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5.0 Debug settings and data collection tools

Several debug settings and data collection tools can help you debug a performance problem on

systems using HPS. This section contains a subset of the most common setting changes and

tools. If a performance problem persists after you check the debug settings and the data that was

collected, call IBM service for assistance.

5.1 lsattr tuning

The lsattr command lists two trace and debug-level settings for the HPS links. The following

settings are recommended for peak performance and are the defaults.

Parameter Setting

driver_debug 0

ip_trc_lvl 0x1111

5.1.1 driver_debug setting

The driver_debug setting is used to increase the amount of information collected by the HPS

device drivers. eave this setting set to default value unless you are directed to change it by IBM

service.

5.1.2 ip_trc_lvl setting

The ip_trc_lvl setting is used to change the amount of data collected by the IP driver. Leave this

setting set to default value unless you are directed to change it by IBM service.

5.2 CPUs and frequency

Performance of parallel application can be impacted by the number of CPUs on an LPAR and by

the speed of the processors. To see how many CPUs are available and the frequency they run at,

run any of the following commands:

lsdev -Cc processor

lsattr -E -l proc#

bindprocessor -q

prtconf

pmcycles –m

If you mix slow CPUs and fast CPUs within a parallel job, the slowest CPU determines the speed

for the entire job.

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IBM pSeries User Manual Page 19