Measuring dropped packets

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                                          
kgczhwin.ch
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