Re[2]: packet drop with intel gigabit / marwell gigabit

i increased hz from 2000 to 5000, now the packet loss is decreased
from 5-6% to 0.6-0,8% !!!
huge improve!
should i increase hz more?

You can. But remember that higher HZ values spend more CPU time for task switching. So if the hardware is used for something more than only network workload you would get performance penalty in other areas. A faster CPU would be a useful option in your case (with a proper HZ increase)

It seems that this card has very small buffer size. And it's nothing you can do about that.



----- Original Message -----
From: "OxY" <oxy@xxxxxxxx>
To: "Chuck Swiger" <cswiger@xxxxxxx>
Cc: <freebsd-performance@xxxxxxxxxxx>
Sent: Saturday, March 18, 2006 2:23 PM
Subject: Re: packet drop with intel gigabit / marwell gigabit


currently i use HZ=2000
here's the output of netstat -i, -s, and vmstat -i :
(currently i am uploading on the gigabit with ftp, 3 threads)

Field root# vmstat -i
interrupt total rate
irq0: clk 27503959 1993
irq1: atkbd0 1 0
irq3: fxp0 2 0
irq7: 146 0
stray irq7 146 0
irq8: rtc 1765569 127
irq10: atapci1 2807786 203
irq11: atapci0 475039 34
irq13: npx0 1 0
irq14: ata0 99 0
Total 32552748 2359

Field root# netstat -i
Name Mtu Network Address Ipkts Ierrs Opkts Oerrs
Coll
fxp0 1500 <Link#1> 00:a0:c9:8d:79:68 13163545 0 21899372 1
0
fxp0 1500 195.38.96.64/ field 141 -
6 - -
em0 1500 <Link#2> 00:0e:0c:a2:ac:42 68644181 4 66793904 0
0
em0 1500 195.38.96.64/ field 211255811 -
- -
lo0 16384 <Link#3> 129622061 0 129622061
0 0

netstat -s is here:
http://field.hu/netstat.txt

----- Original Message -----
From: "Chuck Swiger" <cswiger@xxxxxxx>
To: "OxY" <oxy@xxxxxxxx>
Cc: <freebsd-performance@xxxxxxxxxxx>
Sent: Saturday, March 18, 2006 1:37 PM
Subject: Re: packet drop with intel gigabit / marwell gigabit


OxY wrote:
yeah, i googled these settings, but i put them back to default then!
i measured iperf performance, and it showed that the packet drop is
depending on the system load..

If you are using the normal interrupt-driven configuration, you should
look at
netstat -i, -s, and vmstat -i. If you're turning on device polling, you
ought
to retry your testing at higher HZ (try 2000 or 5000):

echo 'kern.hz="2000"' >> /boot/loader.conf

--
-Chuck

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