Thanks for the reply I don't know much abou the application, but there is NO db running on the system.
As a first step I will try to change the number of virtual CPU's and AIXTHREAD_SCOPE, but this will take time, as every change requires a long process...
can someone tell me a good site to go to in order to learn this. please do not recommen nay books because i dont have interest in that. if you know of any good sites with good straight forward explanation on how to split loads on machines that has excessive loading, please let me know
Also,... (1 Reply)
Hi all,
long time ago I posted something, but now, it is needed again :(
Currently, I am handling with a big NFS Server for more than 200 clients, this sever has to work with 256 NFSDs. Because of this huge amount of NFSDs, there are thousands of small write accesses down to the disk and... (3 Replies)
Hi to all,
I'm interested in finding an introduction about Performance Tuning under Unix (or Linux); can somebody please point me in the right direction?
Best regards (1 Reply)
Sorry,
This is out of scope of this group.But I require the clarification pretty urgently.
My Oracle database is parallely enabled.
Still,in a particular table queries do not work "parallely" always.
How is this? (9 Replies)
Hi All,
In last one week, i have posted many questions in this portal. At last i am succeeded to make my 1st unix script.
following are 2 points where my script is taking tooooo long.
1. Print the total number of records excluding header & footer. I have found that awk 'END{print NR -... (2 Replies)
Hi,
I am facing a strange issue. Application is deployed in a cluster with 2 Unix nodes (with same configuration). On one node the application is working fine but on another node we see this behavior I found using vmstat- when the server is not yet started everything is OK; when you start the... (3 Replies)
Dear all,
I have a Local zone , where users feel that performance is not good.
Is it wise to collect the inputs from the local zone rather than taking from the global zone.
And also Can I tune from Global zone , so that it will reflect in local zone.
Rgds
rj (2 Replies)
Overview:
Introduction
What Does Success Mean?
What Does Performance Mean?
Every Picture is Worth a Thousand Words
Work Like a Physicist
Work Like You Walk - One Step at a Time
Learn to Know Your System
Choose Your Weapons!
Tools of the Trade 1 - vmstat
A Little Theory Along the Way -... (1 Reply)
I have a IBM Power9 server coupled with a NVMe StorWize V7000 GEN3 storage, doing some benchmarks and noticing that single thread I/O (80% Read / 20% Write, common OLTP I/O profile) seems slow.
./xdisk -R0 -r80 -b 8k -M 1 -f /usr1/testing -t60 -OD -V
BS Proc AIO read% IO Flag IO/s ... (8 Replies)
Discussion started by: c3rb3rus
8 Replies
LEARN ABOUT BSD
posix_madvise
POSIX_MADVISE(3) Linux Programmer's Manual POSIX_MADVISE(3)NAME
posix_madvise - give advice about patterns of memory usage
SYNOPSIS
#include <sys/mman.h>
int posix_madvise(void *addr, size_t len, int advice);
Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
posix_madvise():
_POSIX_C_SOURCE >= 200112L
DESCRIPTION
The posix_madvise() function allows an application to advise the system about its expected patterns of usage of memory in the address range
starting at addr and continuing for len bytes. The system is free to use this advice in order to improve the performance of memory
accesses (or to ignore the advice altogether), but calling posix_madvise() shall not affect the semantics of access to memory in the speci-
fied range.
The advice argument is one of the following:
POSIX_MADV_NORMAL
The application has no special advice regarding its memory usage patterns for the specified address range. This is the default
behavior.
POSIX_MADV_SEQUENTIAL
The application expects to access the specified address range sequentially, running from lower addresses to higher addresses.
Hence, pages in this region can be aggressively read ahead, and may be freed soon after they are accessed.
POSIX_MADV_RANDOM
The application expects to access the specified address range randomly. Thus, read ahead may be less useful than normally.
POSIX_MADV_WILLNEED
The application expects to access the specified address range in the near future. Thus, read ahead may be beneficial.
POSIX_MADV_DONTNEED
The application expects that it will not access the specified address range in the near future.
RETURN VALUE
On success, posix_madvise() returns 0. On failure, it returns a positive error number.
ERRORS
EINVAL addr is not a multiple of the system page size or len is negative.
EINVAL advice is invalid.
ENOMEM Addresses in the specified range are partially or completely outside the caller's address space.
VERSIONS
Support for posix_madvise() first appeared in glibc version 2.2.
CONFORMING TO
POSIX.1-2001.
NOTES
POSIX.1 permits an implementation to generate an error if len is 0. On Linux, specifying len as 0 is permitted (as a successful no-op).
In glibc, this function is implemented using madvise(2). However, since glibc 2.6, POSIX_MADV_DONTNEED is treated as a no-op, because the
corresponding madvise(2) value, MADV_DONTNEED, has destructive semantics.
SEE ALSO madvise(2), posix_fadvise(2)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 2017-09-15 POSIX_MADVISE(3)