IBM pSeries - Manual (Page 29)

pshpstuningguidewp040105.doc Page 29
5.14 LAPI_DEBUG_COMM_TIMEOUT
If the LAPI protocol experiences communication timeouts, set the environment variable
LAPI_DEBUG_COMM_TIMEOUT to
PAUSE . This causes the application to issue a pause()
call when encountering a timeout, which stops the application instead of closing it.
5.15 LAPI_DEBUG_PERF
The LAPI_DEBUG_PERF flag is not supported and should not be used in production. However,
it can provide useful information about packet loss. If you suspect packet drops are reducing
performance, set the LAPI_DEBUG_PERF flag to
yes (export LAPI_DEBUG_PERF=yes ).
The following additional information is sent to standard error in the job output:
_retransmit_pkt_cnt
Tot_retrans_pkt_cnt
LAPI
Tot_retrans_pkt_cnt
Shared Tot_retrans_pkt_cnt
Be aware that some retransmissions in the initialization stage are normal.
Here is a simple Perl script (count_drops) to count the number of lost packets. When
LAPI_DEBUG_PERF is set to
yes , this script is run against the STDERR of an LAPI job.
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#!/usr/bin/perl
$retrans=0;
$dup=0;
$ftbl_drop=0;
$diff=0;
while ( )
{
if( /(.*)Shared Tot_dup_pkt_cnt(.*)= (.*)/) {
$dup += $3;
}
if( /(.*)Shared Tot_retrans_pkt_cnt(.*)= (.*)/) {
$retrans += $3;
}
if( /(.*)_drop_due_to_usr_ftbl_not_setup(.*)= (.*)/) {
$ftbl_drop += $3;
}
}
$diff=$retrans-$dup-$ftbl_drop;
printf "retrans=$retrans dup=$dup ftbl_drop=$ftbl_drop lost=$diff\n";
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