RP/TUX 7.1 - multi-threaded server's rcv buffer re-allocation mechanism is broken... - CR034654

(Doc ID 766648.1)

Last updated on NOVEMBER 04, 2016

Applies to:

Oracle Tuxedo / Tuxedo / 7.1
Information in this document applies to any platform



Problem found in TUX 7.1 (without patch or with RP004) multi-threaded server on HPUX11 platform.

For the message size ~4.5k to 9k bytes big, the multi-threaded server's rcv buffer re-allocation mechanism is not
working.  If you do a truss (tusc for HPUX11) on the server, you will see msgrcv() repeatedly running into E2BIG
errors which cause a lot of performance penalty.  We suppose to have an internal rcv buffer re-allocation hystersis
mechanism to track/reuse the previous allocated rcv buffer to eliminate such repeated E2BIG errors.  Evidentially,
such hystersis mechanism does not kick in for message size ~4.5k to 9k bytes big.  For message size > 9kbytes seems
working OK.

Testcase located in lclab1.beasys.com:/nfs/home3/qchan/lchp12/187436/091300/simp71
- modify the perftest.c to send 5k bytes message;
- run '. ./runbuild' to rebuild everything.  Note: the key is to have 'buildserver -t' and the MAXDISPATCHTHREADS>1
in ubb.
- tmboot -y and run a (or multiple) copy of perftest
- use the tusc (Trace Unix System Call ulttlity) to get a trace on simpserv like:
../tusc/tusc -h -E -f -v -u -R -p <simpserv pid>
==> you will see msgrcv will continuously repeatedly run into E2BIG errors.
Repeat the above steps with perftest sending 10000bytes message and you will not see those E2BIG errors.


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