i386/141314: Network Performance has decreased by 30%

[Karl Hakkinen]

>Number:         141314
>Category:       i386
>Synopsis:       Network Performance has decreased by 30%
>Confidential:   no
>Severity:       serious
>Priority:       high
>Responsible:    freebsd-i386
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Wed Dec 09 09:00:07 UTC 2009
>Closed-Date:
>Last-Modified:
>Originator:     Karl Hakkinen
>Release:        8.0
>Organization:
Nafet
>Environment:
FreeBSD theta.khakkinen.local 8.0-RELEASE FreeBSD 8.0-RELEASE #1: Sun Dec  6 23:52:44 EST 2009     karlh at theta.khakkinen.local:/usr/obj/usr/src/sys/Theta  i386
>Description:
Since installing FreeBSD 8.0 My network performance has dramatically decreased. Before I did the upgrade, I tested my network speed. After installing 8.0 (Clean install), I redid the test. The results were:

FreeBSD 7.2: 504.41 KB/s
FreeBSD 8.0: 273.17 KB/s

When I retested, the results were the same. I have also talked to other people who have upgraded to 8.0 and they say they have noticed the same problem. One of my friends who did it, noted these results on his Gigabit network:

FreeBSD 7.2: 112.5MB/s 
FreeBSD 8.0: 62.5MB/s

He is running the AMD64 version. We both tested using TTCP.
>How-To-Repeat:
Seems to be the simple act of installing FreeBSD 8.0 causes the issue.
>Fix:
The only slight patch that I found was to set the following sysctls:

net.isr.direct=0
kern.random.sys.harvest.ethernet=0
kern.random.sys.harvest.interrupt=0

It seemed to work for a few minutes, then the performance dropped to new lowers (Averaging 110 KB/s).

>Release-Note:
>Audit-Trail:
>Unformatted: