10-06-2008
I suggest you re-post this in the OS-specific forum.
10 More Discussions You Might Find Interesting
1. AIX
Hello AIX gurues...
In order to present the statistics of real memory usage I need to know how much real memory is used by the AIX 5L kernel. No the exact figures of course but some close to the reality.
The AIX is running in a 7GB real machine, it has a HACMP configuration and my concern is... (1 Reply)
Discussion started by: daniels
1 Replies
2. UNIX for Dummies Questions & Answers
Hellp all,
if there is 3G memory in my Unix server I want to know if all the 3G space can be used by ong sigle process. As i know, in Windows, one process can only access at most 1G memory despite there is probably more than 1G memory is equipped. (1 Reply)
Discussion started by: cy163
1 Replies
3. UNIX for Dummies Questions & Answers
Hi,
I need to know how to revoke the access/permission of Kernel for a group. In details, one of the group 'X' is having kernel access/permission and this group can control the Kernel at anytime. How can we revoke this permission/access ?
Thanks,
Rohit.. (13 Replies)
Discussion started by: ronix007
13 Replies
4. UNIX for Advanced & Expert Users
There is a tomcat webserver running that is used to host a java application. Sometime the service goes down with error logs. I see the following error messages in /var/log/messages:
kernel: Out of Memory: Killed process 2990 (co).
Out of Memory: Killed process 25671 (httpd)
Out of Memory:... (7 Replies)
Discussion started by: bsandeep_80
7 Replies
5. UNIX for Advanced & Expert Users
Can kernel process access user address space ? (2 Replies)
Discussion started by: subhotech
2 Replies
6. UNIX for Advanced & Expert Users
Hello, I'm searching for a proper way to let the kernel space ISR(implemented in a kernel module) wake up a user space thread on a hardware interrupt.
Except for sending a real-time signal, is it possible to use a semaphore?
I've searched it on google, but it seems impossible to share a... (0 Replies)
Discussion started by: aaronwong
0 Replies
7. UNIX for Dummies Questions & Answers
hi all,
i want to know y kernel is giving access for multiple users to access a file when one user may be the owner is executing that file. Because other user can manipulate that file when the other user is executing that file, it will give the unexpected result to owner . plz help me... (1 Reply)
Discussion started by: jimmyuk
1 Replies
8. 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)
Discussion started by: ggayathri
4 Replies
9. 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
4 Replies
10. Solaris
Hi ,
In a server /tmp has almost reached 75% and i can see the File system utilization is 48Mb only , so i believe some process is using the /tmp space. I would like to know which process is using /tmp space.
# df -h /tmp
Filesystem size used avail capacity Mounted on
swap ... (9 Replies)
Discussion started by: chidori
9 Replies
PAE(4) BSD/i386 Kernel Interfaces Manual PAE(4)
NAME
PAE -- Physical Address Extensions
SYNOPSIS
options PAE
DESCRIPTION
The PAE option provides support for the physical address extensions capability of the Intel Pentium Pro and above CPUs, and allows for up to
64 gigabytes of memory to be used in systems capable of supporting it. With the PAE option, memory above 4 gigabytes is simply added to the
general page pool. The system makes no distinction between memory above or below 4 gigabytes, and no specific facility is provided for a
process or the kernel to access more memory than they would otherwise be able to access, through a sliding window or otherwise.
SEE ALSO
smp(4), tuning(7), config(8), bus_dma(9)
HISTORY
The PAE option first appeared in FreeBSD 4.9 and FreeBSD 5.1.
AUTHORS
Jake Burkholder <jake@FreeBSD.org>
BUGS
Since KLD modules are not compiled with the same options headers that the kernel is compiled with, they must not be loaded into a kernel com-
piled with the PAE option.
Many devices or their device drivers are not capable of direct memory access to physical addresses above 4 gigabytes. In order to make use
of direct memory access IO in a system with more than 4 gigabytes of memory when the PAE option is used, these drivers must use a facility
for remapping or substituting physical memory which is not accessible to the device. One such facility is provided by the busdma interface.
Device drivers which do not account for such devices will not work reliably in a system with more than 4 gigabytes of memory when the PAE
option is used, and may cause data corruption. The PAE kernel configuration file includes the PAE option, and explicitly excludes all device
drivers which are known to not work or have not been tested in a system with the PAE option and more than 4 gigabytes of memory.
Many parameters which determine how memory is used in the kernel are based on the amount of physical memory. The formulas used to determine
the values of these parameters for specific memory configurations may not take into account the fact there may be more than 4 gigabytes of
memory, and may not scale well to these memory configurations. In particular, it may be necessary to increase the amount of virtual address
space available to the kernel, or to reduce the amount of a specific resource that is heavily used, in order to avoid running out of virtual
address space. The KVA_PAGES option may be used to increase the kernel virtual address space, and the kern.maxvnodes sysctl(8) may be used
to decrease the number of vnodes allowed, an example of a resource that the kernel is likely to overallocate in large memory configurations.
For optimal performance and stability it may be necessary to consult the tuning(7) manual page, and make adjustments to the parameters docu-
mented there.
BSD
April 8, 2003 BSD