SUMMARY: (kinda) Tuning swap/vm system parameters

From: Mohamed K. Ahmed (mkahmed@vsc.teksystems.com)
Date: Thu Jun 26 2003 - 12:31:36 EDT

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Well, thanks for the responces from Alan Davis, Selden Ball, Allan
Rollow, Brian Staab and Grant Schoep.

I am in the process now of increasing the swap space to at least double
the physical memory as recommended.
In the time being, I have changed the swap mode to lazy mode (set
vm_swap_eager to 0 ), and no problem thus far, installed top,
monitor, the /usr/local/bin/top output is around the following figures

load averages: 1.13, 0.71, 0.71
120 processes: 3 running, 47 sleeping, 69 idle, 1 zombie
CPU states: 44.9% user, 0.2% nice, 4.8% system, 49.9% idle
Memory: Real: 1170M/4506M act/tot Virtual: 5201M use/tot Free: 2725M

I will continue to monitor the system and update the list with any new
foundings.

Thenks

-Mohamed

----- Original Message -----
From: "Mohamed K. Ahmed" <mkahmed@vsc.teksystems.com>
Date: Friday, June 20, 2003 2:41 pm
Subject: Tuning swap/vm system parameters

> Hello all,
> The system is ES40, Tru64 Unix version 5.1 PK 5, 4 CPUs and 4GB
> physical memory
>
> I just have a question, why do I have always teh out put of swapon
> -s almost the same?
>
> # swapon -s
> Swap partition /dev/disk/dsk0b (default swap):
> Allocated space: 665742 pages (5.08GB)
> In-use space: 16 pages ( 0%)
> Free space: 665726 pages ( 99%) <--------- This one
>
>
> Total swap allocation:
> Allocated space: 665742 pages (5.08GB)
> Reserved space: 361349 pages ( 54%)
> In-use space: 16 pages ( 0%)
> Available space: 304393 pages ( 45%)
> #
>
> And some times when there is a lot of developers on the system,
> the Reserved swap space coes up to 90% without the 99% of Fre Space
> changing?
> Do I need to Allocate more swap or tune the vm kernel parameters?
> The sysconfig vm and proc parameters follow
> # sysconfig -q vm
> vm:
> ubc_minpercent = 10
> ubc_maxpercent = 70
> ubc_borrowpercent = 20
> vm_max_wrpgio_kluster = 32768
> vm_max_rdpgio_kluster = 16384
> vm_cowfaults = 4
> vm_segmentation = 1
> vm_ubcpagesteal = 24
> vm_ubcfilemaxdirtypages = 4294967295
> vm_ubcdirtypercent = 10
> ubc_maxdirtywrites = 5
> vm_ubcseqstartpercent = 50
> vm_ubcseqpercent = 20
> vm_csubmapsize = 1048576
> vm_ubcbuffers = 256
> vm_syncswapbuffers = 128
> vm_asyncswapbuffers = 4
> vm_clustermap = 1048576
> vm_clustersize = 65536
> vm_syswiredpercent = 80
> vm_troll_percent = 4
> vm_inswappedmin = 1
> vm_page_free_target = 2048
> vm_page_free_swap = 522
> vm_page_free_hardswap = 16384
> vm_page_free_min = 20
> vm_page_free_reserved = 10
> vm_page_free_optimal = 522
> vm_swap_eager = 1 <-----------------
> swapdevice = /dev/disk/dsk0b
> vm_page_prewrite_target = 2048
> vm_ffl = 1
> ubc_ffl = 1
> vm_rss_maxpercent = 100
> anon_rss_enforce = 0
> vm_rss_block_target = 522
> vm_rss_wakeup_target = 522
> dump_user_pte_pages = 0
> kernel_stack_pages = 0
> vm_min_kernel_address = 18446741891866165248
> malloc_percpu_cache = 1
> vm_aggressive_swap = 0 <---------
> new_wire_method = 1
> vm_segment_cache_max = 50
> gh_chunks = 0
> rad_gh_regions[0] = 0 Monostori Krisztian: "free xserver for win"