Re: How do you accurately determine a process' RAM usage?

[P@draigBrady.com]

Mauricio Lin wrote:
> Hi Brady,
> 
> On 7/20/05, P@draigbrady.com <P@draigbrady.com> wrote:
> 
>>The following shell gets the shared values for the
>>first httpd process:
>>
>>FIRST_HTTPD=`ps -C httpd -o pid= | head -1 | tr -d ' '`
>>HTTPD_STATM_SHARED=$(expr 4 '*' `cut -f3 -d' ' /proc/$FIRST_HTTPD/statm`)
>>HTTPD_SMAPS_SHARED=$(grep Shared /proc/$FIRST_HTTPD/smaps | tr -s ' '
>>| cut -f2 -d' ' | ( tr '\n' +; echo 0 ) | bc)
>>
>>
>>This shows that "smaps" reports 3060 KB more shared mem than "statm".
>>However adding up all the anon sections in smaps only gives 2456 KB?
> 
> 
> You are adding up all Shared_Clean and Shared_Dirty as Shared, right?

yes. Look at the command I posted.

>>When doing this I also noticed that there are duplicate
>>entries in smaps. Any ideas why?
> 
> 
> Each pair of address per line indicates the start and end address of a
> memory area (VMA) such as:
> 
> b7f7d000-b7f7e000 
> 
> This means that an specific memory area start on virtual address 
> b7f7d000 and end on b7f7e000 .
> 
> An mapped file like /lib/ld-2.3.3.so is organized in different memory
> areas. The memory area can be a text section, data section or bss. So
> it is normal you find the same filename mapped in more than one memory
> area.

yes. Look at the command I posted.
There are multiple entries with the _same addresses_

>>grep -F - /proc/$FIRST_HTTPD/smaps | sort | uniq -d -c

-- 
Pádraig Brady - http://www.pixelbeat.org
--