Hello Managers !
We have an application with a high memory demand (~ 1.7 GB).
Our Dec 500au 4.0D (Patchkit 2 applied) is equipped with
640 MB RAM and 2.2 GB swap space, user/proc limits 2.2 GB.
Because the system freezes (as also reported a few days ago here
on the list), which occurs when only vm-page-free-reserved pages
are left, I've modified the vm-section parameters with dxkerneltuner:
vm-page-free- target 2048 appr. 16MB
swap 1664 13MB
optimal 1536 12MB
min 1024 8MB
reserved 768 6MB
(some ubc tuning also occured as recommended here on the list and in
the docs). What we observe now is that paging starts as requested at
free-target, but then very quickly the process demands the rest of the
pages so that we still get down to the reserved limit -> FREEZE.
The second effect is that if hard swapping starts, the most demanding
process is swapped out -- just the one we would keep running on the
basis of paging :-< ...
So I tried to push limits of vm-page-free-target up to several thousands
of pages to start paging long before we are at the limit. But then
a sys_check complains that our limit is at 2048 pages. I did not
found the parameter to increase this value in the docs. Is it vm_max_wired ?
Will it help to increase this value ? What else do we have to push up to keep
our process running while paging, not swapping ?
Here are some stats from top and vmstat 1:
------------------------------------------------
load averages: 0.26, 0.06, 0.03 16:10:09
57 processes: 1 running, 1 waiting, 16 sleeping, 39 idle
CPU states: 0.0% user, 0.0% nice, 0.0% system, 99.9% idle
Memory: Real: 228M/621M act/tot Virtual: 995M/2364M use/tot Free: 12M
PID USERNAME PRI NICE SIZE RES STATE TIME CPU COMMAND
21751 grabow 42 0 1738M 14M WAIT 3:55 7.60% <Kopra> shortly before freezing
22965 root 44 0 864K 335K sleep 0:10 0.90% <vmstat>
548 root 42 0 2648K 212K sleep 0:01 0.30% <pim>
21635 grabow 44 0 2640K 344K run 0:05 0.00% <top>
21 root 44 0 1624K 57K sleep 0:03 0.00% <update>
-------------------------------------------------
procs memory pages intr cpu
r w u act free wire fault cow zero react pin pout in sy cs us sy id
2 72 24 72K 1676 4797 540 0 60 256 480 0 483 417 2K 15 6 78
2 72 24 73K 1186 4797 677 0 192 14 485 0 490 23 2K 13 6 82
2 72 24 73K 922 4797 489 0 60 16 427 0 266 15 1K 6 3 90 <- before freezing
5 69 24 73K 767 4797 265 0 60 4104 205 0 194 4K 42K 5 3 92 <- after freeze
2 70 26 71K 3047 4801 376 0 193 4572 131 12 100 489 713 0 0 100
2 73 25 71K 2890 4827 383 73 91 256 127 0 124 616 715 3 4 93
2 72 24 71K 2793 4820 753 146 164 256 229 0 183 3K 922 5 6 88
2 72 24 72K 2461 4820 448 0 60 256 314 0 347 15 1K 1 3 96
3 71 24 72K 1982 4820 542 0 60 256 451 0 469 411 2K 10 7 83
2 72 24 73K 1425 4820 757 0 196 13 560 0 573 25 2K 16 6 79
2 72 24 73K 871 4820 626 0 60 1888 567 0 546 287 2K 16 8 77 <- before freezing
8 65 24 73K 767 4820 201 0 60 4040 140 0 263 29K285K 2 3 96 <- after freeze
4 69 24 73K 934 4796 406 1 252 13K 90 17 168 32K 1K 0 0 100 note the high
2 71 24 73K 1053 4794 202 7 60 2184 102 24 135 293 833 0 4 96 context switch rate!
2 70 24 71K 3088 4799 126 1 60 87 41 3 93 214 592 0 4 96
2 70 24 71K 2786 4799 398 0 58 256 197 0 310 15 1K 1 4 95
2 70 24 72K 2429 4799 583 0 58 256 435 0 353 18 1K 4 3 93
2 70 24 72K 1965 4799 570 0 186 255 381 0 474 417 2K 12 7 80
2 70 24 73K 1431 4805 578 0 58 255 520 0 526 25 2K 15 6 78
2 70 24 73K 872 4805 616 0 58 143 558 1 576 15 2K 16 7 78 <- before freezing
7 65 23 73K 767 4805 308 0 58 5562 249 0 283 28K287K 1 3 96 <- after freeze
2 69 25 71K 3039 4804 407 8 249 13K 45 2 106 32K 796 0 0 100
2 70 24 71K 2895 4810 279 0 58 256 136 0 173 59 862 1 3 96
2 70 24 72K 2446 4816 632 0 58 256 436 0 441 15 2K 4 5 91
2 70 24 72K 2063 4816 402 0 58 256 345 0 398 20 1K 8 4 88
2 70 24 73K 1512 4816 605 0 58 256 545 0 545 427 2K 16 9 76
2 70 24 73K 943 4816 746 0 190 208 556 0 576 15 2K 16 6 78 <- before freezing
-------------------------------------------------
Thanks for any help in advance !
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 Wed Sep 29 1999 - 14:23:04 NZST