From mboxrd@z Thu Jan 1 00:00:00 1970 From: Claudiu Manoil Subject: Re: [PATCH][net-next] gianfar: Fix reported sent bytes to BQL for Tx timestamping Date: Mon, 29 Apr 2013 17:27:32 +0300 Message-ID: <517E8354.1010503@freescale.com> References: <1367240268-32609-1-git-send-email-claudiu.manoil@freescale.com> <1367243593.8964.306.camel@edumazet-glaptop> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 7bit Cc: , Paul Gortmaker , "David S. Miller" To: Eric Dumazet Return-path: Received: from tx2ehsobe004.messaging.microsoft.com ([65.55.88.14]:55133 "EHLO tx2outboundpool.messaging.microsoft.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753731Ab3D2O2r (ORCPT ); Mon, 29 Apr 2013 10:28:47 -0400 In-Reply-To: <1367243593.8964.306.camel@edumazet-glaptop> Sender: netdev-owner@vger.kernel.org List-ID: Hi, Unfortunately fixing this the other way around would imply changes in both xmit and clean_tx, and additional overhead in clean_tx. On xmit skb->len gets incremented with FCB_LEN and/or TXPAL_LEN, on a case by case basis. This would imply to add extra checks on clean_tx to identify whether only FCB_LEN has been added, or FCB+TXPAL or neither, all these just to report the bytes on wire for BQL. Does BQL really need to measure the bytes-on-wire or the bytes consumed for buffering? Thanks, Claudiu On 4/29/2013 4:53 PM, Eric Dumazet wrote: > On Mon, 2013-04-29 at 15:57 +0300, Claudiu Manoil wrote: >> When Tx timestamping is enabled the number of sent bytes reported >> to BQL via tx_completed_queue() falls short by GMAC_FCB_LEN + >> GMAC_TXPAL_LEN than the number of bytes reported via tx_sent_queue() >> on xmit. This leads to BQL stopping transmission errorneously followed >> by tx timeout firing. >> >> This fixes the amount of sent bytes reported to BQL on clean_tx_ring >> to match the amount reported on xmit, when Tx timestamping enabled. >> >> Signed-off-by: Claudiu Manoil >> --- >> drivers/net/ethernet/freescale/gianfar.c | 1 + >> 1 file changed, 1 insertion(+) >> >> diff --git a/drivers/net/ethernet/freescale/gianfar.c b/drivers/net/ethernet/freescale/gianfar.c >> index 2375a01..0d26a8b 100644 >> --- a/drivers/net/ethernet/freescale/gianfar.c >> +++ b/drivers/net/ethernet/freescale/gianfar.c >> @@ -2539,6 +2539,7 @@ static void gfar_clean_tx_ring(struct gfar_priv_tx_q *tx_queue) >> skb_tstamp_tx(skb, &shhwtstamps); >> bdp->lstatus &= BD_LFLAG(TXBD_WRAP); >> bdp = next; >> + bytes_sent += GMAC_FCB_LEN + GMAC_TXPAL_LEN; >> } >> >> bdp->lstatus &= BD_LFLAG(TXBD_WRAP); > > Technically speaking these bytes are not sent to the wire. > > I would rather fix gfar_start_xmit() to give to netdev_tx_sent_queue() > call the correct amount of bytes on wire, to be consistent with other > drivers. > > > > >