pshpstuningguidewp040105.doc
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PageSize Inuse Pin Pgsp Virtual
4KB 448221 3687 2675 449797
16MB 0 0 0 0
Vsid Esid Type Description LPage Inuse Pin Pgsp Virtual
1f187f 11 work text data BSS heap - 56789 0 0 56789
218a2 70000000 work default shmat/mmap - 33680 0 0 33680
131893 17 work text data BSS heap - 21840 324 0 21840
0 0 work kernel segment - 4902 3327 2563 6419
1118b1 8001000a work private load - 1405 0 0 1405
d09ad 90000000 work loader segment - 1039 0 42 1226
1611b6 90020014 work shared library text - 169 0 65 194
31823 10 clnt text data BSS heap - 145 0 - -
1a187a ffffffff work application stack - 50 0 0 50
c17ec f00000002 work process private - 31 22 0 31
b11ab 9fffffff pers shared library text, - 10 0 - -
3.3.2 vmstat
The vmstat command can show how many large pages are available for an application. It also
reports paging activity, which can indicate if thrashing is taking place. It can also be used to find
the memory footprint of an application. Unlike svmon, it does not require you to run as root.
To see a one-line summary of the vmstat statistics, enter the following command:
vmstat -l
The first part of the output reports the number of CPUs and the amount of usable physical
memory.
System Configuration: lcpu=32 mem=157696MB
kthr memory page faults cpu large-page
----- --------------------- ---------------------------- ------------------ ------------------ ------------
r b avm fre re pi po fr sr cy in sy cs us sy id wa alp flp
3 1 35953577 5188383 0 0 0 0 0 0 3334 2080 176 1 0 99 0 213 7787
The output is grouped into five categories. The last one, the large-page group, has two members:
allocated large pages (alp) and free large pages (flp). Because large pages are mapped into the
process address space in 256MB segments, the maximum number of segments an application can
get is flp * 16 / 256 . alp. This includes HPS buffers allocated in support of MPI processes on
the adapters and buffers for IP. If only one application is running on a node or LPAR, the
memory footprint of the application is the number of Active Virtual Memory (avm) pages. This
can also be measured as the difference in avm before the application was started and when it is
running. The avm is given in 4K units.
The vmstat command allows sampling at fixed intervals of time. This is done by adding an
interval in seconds to the vmstat command. For example, the following command shows vmstat
