Yes, shared memory is often not considered, because it can be used by many process - or it is counted several times.
A special type of shared memory is the SysV IPC (inter process communication), listed with
E.g. for the "Shared Memory" the listed PIDs are for the "Creator" and the "Last attacher".
Even the normal fork/exec to create a new process produces shared memory.
Because initially they are identical, they are not actually copied but the new process reuses the memory. They are really copied when the new process modifies it. This is called COW (copy on write).
Your last sentence is the explanation of why two identical servers have different usage of memory? To be honest i tried to read man page of ipcs. I can give you the output of those 2 servers... but i still cannot understand it....
I am about to give it up..
My next shot is to reboot the server which confuses me and check its reaction...
But i would like to have any "evidence" to approve the need of reboot!
Hi All,
I have a question, can you guys please help me by giving your valuable suggestons:
I am using AIX 5L, running oracle 7 version. I need to increase the oracle memory to 40 MB more. Currently Oracle occupies 260M. I wanted to know whether I can increase the memory without any problem.... (1 Reply)
Hi All,
I have a question, can you guys please help me by giving your valuable suggestons:
I am using AIX 5L, running oracle 7 version. I need to increase the oracle memory to 40 MB more. Currently Oracle occupies 260M. I wanted to know whether I can increase the memory without any problem.... (3 Replies)
Hi,
We have AIX 5.1 machine of RAM 8 GB and paging space is 8GB. we are getting high memory usage of almost 99%.Can anybody please help in this ?
Partial vmstat o/p
kthr memory
----- -----------
r b avm fre
2 1 278727 1143
There is no paging issue.Becoz in... (5 Replies)
Hi Guys,
I wonder what would be the best way to determine how much memory is in use on any given time by the database processes. I thought about using ipcs -m command but I wonder if there any better way to determine this. Thanks.
Harby. (2 Replies)
Hi,
I have AIX 5.3TL8 two node cluster using HACMP and have 10g database using RAW devices. I am seeing gradual increase in comp% memory everyday and it reaches 100% and evicts the node, we had 4 evictions in 40days.
I am pasting vmstat and vmo output, anyone seen this issue?
... (5 Replies)
Hi All,
Anyone has script to monitor AIX total processes memory and cpu usage that contribute to the total memory and CPU utilize so far ?
The purpose of this is to analyze process memory trend.
Thanks.
Best Regards,
ckwan (2 Replies)
Hi All,
I have some questions regarding the performance, MEMORY/ Virtual Memory (paging /swap space)
Please see the nmon-MEMORY stats from my AIX LPAR.
24 GB --> RAM
3456 MB --> Paging Space
│ Memory ───────────────────────────────────────────────────────────────────────
│... (8 Replies)
Discussion started by: System Admin 77
8 Replies
LEARN ABOUT HPUX
serialize
serialize(2) System Calls Manual serialize(2)NAME
serialize() - force target process to run serially with other processes
SYNOPSIS DESCRIPTION
The system call is used to force the target process referenced by the pid value passed in to run serially with other processes also marked
for serialization. If the value of pid is zero, then the currently running process is marked for serialization. Once a process has been
marked by the process stays marked until process completion, unless is reissued on the serialized process with timeshare set to 1. If
timeshare is set to 1, the process specified in pid will be returned to normal timeshare scheduling algorithms.
This call is used to improve process throughput since process throughput usually increases for large processes when they are executed seri-
ally instead of allowing each program to run for only a short period of time. By running large processes one at a time, the system makes
more efficient use of the CPU as well as system memory, since each process does not end up constantly faulting in its working set, to only
have the pages stolen when another process starts running. As long as there is enough memory in the system, processes marked by behave no
differently from other processes in the system. However, once memory becomes tight, processes marked by are run one at a time with the
highest priority processes being run first. Each process runs for a finite interval of time before another serialized process is allowed
to run.
RETURN VALUE
returns zero upon successful completion, or nonzero if the system call failed.
ERRORS
If fails, it sets (see errno(2)) to the following value:
The pid passed in does not exist.
WARNINGS
The user has no way of forcing an execution order on serialized processes.
AUTHOR
was developed by HP.
SEE ALSO serialize(1), privileges(5).
serialize(2)