Subject: Re: Measuring dropped packets
To: None <tech-net@netbsd.org>
From: Christoph Kaegi <kgc@zhwin.ch>
List: tech-net
Date: 10/26/2006 16:19:16
On 26.10-15:14, Manuel Bouyer wrote:
> You can also look at netstat -q, to see if there are drops at a highter
> level. If you see drops here you can try to bump IFQ_MAXLEN
> to something larger than 256.

---------------------------- 8< ----------------------------
# netstat -q
arpintrq:
        queue length: 0
        maximum queue length: 50
        packets dropped: 826
ipintrq:
        queue length: 0
        maximum queue length: 256
        packets dropped: 91897332
---------------------------- 8< ----------------------------

Ugh! Seems like a lot of dropped packets on the last line.
Can you explain, where exactly that these packets were
dropped?

> 
> Also look at vmstat -m, especially for failed requests to mbpl and mclpl.
> If there are failed requests you have to bump NMBCLUSTERS (you'll have to
> if you bump IFQ_MAXLEN anyway, I think)

---------------------------- 8< ----------------------------
intfw (primary)# vmstat -m
vmstat: Kmem statistics are not being gathered by the kernel.
Memory resource pool statistics
Name        Size Requests Fail Releases Pgreq Pgrel Npage Hiwat Minpg Maxpg Idle
mbpl         256     3436    0        0   216     0   216   216     1   inf    1
mclpl       2048     1501    0        0   755     0   755   755     4  1024    4
---------------------------- 8< ----------------------------

> 
> You may also want to install something like pkgsrc/net/mrtg, to
> monitor traffic, in both byte count and packets counts (the script provided
> in the above package does byte count, but it's trivial to change it to
> do packets count too)
> 

I'm running nload at the moment which says for the outer interface:
---------------------------- 8< ----------------------------
Incoming:                                      Outgoing:
Curr: 11.92 MBit/s                             Curr: 3.34 MBit/s
Avg: 11.67 MBit/s                              Avg: 6.67 MBit/s
Min: 0.00 MBit/s                               Min: 0.90 MBit/s
Max: 61.23 MBit/s                              Max: 44.10 MBit/s
---------------------------- 8< ----------------------------

I'm going to look at where to bump IFQ_MAXLEN now...

Thanks and until later

Chris

-- 
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Christoph Kaegi                                           kgc@zhwin.ch
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