mbd(8) — bsd

MBD(8)                          Domain/OS BSD                           MBD(8)




NAME
     mbd - dump usage info on tcp buffer pool

SYNOPSIS
     /etc/mbd [ -f ] [ -k ]

DESCRIPTION
     The mbd command dumps usage information about the tcp memory buffer
     pools.  Usage statistics on tcp memory buffers may be obtained by using
     the -m option of the netstat command; mbd is intended for analyzing cases
     where buffers are being lost.  It scans the entire buffer pool, finding
     all the chains of in-use buffers; it then prints each chain of buffers.
     This information may help you in discovering reasons why buffers are
     being lost.

OPTIONS
     -f   Dump the free pools as well as the chains of in-use buffers.  This
          produces a lot of output.

     -k   Don't try to lock the mutex on the buffer pools before doing the
          dump.  This is useful mostly when the tcpd has crashed with the
          buffer pool mutex locked.

EXAMPLES
     A dump of the buffer pools of a basically idle tcp might look like this:

$ /etc/mbd
Offset 0x000035cc  size  1520 type 1 off   24 len 1512 refcnt 1 pool 1
Offset 0x000041cc  size  1520 type 1 off   24 len 1512 refcnt 1 pool 1
Offset 0x00003bcc  size  1520 type 1 off   24 len 1512 refcnt 1 pool 1
Offset 0x0000a7cc  size  1520 type 1 off   24 len 1512 refcnt 1 pool 1
Offset 0x00004dcc  size  1520 type 1 off   24 len 1512 refcnt 1 pool 1
Offset 0x00007dcc  size  1520 type 1 off   24 len 1512 refcnt 1 pool 1

          Here there are 6 large (1520-byte) buffers in use, all on a single
          chain.
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