IBM pSeries

pshpstuningguidewp040105.doc Page 2
Contents
1.0 Introduction..................................................................................................... 4
2.0 Tunables and settings for switch software...................................................... 5
2.1 MPI tunables for Parallel Environment........................................................ 5
2.1.1 MP_EAGER_LIMIT .............................................................................. 5
2.1.2 MP_POLLING_INTERVAL and MP_RETRANSMIT_INTERVAL......... 5
2.1.3 MP_REXMIT_BUF_SIZE and MP_REXMIT_BUF_CNT...................... 6
2.1.4 MEMORY_AFFINITY........................................................................... 6
2.1.5 MP_TASK_AFFINITY........................................................................... 7
2.1.6 MP_CSS_INTERRUPT........................................................................ 7
2.2 MPI-IO ........................................................................................................ 7
2.3 chgsni command......................................................................................... 8
3.0 Tunables and settings for AIX 5L ................................................................... 9
3.1 IP tunables.................................................................................................. 9
3.2 File cache ................................................................................................... 9
3.3 svmon and vmstat commands .................................................................. 10
3.3.1 svmon................................................................................................. 11
3.3.2 vmstat................................................................................................. 12
3.4 Large page sizing...................................................................................... 13
3.5 Large pages and IP support...................................................................... 15
3.6 Memory affinity for a single LPAR............................................................. 15
3.7 Amount of memory available .................................................................... 15
3.8 Debug settings in the AIX 5L kernel.......................................................... 16
4.0 Daemon configuration .................................................................................. 16
4.1 RSCT daemons ........................................................................................ 16
4.2 LoadLeveler daemons .............................................................................. 17
4.2.1 Reducing the number of daemons running ........................................ 17
4.2.2 Reducing daemon communication and placing daemons on a switch17
4.2.3 Reducing logging................................................................................ 17
4.3 Settings for AIX 5L threads....................................................................... 18
4.4 AIX 5L mail, spool, and sync daemons..................................................... 18
4.5 Placement of POE managers and LoadLeveler scheduler ....................... 18
5.0 Debug settings and data collection tools...................................................... 19
5.1 lsattr tuning............................................................................................... 19
5.1.1 driver_debug setting........................................................................... 19
5.1.2 ip_trc_lvl setting.................................................................................. 19
5.2 CPUs and frequency................................................................................. 19
5.3 Affinity LPARs........................................................................................... 20
5.4 Small Real Mode Address Region on HMC GUI....................................... 20
5.5 Deconfigured L3 cache............................................................................. 20
5.6 Service focal point..................................................................................... 20
5.7 errpt command.......................................................................................... 21
5.8 HMC error logging..................................................................................... 21
5.9 Multiple versions of MPI libraries .............................................................. 21