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upping semaphores

 
Nick Lewers
Advisor

upping semaphores

hpux 11.11

 

need to up the value of this kernel param, currently the value is at the default of 64.  From what I have read, should also consider

changing others like the ones below (screenshot from sam):

 

 

|| semmap                         66           66   Static    N/A          M   |
|| semmni                         64           64   Static    N/A          N   |
|| semmns                       8760         8760   Static    N/A          M   |
|| semmnu                       3650         3650   Static    N/A          N   |
|| semmsl                       2048         2048   Dynamic   N/A          M   |
|| semume                         64           64   Static    N/A          S   |

Some of them are configured with formulas as:

semmns          (MAXUSERS*12)
semmnu          (MAXUSERS*5)
semume          64

 

currently we are using only 60 out of 64:

 

System Table                 Available        Used      Utilization      High(%)
--------------------------------------------------------------------------------
Proc Table (nproc)               5860         2330           40           40
File Table (nfile)             328510       212074           65           65
Shared Mem Table (shmmni)         200           26           13           13
Message Table (msgmni)             50            2            4            4
Semaphore Table (semmni)           64           60           94           94
File Locks (nflocks)              500           67           13           13
Pseudo Terminals (npty)           730            0            0            0
Buffer Headers (nbuf)              na       499086           na           na

 

so really want to only double what we have (128)  as I will really only be needing a few more for a new application.   Having said that, I believe I only  need to update the following:

semmni = 128

semume = semmni

semmmap = semmni + 2

 

does that sound about right or should I take anything else under consideration?

2 REPLIES
Nick Lewers
Advisor

Re: upping semaphores

btw, forgot to add this:

#kmtune | grep sem
sema                        1  -  1
semaem                  16384  -  16384
semmap                     66  -  (SEMMNI+2)
semmni                     64  -  64
semmns                   8760  -  (MAXUSERS*12)
semmnu                   3650  -  (MAXUSERS*5)
semmsl                   2048  Y  2048
semume                     64  -  64
semvmx                  32767  -  32767

and i have no idea why semmns/semmnu are based on maxusers, seems different from other posts i have seen regarding these settings.

Dennis Handly
Acclaimed Contributor

Re: upping semaphores

>I have no idea why semmns/semmnu are based on maxusers

 

Right.  I guess it assumes the more users, the more sharing?

You may want to use a fixed size.