2008-06-24 11:19:36 global memory usage

Linux Newbie (INDIA)

Message: 57812

Hi ,

Is it possible to find the global memory usage of an individual file in an Application(user space) using bfin-uclinux-objdump? or is there any other way to find it?

Thanks in Advance

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2008-06-24 11:40:47 Re: global memory usage

Mike Frysinger (UNITED STATES)

Message: 57814

objdump runs on your development host and shows you information about binaries ... it doesnt work with runtime images at all

look at the files in /proc/<pid>/ and read the proc(5) man page

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2008-06-25 05:36:05 Re: global memory usage

Linux Newbie (INDIA)

Message: 57854

Hi,

On executing following commands via telnet to board, I am getting following msg's

1. root:~> cat /proc/89/mem

cat: read error: No such process

2. root:~> cat /proc/92/status

Groups:

Mem: 29351872 bytes

Slack: 4878496 bytes

Shared: 0 bytes

Threads: 1

Also the same memory info is displayed on executing second command for all thread ID's.

Can you please suggest how to look for global memory usage of each and every threads in the application.

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2008-06-25 07:08:04 Re: global memory usage

Mike Frysinger (UNITED STATES)

Message: 57855

i already gave you the document to read: man 5 proc

it explains every file in there and how to use it

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2008-06-27 03:41:01 Re: global memory usage

Linux Newbie (INDIA)

Message: 57950

Hi,

I created a simple application which has 4Mbytes global buffer. On running the application in background and watching the memory it shows 8Mytes as used.

compiled using bfin-linux-uclibc-gcc main.c -o main

Intial memory

root:~> free

total used free shared buffers

Mem: 42904 3588 39316 0 104

while application is running

root:~> free

total used free shared buffers

Mem: 42904 12340 30564 0 104

Can you please explain why this behaviour???

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2008-06-27 05:03:09 Re: global memory usage

Yi Li (CHINA)

Message: 57952

It may be expected behavior. "cat /proc/buddyinfo" before and after running the test to see what is the available memory block.

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2008-06-27 05:05:56 Re: global memory usage

Mike Frysinger (UNITED STATES)

Message: 57953

read the documents i already pointed you to and correlate the files in the proc. you're probably allocating more than 4 megs total, which means you hit: http://docs.blackfin.uclinux.org/doku.php?id=kernel_space_memory_allocation

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2008-06-29 11:02:50 Re: global memory usage

Linux Newbie (INDIA)

Message: 58050

Hi ,

Thanks for the document, it helped me to gain more understanding.

Still need few issues to get clarified

After compiling my application, I am getting its size as follows

text data bss dec hex filename

1982426 984175 7998848 10965449 a751c9 app

When I run this application and issue free command it shows as follows

root:~> free

total used free shared buffers

Mem: 42584 40724 1860 0 184

Now I removed some global buffers in the project and its total sizes comes to around 1.7Mbytes and I did the same process again

text data bss dec hex filename

1982402 984175 6178956 9145533 8b8cbd app

When I run the application and issue the free it shows as follows

root:~> free

total used free shared buffers

Mem: 42584 32876 9708 0 236

Now the free size is increased very much. It means , is there any constraint in allocating global buffers? system wise do we need to take care of any pre-cautions to optimize memory? I suspect its due to page boundary that after removing 1.7 Mbytes of memory almost 8Mbytes has been freed? is my understanding correct?

Thanks in Advcance

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2008-06-29 12:01:03 Re: global memory usage

Mike Frysinger (UNITED STATES)

Message: 58051

did you read that wiki page i gave you ? it talks about how the kernel memory manager works in power of twos.

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2008-06-29 12:35:32 Re: global memory usage

Linux Newbie (INDIA)

Message: 58052

Yes Mike.

Also when we do insmod, system crashes due to page allocation failure. I believe it is due to memory fragmentation.