#include<stdio.h>
#include<stdlib.h>
#include<sys/time.h>
#include<time.h>
#include "rdtsc.h"
#define SIZE 4*64*1024
int main()
{
unsigned long long a,b;
int arr[SIZE]={0};
int i;
register int r;
a=rdtsc();
r=arr[0];
b=rdtsc();
printf("1st element Access Cycles = %llu\n",b-a);
a=rdtsc();
r=arr[1];
b=rdtsc();
printf("2nd Element Access Cycles = %llu\n",b-a);
}
In the above code I am trying to determine the number of cycles it takes to fetch the first element of an array from memory, and then the next cached element. When I execute this snippet, I am getting almost identical number of cycles for both accesses ~81 cycles. Can anybody explain me why this is happening. By all means, the first access should be very costly, but the access to next sequential element which has been brought into the cache should be much lesser.
I'm looking to get the file cache portion of physical (real) memory on a Solaris workstation (Similar to the Cache: line in /proc/meminfo on some Linux systems):
# swap -s; swap -l; vmstat 2 2; echo "::memstat" | mdb -k
total: 309376k bytes allocated + 41428k reserved = 350804k used,... (5 Replies)
Hi,
I'm running a debian lenny 1GB ram, but with a high I/O. This server has 400IOPS and 3MB/s sustain. So, I noted cached memory use 800MB, buffered memory use 50MB, and no free memory is available. Questions:
What does mean such a high cached memory?
Who's using this cached memory?
Is... (3 Replies)
18:45:47 # free -m
total used free shared buffers cached
Mem: 96679 95909 770 0 1530 19550
-/+ buffers/cache: 74828 21851
Swap: 12287 652 11635
Hi all. The below output is from a RHEL 4.5... (0 Replies)
Right now i am using Red Hat Enterprise Linux AS release 4 and cache memory occupying around 1.5GB mentioned below,
total used free shared buffers cached
Mem: 2026 2021 5 0 161 1477
-/+ buffers/cache: 382 1644 ... (4 Replies)
When I run 'top' command,I see the following
Memory: 32G real, 12G free, 96G swap free
Though it shows as 12G free,I am not able to account for processes that consume the rest 20G.
In my understanding some process should be consuming atleast 15-16 G but I am not able to find them.
Is... (1 Reply)
The environment is Java/Windows. The program keeps near real-time state in memory cache, which is updated by multiple sources, size of the cache is roughly 500 MB, frequency of updates is ~ 20 per second. I am looking into different ways to keep current snapshot of the memory on the disk for a)... (9 Replies)
hi all,
i have noticed that my server has 64 GB RAM and i have application in this server but the server has free memory only 15% and utilized 85% however it didn't eat from swap .
does any parameter can be configured in kernel to make the system clear memory from cache like linux
i found... (4 Replies)
i wish to clear memory cache on a production box and i was wondering what is the worst that can happen if i do?
i already tested this on a backup server and everything seemed fine.
but i need to know from you experts what are the worst things that can happen when i run it on a real server:
... (5 Replies)
Hi,
I am new to AIX, Can someone please help me how to know the swap space, total physical memory and system cache?
We are using AIX 5.3.
Thanks! (3 Replies)
Discussion started by: Phaneendra G
3 Replies
LEARN ABOUT PHP
current
CURRENT(3) 1 CURRENT(3)current - Return the current element in an arraySYNOPSIS
mixed current (array &$array)
DESCRIPTION
Every array has an internal pointer to its "current" element, which is initialized to the first element inserted into the array.
PARAMETERS
o $array
- The array.
RETURN VALUES
The current(3) function simply returns the value of the array element that's currently being pointed to by the internal pointer. It does
not move the pointer in any way. If the internal pointer points beyond the end of the elements list or the array is empty, current(3)
returns FALSE.
Warning
This function may return Boolean FALSE, but may also return a non-Boolean value which evaluates to FALSE. Please read the section on
Booleans for more information. Use the === operator for testing the return value of this function.
EXAMPLES
Example #1
Example use of current(3) and friends
<?php
$transport = array('foot', 'bike', 'car', 'plane');
$mode = current($transport); // $mode = 'foot';
$mode = next($transport); // $mode = 'bike';
$mode = current($transport); // $mode = 'bike';
$mode = prev($transport); // $mode = 'foot';
$mode = end($transport); // $mode = 'plane';
$mode = current($transport); // $mode = 'plane';
$arr = array();
var_dump(current($arr)); // bool(false)
$arr = array(array());
var_dump(current($arr)); // array(0) { }
?>
NOTES
Note
You won't be able to distinguish the end of an array from a boolean FALSE element. To properly traverse an array which may contain
FALSE elements, see the each(3) function.
SEE ALSO end(3), key(3), each(3), prev(3), reset(3), next(3).
PHP Documentation Group CURRENT(3)