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Re: High Network Utilization?



On 12/10/2002, Park, Young K <ypark_(_at_)_ola_(_dot_)_state_(_dot_)_md_(_dot_)_us> wrote To misc_(_at_)_openbsd_(_dot_)_org:
> Even though I set NMBCLUSTERS = 32768, it still indicates that high network
> utilization(94%).

*sigh*

> olafw# netstat -m
> 324 mbufs in use:
>         321 mbufs allocated to data
>         1 mbuf allocated to packet headers
>         2 mbufs allocated to socket names and addresses
> 320/332 mapped pages in use
> 760 Kbytes allocated to network (94% in use)   <----- ????

well, it uses 94%, but that's somewhat misleading. With NMBCLUSTERS
you set 'Maxpg' of 'mclpl'. In your case to 16384 pool items, and the kernel
uses 320 items in mclpool right now; and this pool has currently a population
of 332 items (166 pages).

> olafw# vmstat -m
> Memory resource pool statistics
> Name        Size Requests Fail Releases Pgreq Pgrel Npage Hiwat Minpg Maxpg
> mbpl         256     3918    0     3573    24     0    24    24     1   inf
> 2
> mclpl       2048     2867    0     2546   166     0   166   166     4 16384
> 5

Regarding the number of Requests and Releases, I'd say, that the machine
had a rather short uptime before these commands have been issued.
Furthermore the count between mbpl and mclpl, and the mbuf type usage 
(321 mbufs allocated to data) leads me to the conclusion, that a certain
application is sending a lot of large network packets (or should receive it).

Something is wrong, since the clusters dont get freed by either sending them
to the network or getting received from the kernel to the application.

You can find this out by 'netstat -nfinet', look where big numbers for
Send-Q and/or Recv-Q appear.

After all your current pool usage would fit into the default of 2048
for NMBCLUSTERS, so dont get worried and dont touch stuff, you obviously
dont understand for now.


ciao
-- 
Philipp Buehler, aka fips | sysfive.com GmbH | BOfH | NUCH | <double-p> 

#1: Break the clue barrier!
#2: Already had buzzword confuseritis ? 



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