CPU utilization is 0% if apache is not running and 10-20%, when running and
serving 30-40 concurrent downloads (traffic is 3-4MB/s on fxp0 interface)
i measured the network performance with 'iperf' util, started the server on
my box
and benchmarked with a client on the other gigabit machine.
it showed 0% packet drop, when apache was not running and 4-7%, when
running..
then i checked how it behave when i shut down apache and init a local file
copy from one
(not system!) disk to other (not system disk either). packet drop was 5-10%,
due to the higher load.
so i think interrupts or just the load takes the network performance, but i
have no clue how to fix it.
is it possible that the 2000+ xp amd is just weak to serve such a traffic?
(em0 traffic's maximum is 18-23MB/s)
i think it might be around 30MB/s without packet drop.
I did FTP measurement, because what i want is to copy files with high speed
from the
other gigabit machine. However FTP needs resources (CPU, I/O, etc), but
iperf not!
iperf shows 20% CPU utilization when apache not running and when there's no
packet drop.
ps: Now apache says: 14 requests currently being processed
traffic is 1MB/s on fxp0, and em0 benchmark with iperf says (64k udp window
size):
[ 3] 0.0-10.0 sec 235 MBytes 197 Mbits/sec
[ 3] Sent 167375 datagrams
[ 3] Server Report:
[ 3] 0.0-10.0 sec 229 MBytes 192 Mbits/sec 0.066 ms 4115/167375
(2.5%)
the other gigabit machine is OK, because i have 0% packet drop, when my
machine is totally idle.
----- Original Message -----
From: "Jin Guojun [VFFS]" <[EMAIL PROTECTED]>
To: "OxY" <[EMAIL PROTECTED]>; "Chuck Swiger" <[EMAIL PROTECTED]>
Cc: <freebsd-performance@freebsd.org>
Sent: Sunday, March 19, 2006 1:49 AM
Subject: Re: packet drop with intel gigabit / marwell gigabit
It is still not clear how you did measurement.
Did FTP show such % drop? or Did you measure it by other tools?
How did you measured incoming traffic?
http://field.hu/netstat.txt shows 0 tcp packet drop.
Anyway, the first thing first is to have CPU utilization when you see
packet drop.
This can be get from running "top" or "vmstat 1". As well as run
netstat -i -p tcp | grep -i drop
If CPU utilization is approaching 100%, either the traffic is no 2 MBps,
or some process is taking CPU time. For this reason, "top" is a better
tool to use. At this point, if you run netstat command multiple times,
you would see drop counter increasing.
Once you find out what process takes CPU time, then further tuning can be
determined.
If CPU utilization is well below 70-80%, then you need to use tcpdump and
tcptrace to visualize what cause packet drop, then perform a solution.
Jin
----- Original Message -----
From: "OxY" <[EMAIL PROTECTED]>
To: "Chuck Swiger" <[EMAIL PROTECTED]>
Cc: <freebsd-performance@freebsd.org>
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" <[EMAIL PROTECTED]>
To: "OxY" <[EMAIL PROTECTED]>
Cc: <freebsd-performance@freebsd.org>
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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