another shared memory question.

[Simon Jespersen]

Hi! We are working on a applikation issues and there is something about shared memory i dont understand.

We have allocated 1 gb. to shmmax
Parameter: shmmax
Current: 1073741824
Planned: 1073741824
Default: 0X4000000
Minimum: -
Module: -
Version: -
Dynamic: Yes

Parameter: shmmni
Current: 1024
Planned: 1024
Default: 200
Minimum: -
Module: -
Version: -
Dynamic: No

Parameter: shmseg
Current: 1024
Planned: 1024
Default: 120
Minimum: -
Standard input

When i do a ipcs -mb and count up the shared memory in use i see that it exseeds the 1 gb.
How do that work. Are there something about shared emory i dont understand, i thought that when you set 1 gb in shmmax i could not allocate more, that is, OS it self, applikation oracle etc..

here is the output for ipcs -mb
root@pello:./root $ ipcs -mb
IPC status from /dev/kmem as of Tue Jan 31 10:18:53 2006
T ID KEY MODE OWNER GROUP SEGSZ
Shared Memory:
m 3072 0x411c0262 --rw-rw-rw- root sys 348
m 1 0x00000000 D-rw-rw-rw- root root 61760
m 5122 0x4e0c0002 --rw-rw-rw- root sys 61760
m 3 0xdeadbeef --rw-rw-rw- root root 237420
m 13316 0x0c6629c9 --rw-r----- root root 22686824
m 5 0x06347849 --rw-rw-rw- root root 77384
m 2054 0x4918110c --rw-r--r-- root root 22908
m 43015 0x5e100005 --rw------- root root 512
m 1032 0x00000000 --rw-r----- oracle dba 1073741824
m 9 0x07a91574 --rw-r----- oracle dba 1019904
m 3082 0x41545200 --rw-rw-rw- maestro unison 1048576
m 1035 0x4154520b --rw-rw-rw- maestro unison 524288
m 12 0x4154520f --rw-rw-rw- maestro unison 1048576
m 3085 0x4154520a --rw-rw-rw- maestro unison 1048576
m 14 0x4154520c --rw-rw-rw- maestro unison 1048576
m 15 0x4154520d --rw-rw-rw- maestro unison 1048576
m 16 0x4154520e --rw-rw-rw- root unison 1048576
m 17 0x00000000 D-rw------- tdcmme mme 57368
m 77842 0x00000000 --rw-r--r-- tdcmme mme 34773
m 76819 0x00000000 --rw-r--r-- tdcmme mme 68956
m 10260 0x00000000 --rw-r--r-- tdcmme mme 48682
m 4117 0x41205490 --rw-rw-rw- root sys 8192
m 6166 0x41205470 --rw-rw-rw- root sys 1024
m 6167 0x4e1c3946 --rw-rw-rw- root sys 108
m 12312 0x00000000 --rw-r--r-- tdcmme mme 12
m 2073 0x00000000 --rw-r--r-- tdcmme mme 4644
m 33818 0x00000000 --rw-r--r-- tdcmme mme 1889
m 33819 0x00000000 --rw-r--r-- tdcmme mme 2604
m 43036 0x00000000 --rw-r--r-- tdcmme mme 12
m 8221 0x00000000 --rw-r--r-- tdcmme mme 63842
m 17438 0x00000000 --rw-r--r-- tdcmme mme 40641
m 17439 0x00000000 --rw-r--r-- tdcmme mme 43324
m 17440 0x00000000 --rw-r--r-- tdcmme mme 12
m 6177 0x00000000 --rw-r--r-- tdcmme mme 8784
m 2082 0x00000000 --rw-r--r-- tdcmme mme 365
m 6179 0x00000000 --rw-r--r-- tdcmme mme 10924
m 6180 0x00000000 --rw-r--r-- tdcmme mme 12
m 2085 0x00000000 --rw-r--r-- tdcmme mme 980
m 74790 0x00000000 --rw-r--r-- tdcmme mme 214831360
m 74791 0x00000000 --rw-r--r-- tdcmme mme 288744600
m 2088 0x00000000 --rw-r--r-- tdcmme mme 12
m 74793 0x00000000 --rw-r--r-- tdcmme mme 12
m 6186 0x00000000 --rw-r--r-- tdcmme mme 2141
m 6187 0x00000000 --rw-r--r-- tdcmme mme 2020
m 6188 0x00000000 --rw-r--r-- tdcmme mme 12
m 6189 0x00000000 --rw-r--r-- tdcmme mme 32967
m 15406 0x00000000 --rw-r--r-- tdcmme mme 3304
m 6191 0x00000000 --rw-r--r-- tdcmme mme 47933
m 6192 0x00000000 --rw-r--r-- tdcmme mme 51780
m 6193 0x00000000 --rw-r--r-- tdcmme mme 12
m 15410 0x00000000 --rw-r--r-- tdcmme mme 4800
m 15411 0x00000000 --rw-r--r-- tdcmme mme 12
m 6196 0x00000000 --rw-r--r-- tdcmme mme 39368
m 6197 0x00000000 --rw-r--r-- tdcmme mme 5973
m 6198 0x00000000 --rw-r--r-- tdcmme mme 11128
m 6201 0x00000000 --rw-r--r-- tdcmme mme 12
m 6202 0x00000000 --rw-r--r-- tdcmme mme 16731
m 6203 0x00000000 --rw-r--r-- tdcmme mme 28924
m 6204 0x00000000 --rw-r--r-- tdcmme mme 12
m 2109 0x00000000 --rw-r--r-- tdcmme mme 821
m 2110 0x00000000 --rw-r--r-- tdcmme mme 2064
m 2111 0x00000000 --rw-r--r-- tdcmme mme 12
m 6208 0x00000000 --rw-r--r-- tdcmme mme 3482
m 6209 0x00000000 --rw-r--r-- tdcmme mme 1364
m 6210 0x00000000 --rw-r--r-- tdcmme mme 12
m 31811 0x00000000 --rw-r--r-- tdcmme mme 357
m 31812 0x00000000 --rw-r--r-- tdcmme mme 672
m 30789 0x00000000 --rw-r--r-- tdcmme mme 12
m 6214 0x00000000 --rw-r--r-- tdcmme mme 3843
m 6215 0x00000000 --rw-r--r-- tdcmme mme 8224
m 6216 0x00000000 --rw-r--r-- tdcmme mme 12
m 6217 0x00000000 --rw-r--r-- tdcmme mme 774
m 6218 0x00000000 --rw-r--r-- tdcmme mme 1764
m 6219 0x00000000 --rw-r--r-- tdcmme mme 12
m 6220 0x00000000 --rw-r--r-- tdcmme mme 9958
m 6221 0x00000000 --rw-r--r-- tdcmme mme 3032
m 6222 0x00000000 --rw-r--r-- tdcmme mme 12
m 959568 0x001c0261 --rw-rw-rw- root sys 131072
m 6225 0x00000000 --rw-r--r-- tdcmme mme 2423
m 35922 0x011c0261 --rw-rw-rw- root sys 131072
m 40019 0x00000000 --rw-r--r-- tdcmme mme 66768
m 15444 0x00000000 --rw-r--r-- tdcmme mme 6393
m 15445 0x00000000 --rw-r--r-- tdcmme mme 9636
m 15446 0x00000000 --rw-r--r-- tdcmme mme 12
m 7255 0x00000000 --rw-r--r-- tdcmme mme 3197
m 34904 0x00000000 --rw-r--r-- tdcmme mme 12
m 48217 0x00000000 --rw-r--r-- tdcmme mme 37
m 11354 0x00000000 --rw-r--r-- tdcmme mme 100
m 16475 0x00000000 --rw-r--r-- tdcmme mme 12
m 10332 0x00000000 --rw-r--r-- tdcmme mme 38
m 10333 0x00000000 --rw-r--r-- tdcmme mme 80
m 74846 0x00000000 --rw-r--r-- tdcmme mme 12
m 6239 0x00000000 --rw-r--r-- tdcmme mme 6224930
m 6240 0x00000000 --rw-r--r-- tdcmme mme 6225432
m 6241 0x00000000 --rw-r--r-- tdcmme mme 12
m 9314 0x00000000 --rw-r--r-- tdcmme mme 42
m 36963 0x00000000 --rw-r--r-- tdcmme mme 40
m 7268 0x00000000 --rw-r--r-- tdcmme mme 12
m 9317 0x00000000 --rw-r--r-- tdcmme mme 2217
m 7270 0x00000000 --rw-r--r-- tdcmme mme 738
m 36967 0x00000000 --rw-r--r-- tdcmme mme 2660
m 26728 0x00000000 --rw-r--r-- tdcmme mme 97628
m 27753 0x00000000 --rw-r--r-- tdcmme mme 151712
m 15466 0x00000000 --rw-r--r-- tdcmme mme 12
m 15467 0x00000000 --rw-r--r-- tdcmme mme 3564
m 26732 0x00000000 --rw-r--r-- tdcmme mme 12
m 15469 0x00000000 --rw-r--r-- tdcmme mme 7628
m 15470 0x00000000 --rw-r--r-- tdcmme mme 12
m 25711 0x00000000 --rw-r--r-- tdcmme mme 92541
m 25712 0x00000000 --rw-r--r-- tdcmme mme 61540
m 27761 0x00000000 --rw-r--r-- tdcmme mme 12
m 22642 0x00000000 --rw-r--r-- tdcmme mme 146883
m 13427 0x00000000 --rw-r--r-- tdcmme mme 67294
m 21620 0x00000000 --rw-r--r-- tdcmme mme 236472
m 2165 0x00000000 --rw-r--r-- tdcmme mme 34
m 2166 0x00000000 --rw-r--r-- tdcmme mme 40
m 2167 0x00000000 --rw-r--r-- tdcmme mme 12
m 2168 0x00000000 --rw-r--r-- tdcmme mme 34
m 2169 0x00000000 --rw-r--r-- tdcmme mme 40
m 2170 0x00000000 --rw-r--r-- tdcmme mme 12
m 5243 0x00000000 --rw-r--r-- tdcmme mme 12
m 5244 0x00000000 --rw-r--r-- tdcmme mme 131104
m 5245 0x00000000 --rw-r--r-- tdcmme mme 12
m 5246 0x00000000 --rw-r--r-- tdcmme mme 44416
m 5247 0x00000000 --rw-r--r-- tdcmme mme 12
m 5248 0x00000000 --rw-r--r-- tdcmme mme 44416
m 65665 0x00000000 --rw-r--r-- tdcmme mme 12
m 66690 0x00000000 --rw-r--r-- tdcmme mme 68596
m 35971 0x00000000 --rw-r--r-- tdcmme mme 12
m 6276 0x00000000 --rw-r--r-- tdcmme mme 1072
m 5253 0x00000000 --rw-r--r-- tdcmme mme 12
m 6278 0x00000000 --rw-r--r-- tdcmme mme 6652
m 45191 0x00000000 --rw-r--r-- tdcmme mme 12
m 41096 0x00000000 --rw-r--r-- tdcmme mme 1692
m 39049 0x00000000 --rw-r--r-- tdcmme mme 12
root@pello:./root $


Im running hpux 11.11 on rp4440 PA-RISC

[Hemmetter]

Hi Simon,

from ipcs(1)

<...>
WARNINGS
ipcs produces only an approximate indication of actual system status because system processes are continually changing while ipcs is acquiring the requested information.

Do not rely on the exact field widths and spacing of the output, as these will vary depending on the system, the release of HP-UX, and the data to be displayed.


rgds
HGH

[Brian Sealey]

Hi Simon,

As I understand it, and apologies if this is wrong as I'm fairly new to HP-UX, but shmmax is the maximum amount a single process can ask for, not an overall system limit.

HTH,

Brian.

[Zeev Schultz]

works like that:

in 32bit system each process is limited to 1.75gb of shared mem, you can get is higher to 2.75gb by setting magic number setting.

This is per process.

Shmmax is system wide parameter and refers to shared memory segment size.shmmax is usually limited by segment size,which is 1gb in 32bit systems and over 1gb for 64bit applications on 64bit systems.

To sum up: shmmax limits shared memory segment size but obviously that it doesn't mean total ammount of shared memory :)

See here for semantics :
http://docs.hp.com/en/939/KCParms/KCparam.ShMmax.html

[Simon Wickham_6]

Hi Simon,

shminfo will show you the addresses of all the shared memory segments.

To see usage:
# ipcs -bmop

Regards,
Simon

[Javier Noriega]

Hi group,

I see there are segments they have been removed; will it be the diference of size ?


m 17 0x00000000 D-rw------- tdcmme mme 57368
m 1 0x00000000 D-rw-rw-rw- root root 61760

Regards.

[Steve Steel]

Hi

Memory Usage (What is using all of the memory?)

Full document is at external ftp site: ftp://eh:spear9@hprc.external.hp.com/memory.htm

This is the best source of info I know

Steve Steel