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Date: Sun, 9 Sep 2007 17:33:12 +0200
From: Francois Romieu <romieu@...zoreil.com>
To: David Madsen <david.madsen@...il.com>
Cc: netdev@...r.kernel.org
Subject: Re: r8169: slow samba performance
David Madsen <david.madsen@...il.com> :
> >Does "acceptable" mean that there is a noticeable difference when compared
> >to the patch based on a busy-waiting loop ?
>
> I noticed a somewhat significant difference between patch #0002 and a
> busy wait loop with ndelay(10). Write performance was equivalent in
> both cases as should be the case. Read perfomance for me maxed out
Do you have some (gross) figure for the write performance ?
> around 150ish megabit whereas switching to the ndelay(10) loop brought
> up average performance around 350ish megabit while reading the same
> files over samba.
Hardly extatic. :o/
Do you see a difference in the system load too, say a few lines of 'vmstat 1' ?
Can you add the patch below on top of #0002 and see if there is some
benefit from it ?
diff --git a/drivers/net/r8169.c b/drivers/net/r8169.c
index b85ab4a..8d8fff3 100644
--- a/drivers/net/r8169.c
+++ b/drivers/net/r8169.c
@@ -2457,6 +2457,7 @@ static int rtl8169_start_xmit(struct sk_buff *skb, struct net_device *dev)
smp_wmb();
RTL_W8(TxPoll, NPQ); /* set polling bit */
+ RTL_R8(TxPoll);
if (TX_BUFFS_AVAIL(tp) < MAX_SKB_FRAGS) {
netif_stop_queue(dev);
I'd welcome if you could try the patch below on top of #0002 too:
diff --git a/drivers/net/r8169.c b/drivers/net/r8169.c
index b85ab4a..840df3b 100644
--- a/drivers/net/r8169.c
+++ b/drivers/net/r8169.c
@@ -2457,6 +2457,17 @@ static int rtl8169_start_xmit(struct sk_buff *skb, struct net_device *dev)
smp_wmb();
RTL_W8(TxPoll, NPQ); /* set polling bit */
+{
+ static unsigned int wait_max = 0;
+ unsigned i;
+
+ for (i = 0; (RTL_R8(TxPoll) & NPQ) && (i < 1000); i++)
+ ndelay(10);
+ if (i > wait_max) {
+ wait_max = i;
+ printk(KERN_INFO "%s: wait_max = %d\n", dev->name, wait_max);
+ }
+}
if (TX_BUFFS_AVAIL(tp) < MAX_SKB_FRAGS) {
netif_stop_queue(dev);
--
Ueimor
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