Vmstat, Pin Pgsp Virtual | IBM pSeries specification

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

pshpstuningguidewp040105.doc

Page 12