) 03/18] stmmac: change descriptor layout Giuseppe Cavallaro
2016-01-04 13:06 ` [PATCH (net-next.git) 04/18] stmmac: remove modulo in stmmac_xmit() Giuseppe Cavallaro
2016-01-05  3:34   ` David Miller
2016-01-05  8:56     ` Giuseppe CAVALLARO [this message]
2016-01-04 13:06 ` [PATCH (net-next.git) 05/18] stmmac: add length field to dma data Giuseppe Cavallaro
2016-01-04 13:06 ` [PATCH (net-next.git) 06/18] stmmac: add last_segment " Giuseppe Cavallaro
2016-01-04 13:06 ` [PATCH (net-next.git) 07/18] stmmac: add is_jumbo " Giuseppe Cavallaro
2016-01-04 13:06 ` [PATCH (net-next.git) 08/18] stmmac: merge get_rx_owner into rx_status routine Giuseppe Cavallaro
2016-01-04 13:06 ` [PATCH (net-next.git) 09/18] stmmac: optimize tx desc management Giuseppe Cavallaro
2016-01-05  3:39   ` David Miller
2016-01-05  8:57     ` Giuseppe CAVALLARO
2016-01-04 13:06 ` [PATCH (net-next.git) 10/18] stmmac: optimize tx clean function Giuseppe Cavallaro
2016-01-04 13:06 ` [PATCH (net-next.git) 11/18] stmmac: set dirty index out of the loop Giuseppe Cavallaro
2016-01-04 13:06 ` [PATCH (net-next.git) 12/18] stmmac: first frame prep at the end of xmit routine Giuseppe Cavallaro
2016-01-04 13:06 ` [PATCH (net-next.git) 13/18] stmmac: perf, remove modulo in stmmac_rx() Giuseppe Cavallaro
2016-01-04 13:06 ` [PATCH (net-next.git) 14/18] stmmac: do not poll phy handler when attach a switch Giuseppe Cavallaro
2016-01-04 13:07 ` [PATCH (net-next.git) 15/18] stmmac: fix phy init when attached to a phy Giuseppe Cavallaro
2016-01-04 13:07 ` [PATCHv2 (net-next.git) 16/18] stmmac: do not perform zero-copy for rx frames Giuseppe Cavallaro
2016-01-04 13:07 ` [PATCH (net-next.git) 17/18] stmmac: tune rx copy via threshold Giuseppe Cavallaro
2016-01-04 13:07 ` [PATCH (net-next.git) 18/18] stmmac: update version to Oct_2015 Giuseppe Cavallaro
  -- strict thread matches above, loose matches on Subject: below --
2015-12-09  8:37 [PATCH (net-next.git) 00/18] stmmac: enhance driver performances and update the version Giuseppe Cavallaro
2015-12-09  8:37 ` [PATCH (net-next.git) 04/18] stmmac: remove modulo in stmmac_xmit() Giuseppe Cavallaro

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