| Message ID | 1238072077-27044-2-git-send-email-Joakim.Tjernlund@transmode.se |
|---|---|
| State | Superseded, archived |
| Delegated to: | David Miller |
| Headers | show |
Hi Joakim, On Thu, Mar 26, 2009 at 01:54:37PM +0100, Joakim Tjernlund wrote: > The line: > if ((bd == ugeth->txBd[txQ]) && (netif_queue_stopped(dev) == 0)) > break; > in ucc_geth_tx() didn not make sense to me. Rework & cleanup > this logic to something understandable. > > Signed-off-by: Joakim Tjernlund <Joakim.Tjernlund@transmode.se> > --- > drivers/net/ucc_geth.c | 40 ++++++++++++++++++++-------------------- > 1 files changed, 20 insertions(+), 20 deletions(-) > > diff --git a/drivers/net/ucc_geth.c b/drivers/net/ucc_geth.c > index 7fc91aa..b6ebefd 100644 > --- a/drivers/net/ucc_geth.c > +++ b/drivers/net/ucc_geth.c > @@ -3048,6 +3048,7 @@ static int ucc_geth_start_xmit(struct sk_buff *skb, struct net_device *dev) > u8 __iomem *bd; /* BD pointer */ > u32 bd_status; > u8 txQ = 0; > + int txInd; camelCase should not be used in Linux. Surely, the driver is full of camelCases... though, it should be fixed, not encouraged further. And btw, there is even Hungarian notation in the driver. :-( [...] > /* If the next BD still needs to be cleaned up, then the bds > are full. We need to tell the kernel to stop sending us stuff. */ > - if (bd == ugeth->confBd[txQ]) { > - if (!netif_queue_stopped(dev)) > - netif_stop_queue(dev); > + if (!in_be32((u32 __iomem *)(bd+4))) { bd == ugeth->confBd[txQ] and !in_be32((u32 __iomem *)(bd+4)) Are not equivalent wrt. speed. MMIO accessors should be rather slow comparing to normal memory. We should really do some performance tests (using gbit links). I'll try to help you with the tests, but it might take some time. [...] > + if (!in_be32((u32 __iomem *)(bd+4))) [...] > + out_be32((u32 __iomem *)(bd+4), (int)NULL); /* Mark it free */ How about some inline function that will self-document the bd + 4 stuff? Plus that way we'll get rid of the casts. Note that "bd+4" should be "bd + 4". And (int)NULL makes little sense, just 0 will work. Thanks,
Anton Vorontsov <avorontsov@ru.mvista.com> wrote on 26/03/2009 14:39:18: > > Hi Joakim, Hi Anton > > On Thu, Mar 26, 2009 at 01:54:37PM +0100, Joakim Tjernlund wrote: > > The line: > > if ((bd == ugeth->txBd[txQ]) && (netif_queue_stopped(dev) == 0)) > > break; > > in ucc_geth_tx() didn not make sense to me. Rework & cleanup > > this logic to something understandable. > > > > Signed-off-by: Joakim Tjernlund <Joakim.Tjernlund@transmode.se> > > --- > > drivers/net/ucc_geth.c | 40 ++++++++++++++++++++-------------------- > > 1 files changed, 20 insertions(+), 20 deletions(-) > > > > diff --git a/drivers/net/ucc_geth.c b/drivers/net/ucc_geth.c > > index 7fc91aa..b6ebefd 100644 > > --- a/drivers/net/ucc_geth.c > > +++ b/drivers/net/ucc_geth.c > > @@ -3048,6 +3048,7 @@ static int ucc_geth_start_xmit(struct sk_buff *skb, struct net_device *dev) > > u8 __iomem *bd; /* BD pointer */ > > u32 bd_status; > > u8 txQ = 0; > > + int txInd; > > camelCase should not be used in Linux. > > Surely, the driver is full of camelCases... though, it should be > fixed, not encouraged further. OK, I will rename to tx_ind instead. > > And btw, there is even Hungarian notation in the driver. :-( Hopefully that will go away in time. > > [...] > > /* If the next BD still needs to be cleaned up, then the bds > > are full. We need to tell the kernel to stop sending us stuff. */ > > - if (bd == ugeth->confBd[txQ]) { > > - if (!netif_queue_stopped(dev)) > > - netif_stop_queue(dev); > > + if (!in_be32((u32 __iomem *)(bd+4))) { > > bd == ugeth->confBd[txQ] > and > !in_be32((u32 __iomem *)(bd+4)) > > Are not equivalent wrt. speed. MMIO accessors should be rather > slow comparing to normal memory. Yes, I know. I did it this way because I something broke under stress when ugeth->confBd[txQ] instead. The ucc_geth_tx() and ucc_geth_start_xmit() gets out of sync somehow. > > We should really do some performance tests (using gbit links). > I'll try to help you with the tests, but it might take some time. Good, because I don't have GBE links :( > > [...] > > + if (!in_be32((u32 __iomem *)(bd+4))) > [...] > > + out_be32((u32 __iomem *)(bd+4), (int)NULL); /* Mark it free */ > > How about some inline function that will self-document the bd + 4 > stuff? Plus that way we'll get rid of the casts. Good idea, will look at that. > > Note that "bd+4" should be "bd + 4". And (int)NULL makes > little sense, just 0 will work. Sure, done. -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Thu, Mar 26, 2009 at 05:43:25PM +0100, Joakim Tjernlund wrote: [...] > > bd == ugeth->confBd[txQ] > > and > > !in_be32((u32 __iomem *)(bd+4)) > > > > Are not equivalent wrt. speed. MMIO accessors should be rather > > slow comparing to normal memory. > > Yes, I know. I did it this way because I something broke under stress > when ugeth->confBd[txQ] instead. The ucc_geth_tx() and > ucc_geth_start_xmit() > gets out of sync somehow. Would be great if you could investigate it more. Maybe there is a serious bug somewhere, or maybe you're introducing another (yet hidden) bug...
Anton Vorontsov <avorontsov@ru.mvista.com> wrote on 26/03/2009 19:05:43: > On Thu, Mar 26, 2009 at 05:43:25PM +0100, Joakim Tjernlund wrote: > [...] > > > bd == ugeth->confBd[txQ] > > > and > > > !in_be32((u32 __iomem *)(bd+4)) > > > > > > Are not equivalent wrt. speed. MMIO accessors should be rather > > > slow comparing to normal memory. > > > > Yes, I know. I did it this way because I something broke under stress > > when ugeth->confBd[txQ] instead. The ucc_geth_tx() and > > ucc_geth_start_xmit() > > gets out of sync somehow. > > Would be great if you could investigate it more. Maybe there is > a serious bug somewhere, or maybe you're introducing another > (yet hidden) bug... I have spent some time on it and didn't see how to do it. I don't think the current method hides any bugs. I have used this method on 8xx for many years and it works well. Actually the current method might work without the spin_lock_irq(&ugeth->lock)/spin_unlock_irq(&ugeth->lock) in ucc_geth_start_xmit(). I can't break it, can you? Jocke -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
These patches don't apply to the current tree, could you please respin your final version against at the very least Linus's tree? Thanks. -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
David Miller <davem@davemloft.net> wrote on 27/03/2009 08:42:37: > > > These patches don't apply to the current tree, could you please > respin your final version against at the very least Linus's tree? That is strange, had a look at linus tree and I don't see any changes in his tree that touches the same area/functions. If I get the time I will look at it a bit more but for now I am stuck on 2.6.29 Jocke -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/drivers/net/ucc_geth.c b/drivers/net/ucc_geth.c index 7fc91aa..b6ebefd 100644 --- a/drivers/net/ucc_geth.c +++ b/drivers/net/ucc_geth.c @@ -3048,6 +3048,7 @@ static int ucc_geth_start_xmit(struct sk_buff *skb, struct net_device *dev) u8 __iomem *bd; /* BD pointer */ u32 bd_status; u8 txQ = 0; + int txInd; ugeth_vdbg("%s: IN", __func__); @@ -3059,12 +3060,12 @@ static int ucc_geth_start_xmit(struct sk_buff *skb, struct net_device *dev) bd = ugeth->txBd[txQ]; bd_status = in_be32((u32 __iomem *)bd); /* Save the skb pointer so we can free it later */ - ugeth->tx_skbuff[txQ][ugeth->skb_curtx[txQ]] = skb; + txInd = ugeth->skb_curtx[txQ]; + ugeth->tx_skbuff[txQ][txInd] = skb; /* Update the current skb pointer (wrapping if this was the last) */ - ugeth->skb_curtx[txQ] = - (ugeth->skb_curtx[txQ] + - 1) & TX_RING_MOD_MASK(ugeth->ug_info->bdRingLenTx[txQ]); + txInd = (txInd + 1) & TX_RING_MOD_MASK(ugeth->ug_info->bdRingLenTx[txQ]); + ugeth->skb_curtx[txQ] = txInd; /* set up the buffer descriptor */ out_be32(&((struct qe_bd __iomem *)bd)->buf, @@ -3088,9 +3089,8 @@ static int ucc_geth_start_xmit(struct sk_buff *skb, struct net_device *dev) /* If the next BD still needs to be cleaned up, then the bds are full. We need to tell the kernel to stop sending us stuff. */ - if (bd == ugeth->confBd[txQ]) { - if (!netif_queue_stopped(dev)) - netif_stop_queue(dev); + if (!in_be32((u32 __iomem *)(bd+4))) { + netif_stop_queue(dev); } ugeth->txBd[txQ] = bd; @@ -3198,32 +3198,29 @@ static int ucc_geth_tx(struct net_device *dev, u8 txQ) struct ucc_geth_private *ugeth = netdev_priv(dev); u8 __iomem *bd; /* BD pointer */ u32 bd_status; + int txInd, num_freed; bd = ugeth->confBd[txQ]; bd_status = in_be32((u32 __iomem *)bd); - + txInd = ugeth->skb_dirtytx[txQ]; + num_freed = 0; /* Normal processing. */ while ((bd_status & T_R) == 0) { /* BD contains already transmitted buffer. */ /* Handle the transmitted buffer and release */ /* the BD to be used with the current frame */ - if ((bd == ugeth->txBd[txQ]) && (netif_queue_stopped(dev) == 0)) - break; + if (!in_be32((u32 __iomem *)(bd+4))) + break; /* Queue is empty */ dev->stats.tx_packets++; /* Free the sk buffer associated with this TxBD */ - dev_kfree_skb(ugeth-> - tx_skbuff[txQ][ugeth->skb_dirtytx[txQ]]); - ugeth->tx_skbuff[txQ][ugeth->skb_dirtytx[txQ]] = NULL; - ugeth->skb_dirtytx[txQ] = - (ugeth->skb_dirtytx[txQ] + - 1) & TX_RING_MOD_MASK(ugeth->ug_info->bdRingLenTx[txQ]); - - /* We freed a buffer, so now we can restart transmission */ - if (netif_queue_stopped(dev)) - netif_wake_queue(dev); + dev_kfree_skb(ugeth->tx_skbuff[txQ][txInd]); + ugeth->tx_skbuff[txQ][txInd] = NULL; + out_be32((u32 __iomem *)(bd+4), (int)NULL); /* Mark it free */ + num_freed++; + txInd = (txInd + 1) & TX_RING_MOD_MASK(ugeth->ug_info->bdRingLenTx[txQ]); /* Advance the confirmation BD pointer */ if (!(bd_status & T_W)) @@ -3233,6 +3230,9 @@ static int ucc_geth_tx(struct net_device *dev, u8 txQ) bd_status = in_be32((u32 __iomem *)bd); } ugeth->confBd[txQ] = bd; + ugeth->skb_dirtytx[txQ] = txInd; + if (num_freed) + netif_wake_queue(dev); /* We freed some buffers, so restart transmission */ return 0; }
The line: if ((bd == ugeth->txBd[txQ]) && (netif_queue_stopped(dev) == 0)) break; in ucc_geth_tx() didn not make sense to me. Rework & cleanup this logic to something understandable. Signed-off-by: Joakim Tjernlund <Joakim.Tjernlund@transmode.se> --- drivers/net/ucc_geth.c | 40 ++++++++++++++++++++-------------------- 1 files changed, 20 insertions(+), 20 deletions(-)