Hello managers !
I'm observing an awkward behaviour of our processes on a 4 Processor
ES40/TruCluster5.1 PK3 (7 members). The machine has 16 GB main
memory + 22 GB virtual memory (lazy swap), and there are two
large user processes running with sizes 6.2 GB and 9.8 GB,
which leads to extensive paging.
What is awkward here is that the machine is not using
it's full physical memory, but only ~ 8 GB. The rest of
the memory is marked as inactive (pages that are likely to
be used for paging, but actually not used yet), and the needed
memory is allocated in virtual space instead, as the output
of top and vmstat shows:
=========================== top ====================================
load averages: 1.03, 0.99, 0.85 11:36:52
137 processes: 3 running, 65 waiting, 26 sleeping, 42 idle, 1 stopped
Memory: Real: 6167M/16G act/tot Virtual: 12396M/22954M use/tot Free: 15M
PID USERNAME PRI NICE SIZE RES STATE TIME CPU COMMAND
4037442 xxxx 42 19 6283M 2168M run 39:06 99.90% Rcp_0.6.22 <===
4037615 xxxx 42 0 2616K 475K sleep 0:00 4.00% tcsh
4037631 xxxx 44 0 8920K 3792K run 0:00 2.70% top
3670016 root 0 0 20G 593M run 165:37 1.40% kernel idle
4037611 root 42 0 3704K 688K sleep 0:00 1.40% sshd2
4037430 xxxx 42 19 9797M 5341M sleep 38:53 1.30% Rcp_0.6.22 <===
3671488 root 42 0 45M 4300K sleep 17:48 0.00% smsd
3670611 root 44 0 4296K 385K sleep 1:34 0.00% gated
========================= vmstat 2 ==================================
Virtual Memory Statistics: (pagesize = 8192)
procs memory pages intr cpu
r w u act free wire fault cow zero react pin pout in sy cs us sy id
6 242 171 1M 1604 98K 195M 4M 160M 37M 19M 2M 57 4K 326 45 0 55
6 242 171 1M 1683 98K 269 281 261 0 592 19 253 114 1K 25 1 74
6 242 171 1M 1611 98K 394 0 0 0 377 25 318 30 2K 25 1 74
^^^^^^
========================= vmstat -P ==================================
Total Physical Memory = 16384.00 M
= 2097152 pages
Physical Memory Clusters:
start_pfn end_pfn type size_pages / size_bytes
0 256 pal 256 / 2.00M
256 131002 os 130746 / 1021.45M
131002 131072 pal 70 / 560.00k
131072 2097122 os 1966050 / 15359.77M
2097122 2097152 pal 30 / 240.00
Physical Memory Use:
start_pfn end_pfn type size_pages / size_bytes
256 288 scavenge 32 / 256.00k
288 1136 text 848 / 6.62M
1136 1322 data 186 / 1.45M
1322 1781 bss 459 / 3.59M
1781 2012 kdebug 231 / 1.80M
2012 2018 cfgmgmt 6 / 48.00k
2018 2020 locks 2 / 16.00k
2020 2034 pmap 14 / 112.00k
2034 6296 unixtable 4262 / 33.30M
6296 6302 logs 6 / 48.00k
6302 39479 vmtables 33177 / 259.20M
39479 2097122 managed 2057643 / 16075.34M
============================
Total Physical Memory Use: 2096866 / 16381.77M
Managed Pages Break Down:
free pages = 1854
active pages = 583738
inactive pages = 1167457 <===
wired pages = 98873
ubc pages = 205681
==================
Total = 2057603
WIRED Pages Break Down:
vm wired pages = 10333
ubc wired pages = 0
meta data pages = 62852
malloc pages = 19880
contig pages = 668
user ptepages = 2021
kernel ptepages = 2185
free ptepages = 8
==================
Total = 97947
============== changes in sysconfigtab ===================
vm-swap-eager = 0
vm_segmentation = 1
vm_aggressive_swap=0
vm_page_free_target=2048
vm_page_free_swap=1664
vm_page_free_min=1024
vm_page_free_reserved=768
vm_page_free_optimal=1536
per_proc_stack_size=14000000000
max_per_proc_stack_size=14000000000
per_proc_data_size=35000000000
max_per_proc_data_size=35000000000
max_per_proc_address_space=35000000000
per_proc_address_space=35000000000
==========================================================
When starting further processes, those inactive pages remain unused,
and the machine almost stalls while paging in and out on the harddisk.
Why is the machine not using its full memory ? Is this a bug in the
memory management ?
--
Dr. Udo Grabowski email: udo.grabowski_at_imk.fzk.de
Institut f. Meteorologie und Klimaforschung II, Forschungszentrum Karslruhe
Postfach 3640, D-76021 Karlsruhe, Germany Tel: (+49) 7247 82-6026
http://www.fzk.de/imk/imk2/ame/grabowski/ Fax: " -6141
Received on Tue Sep 25 2001 - 11:34:42 NZST