[PATCH] NFS Server performance and 8139too

[PATCH] NFS Server performance and 8139too

[Oleg Makarenko]

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Since 2.2.19 I have a very poor NFS server performance on Linux 
using 8139too driver (v0.9.14) while the driver v0.9.10 from 2.2.18 
works fine (even with 2.2.19)

I have checked 2.2.20pre2 and 8139too project pages and found no patches
for the problem. Am I alone with that bad NFS performance here?

My setup:

PII-500, 196M, Linux 2.2.19. rh6.2, 8139too, 
serves as NFS server and client for SCO OpenServer and file server and
client
for macintosh

the following command on SCO:

sco# cat /mnt/linux/one-megabyte-file > /dev/null 

takes about 30 minutes with 2.2.19 kernel and about 0.3 secs on 2.2.18.
(I have never made the real benchmarks, numbers are just to show the 
difference)

The following one line patch puts performance of 2.2.19 back to
2.2.18 for me and I use it for a week without any problems.

Beware that I am not a kernel hacker so the patch can be completely 
wrong. But I hope it still can provide some useful information to 
somebody  who really knows what is going on here :)

oleg

[-- Attachment #2: linux-2.2.19-8139too.patch --]
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--- linux-2.2.19/drivers/net/8139too.c	Sun Mar 25 20:37:34 2001
+++ linux-mole/drivers/net/8139too.c	Sat May 12 18:27:48 2001
@@ -1808,6 +1808,7 @@
 		tp->dirty_tx = dirty_tx;
 		if (netif_queue_stopped (dev))
 			netif_wake_queue (dev);
+		mark_bh(NET_BH);
 	}
 }

netif_wake_queue wrong was Re: [PATCH] NFS Server performance and 8139too

[Andi Kleen]

On Sun, May 13, 2001 at 11:32:00AM +0400, Oleg Makarenko wrote:
> Beware that I am not a kernel hacker so the patch can be completely 
> wrong. But I hope it still can provide some useful information to 
> somebody  who really knows what is going on here :)

The problem is that the netif_wake_queue() 2.4 compatibility macro that
was recently added to 2.2 was wrong. It should do a mark_bh(). 8139too
uses the 2.4 macros, and therefore the netbh was always scheduled for too
late and performance was bad.

This patch should fix all drivers that use the new framework.


--- linux/include/linux/kcomp.h	Tue Dec 19 17:57:30 2000
+++ linux-work/include/linux/kcomp.h	Sun May 13 13:01:11 2001
@@ -17,7 +17,7 @@
 
 #define	net_device			device
 #define dev_kfree_skb_irq(a)		dev_kfree_skb(a)
-#define netif_wake_queue(dev)		clear_bit(0, &dev->tbusy)
+#define netif_wake_queue(dev)		do { clear_bit(0, &dev->tbusy); mark_bh(NET_BH); } while(0)
 #define netif_stop_queue(dev)		set_bit(0, &dev->tbusy)
 #define netif_start_queue(dev)		do { dev->tbusy = 0; dev->interrupt = 0; dev->start = 1; } while (0)
 #define netif_queue_stopped(dev)	dev->tbusy



-Andi

Re: netif_wake_queue wrong was: [PATCH] NFS Server performance and 8139too

[Oleg Makarenko]

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Andi Kleen wrote:
> 
> On Sun, May 13, 2001 at 11:32:00AM +0400, Oleg Makarenko wrote:
> > Beware that I am not a kernel hacker so the patch can be completely
> > wrong. But I hope it still can provide some useful information to
> > somebody  who really knows what is going on here :)
> 
> The problem is that the netif_wake_queue() 2.4 compatibility macro that
> was recently added to 2.2 was wrong. It should do a mark_bh(). 8139too
> uses the 2.4 macros, and therefore the netbh was always scheduled for too
> late and performance was bad.
> 
> This patch should fix all drivers that use the new framework.
> 

Unfortunately it doesn't. 8139too (and every other driver in 2.2.19 
source tree) uses its own version of netif_wake_queue(). So your patch
doesn't solve the problem with 8139too.

Here is another patch for 8139too that places mark_bh() into the 
netif_wake_queue() macro definition in 8139too.c. 

Or with you patch for kcomp.h is it now better to completely remove 
the macro redefinition from 8139too.c?

My first patch is more of reverse type as it places mark_bh() 
(that was lost) right after the netif_wake_queue() and 
calls mark_bh() more often than it wakes the queue in a manner 
of the older (working) 8139too version.

oleg

[-- Attachment #2: linux-2.2.19-8139too.patch --]
[-- Type: application/octet-stream, Size: 471 bytes --]

--- linux-2.2.20pre2/drivers/net/8139too.c	Mon May 14 11:16:30 2001
+++ linux-mole/drivers/net/8139too.c	Mon May 14 11:17:22 2001
@@ -187,7 +187,7 @@
 #endif
 
 #define dev_kfree_skb_irq(a)	dev_kfree_skb(a)
-#define netif_wake_queue(dev)	clear_bit(0, &dev->tbusy)
+#define netif_wake_queue(dev)	do { clear_bit(0, &dev->tbusy) ; mark_bh(NET_BH); } while(0)
 #define netif_stop_queue(dev)	set_bit(0, &dev->tbusy)
 
 static inline void netif_start_queue(struct device *dev)