IBM pSeries - Manual (Page 24)

pshpstuningguidewp040105.doc Page 24
MPCI: sends = 14
MPCI: sendsComplete = 14
MPCI: sendWaitsComplete = 17
MPCI: recvs = 17
MPCI: recvWaitsComplete = 13
MPCI: earlyArrivals = 5
MPCI: earlyArrivalsMatched = 5
MPCI: lateArrivals = 8
MPCI: shoves = 10
MPCI: pulls = 13
MPCI: threadedLockYields = 0
MPCI: unorderedMsgs = 0
LAPI: Tot_dup_pkt_cnt=0
LAPI: Tot_retrans_pkt_cnt=0
LAPI: Tot_gho_pkt_cnt=0
LAPI: Tot_pkt_sent_cnt=14
LAPI: Tot_pkt_recv_cnt=15
LAPI: Tot_data_sent=4194
LAPI: Tot_data_recv=3511
5.12 Dropped switch packets
Lower than expected performance can be caused by dropped packets on the HPS switch. Packets
sent over a switch interface can be dropped in several ways, as described in the following
sections.
5.12.1 Packets dropped because of a software problem on an
endpoint
Packets are sometimes dropped at one of the endpoints of the packet transfer. In this case, you
should be able to run AIX 5L commands to see some evidence on the endpoint that dropped the
packet. For example, run
/usr/sni/sni.snap -l {adapter_number} to get the
correct endpoint data. This is best taken both before and after re-creating the problem. The
sni.snap creates a new archive in /var/adm/sni/snaps. For example,
/usr/sni/sni.snap -
l 1 produces a hostname.adapter_no.timestamp file such as
/var/adm/sni/snaps/c704f2n01.1.041118122825.FEFE5.sni.snap.tar.Z.
For IP traffic, looking at netstat -D data is a good place to start:
netstat -D
Source Ipkts Opkts Idrops Odrops
[. . .]
sn_dmx0 156495 N/A 0 N/A
sn_dmx1 243602 N/A 0 N/A
sn_if0 156495 140693 0 0
sn_if1 243602 241028 0 13
ml_if0 0 98 0 10
The ifsn_dump command provides interface-layer statistics for the sni interfaces. This tool helps
you diagnose packet drops seen in netstat -D and also prints some drops that are not shown under
netstat.