9 More Discussions You Might Find Interesting
1. Solaris
Hi Experts,
Our servers running Solaris 10 with SAP Application. The memory utilization always >90%, but the process on SAP is too less even nothing.
Why memory utilization on solaris always looks high?
I have statement about memory on solaris, is this true:
Memory in solaris is used for... (4 Replies)
Discussion started by: edydsuranta
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2. Emergency UNIX and Linux Support
Can someone please help me with a script that will help in identifying the CPU & memory usage by a process name, rather than a process id.This is to primarily analyze the consumption of resources, for performance tweaking.
G (4 Replies)
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3. UNIX for Dummies Questions & Answers
How to see the entire memory of a process in hex? (1 Reply)
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4. UNIX for Dummies Questions & Answers
Hi,
I need to monitor the memory usage of a particular process continuously. As of now I am using the following command:
ps -fu <user name> -o pid,comm,vsz | grep <process_name> | grep -v grep
The output of this command gives me what i need except i want the output to keep getting updated... (3 Replies)
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5. HP-UX
I use pstat API to get Process Infomation
I would like to get a process
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6. AIX
Hi:-
Is there an easy way to find out which process is consuming the most memory on an AIX server?
Thanks, (5 Replies)
Discussion started by: janet
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7. Shell Programming and Scripting
How do I find the amount of memory being consumed by a particular process on AIX 5L..
Thank you (0 Replies)
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8. UNIX for Dummies Questions & Answers
Hello all
'top' command shows the top 15 processes in terms of CPU usage. Is there any other command in UNIX ,that will show the top processes in terms of memory usage ? or is there a command, that will give me the memory usage of a particular process ,if I pass the process id as a... (3 Replies)
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9. UNIX for Dummies Questions & Answers
how to get memory used by a particular process in unix? (3 Replies)
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LEARN ABOUT OPENDARWIN
shm_overview
SHM_OVERVIEW(7) Linux Programmer's Manual SHM_OVERVIEW(7)
NAME
shm_overview - overview of POSIX shared memory
DESCRIPTION
The POSIX shared memory API allows processes to communicate information by sharing a region of memory.
The interfaces employed in the API are:
shm_open(3) Create and open a new object, or open an existing object. This is analogous to open(2). The call returns a file descriptor
for use by the other interfaces listed below.
ftruncate(2) Set the size of the shared memory object. (A newly created shared memory object has a length of zero.)
mmap(2) Map the shared memory object into the virtual address space of the calling process.
munmap(2) Unmap the shared memory object from the virtual address space of the calling process.
shm_unlink(3) Remove a shared memory object name.
close(2) Close the file descriptor allocated by shm_open(3) when it is no longer needed.
fstat(2) Obtain a stat structure that describes the shared memory object. Among the information returned by this call are the
object's size (st_size), permissions (st_mode), owner (st_uid), and group (st_gid).
fchown(2) To change the ownership of a shared memory object.
fchmod(2) To change the permissions of a shared memory object.
Versions
POSIX shared memory is supported since Linux 2.4 and glibc 2.2.
Persistence
POSIX shared memory objects have kernel persistence: a shared memory object will exist until the system is shut down, or until all pro-
cesses have unmapped the object and it has been deleted with shm_unlink(3)
Linking
Programs using the POSIX shared memory API must be compiled with cc -lrt to link against the real-time library, librt.
Accessing shared memory objects via the filesystem
On Linux, shared memory objects are created in a (tmpfs(5)) virtual filesystem, normally mounted under /dev/shm. Since kernel 2.6.19,
Linux supports the use of access control lists (ACLs) to control the permissions of objects in the virtual filesystem.
NOTES
Typically, processes must synchronize their access to a shared memory object, using, for example, POSIX semaphores.
System V shared memory (shmget(2), shmop(2), etc.) is an older shared memory API. POSIX shared memory provides a simpler, and better
designed interface; on the other hand POSIX shared memory is somewhat less widely available (especially on older systems) than System V
shared memory.
SEE ALSO
fchmod(2), fchown(2), fstat(2), ftruncate(2), mmap(2), mprotect(2), munmap(2), shmget(2), shmop(2), shm_open(3), shm_unlink(3), sem_over-
view(7)
COLOPHON
This page is part of release 4.15 of the Linux man-pages project. A description of the project, information about reporting bugs, and the
latest version of this page, can be found at https://www.kernel.org/doc/man-pages/.
Linux 2016-12-12 SHM_OVERVIEW(7)