pshpstuningguidewp040105.doc
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To help you isolate the exact cause of packet drops, the ifsn_dump -a command also lists the
following debug statistics. If you isolate packet drops to these statistics, you will probably need
to contact IBM support.
dbg:
| sNet_drop 0x00000000 [0]
| sRTF_drop 0x00000000 [0]
| sMbuf_drop 0x00000000 [0]
| sFifo_drop 0x00000000 [0]
| sQueue_drop 0x00000000 [0]
| rPool_drop 0x00000000 [0]
| m_reject 0x00000000 [0]
| rsvd_pool_used 0x00000000 [0]
| recv_not_ready 0x00000000 [0]
| recv_bad_flag 0x00000000 [0]
| recv_bad_type 0x00000000 [0]
| alloc_cntl_fail 0x00000000 [0]
| spkt_timeout 0x00000000 [0]
| bad_health_drop 0x00000000 [0]
| phantom_recv_intr 0x00000000 [0]
| same_thresh_cnt 0x00000000 [0]
| last_recv_thresh 0x0000000000000000 [0]
To see some packet drops (such as arpq drops), you must use the kdb ifnet structure (which is
common for many interfaces). Here is an example:
echo ifnet | kdb[ . . .]
SLOT 2 ---- IFNET INFO ----(@ 075AF098)----
name........ sn0 unit........ 00000000 mtu......... 0000FFE0
flags....... 08800843
(UP|BROADCAST|RUNNING|SIMPLEX|NOECHO|BPF|IFBUFMGT|CANTCHANGE...
[. . .]
init()...... 00000000 output().... 075AE498 start()..... 00000000
done()...... 00000000 ioctl()..... 075AE4B0 reset()..... 00000000
watchdog().. 00000000 ipackets.... 00026549 ierrors..... 00000000
opackets.... 00022778 oerrors..... 00000000 collisions.. 00000000
next........ 075AF2C8 type........ 00000038 addrlen..... 00000000
hdrlen...... 00000018 index....... 00000003
ibytes...... 0127BA9E obytes...... 0117B005 imcasts..... 00000000
omcasts..... 00000000 iqdrops..... 00000000 noproto..... 00000000
baudrate.... 00000000 arpdrops.... 00000002 ifbufminsize 00000200
devno....... 8000002300000000 chan........ 2FF38EB0 multiaddrs.. 00000000
tap()....... 00000000 tapctl...... FFFFFFFFFFFFFFFF arpres().... 00000000
arprev().... 00000000 arpinput().. 00000000 ifq_head.... 00000000
ifq_tail.... 00000000 ifq_len..... 00000000 ifq_maxlen.. 00000200
ifq_drops... 00000000 ifq_slock... 00000000 slock....... 00000000
5.12.2 Packets dropped in the ML0 interface
For ml0 drops to a destination, use the mltdd_dump -k command to determine if a valid ml0
route exists to destination:
/usr/sbin/mltdd_dump -k
The following example shows the route to ml0 destination 192.168.2.3, which is a valid and
complete ml0 route. If a route is incomplete, it is not valid.
mlr_next = 0x0000000000000000
mlr.state = 160
(COMPLETE)
