mbuf usage for an idle machine

Giovanni P. Tirloni gpt at tirloni.org
Tue Aug 26 20:03:19 PDT 2003


Hi,

 I've been reading about mbufs and how they're used for
 holding network packets and socket buffers and the 
 output of 'netstat -m' for a idle machine I've here 
 made me curious about how FreeBSD handles it in -CURRENT.

 Why is it using so many mbufs when it's idle? My
 small kwnowledge doesn't permit me to answer this
 question yet ;) 

 root at gate:~# netstat -m
 mbuf usage:
         GEN cache:      0/0 (in use/in pool)
         CPU #0 cache:   130/288 (in use/in pool)
         Total:          130/288 (in use/in pool)
         Mbuf cache high watermark: 512
         Maximum possible: 9856
         Allocated mbuf types:
           130 mbufs allocated to data
         2% of mbuf map consumed
 mbuf cluster usage:
         GEN cache:      0/8 (in use/in pool)
         CPU #0 cache:   128/256 (in use/in pool)
         Total:          128/264 (in use/in pool)
         Cluster cache high watermark: 128
         Maximum possible: 4928
         5% of cluster map consumed
 600 KBytes of wired memory reserved (48% in use)
 0 requests for memory denied
 0 requests for memory delayed
 0 calls to protocol drain routines

 root at gate:~# sockstat -4c
 USER     COMMAND    PID   FD PROTO  LOCAL ADDRESS         FOREIGN ADDRESS
 bs2      sshd       2085  4  tcp4   192.168.200.1:22      200.200.200.200:1405
 root     sshd       2082  4  tcp4   192.168.200.1:22      200.200.200.200:1405

 root at gate:~# sockstat -4l
 USER     COMMAND    PID   FD PROTO  LOCAL ADDRESS         FOREIGN ADDRESS
 root     mpd        635   14 tcp4   192.168.200.1:1723    *:*
 nobody   squid      614   4  udp4   *:49184               *:*
 nobody   squid      614   20 tcp4   127.0.0.1:3128        *:*
 root     dhcpd      469   6  udp4   *:67                  *:*
 root     sendmail   432   3  tcp4   127.0.0.1:25          *:*
 root     sshd       426   3  tcp4   *:22                  *:*
 root     ntpd       407   4  udp4   *:123                 *:*
 root     ntpd       407   5  udp4   192.168.0.254:123     *:*
 root     ntpd       407   6  udp4   192.168.200.1:123     *:*
 root     ntpd       407   7  udp4   127.0.0.1:123         *:*
 bind     named      292   4  udp4   *:49152               *:*
 bind     named      292   20 udp4   192.168.0.254:53      *:*
 bind     named      292   21 tcp4   192.168.0.254:53      *:*
 bind     named      292   22 udp4   127.0.0.1:53          *:*
 bind     named      292   23 tcp4   127.0.0.1:53          *:*

 FreeBSD gate 5.1-CURRENT FreeBSD 5.1-CURRENT #4: Wed Jul 23 \
  11:22:55 BRT 2003     root at gate:/usr/src/sys/i386/compile/ \
  GATE  i386

 It has 2 ethernet interfaces (192.168.200.1 and 192.168.0.254)

 I'll be happy to provide any additional information if it's
 needed. 

 --
 Giovanni P. Tirloni
 http://www.tirloni.org


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