[PD] linux - faster load first time

Mathieu Bouchard matju at artengine.ca
Thu Oct 4 17:56:43 CEST 2007

On Thu, 4 Oct 2007, Kevin McCoy wrote:

> I notice this not only on Pd but on most programs... gnome-terminal
> eventually starting taking so long to start up the first couple of times
> that I gave up and started with xterm, for example.  Firefox takes a long
> time as well and I am using that every day...

Last time that I was having huge slowdowns, I looked at "top" by CPU 
usage, and it was showing a program called "hal" sucking 100% cpu all of 
the time and keeping the cpu hot.

(without any special priorities, in that case, one other program trying 
to get 100% will only get 50%, because cpu is shared equally)

gnome-terminal is an utter waste of RAM, but most people have plenty of 
RAM to waste. "top" now says it has 100 megs virtual RAM of which 9 megs 
are shared RAM, so I might be led to think that it's really taking 91 
megs, but that is false. Say that the process id is 5262; then open the 
pseudo-file /proc/5262/maps as plain text. I have:

   08089000-090c3000 rw-p 08089000 00:00 0          [heap]

Which is the main chunk of process-specific memory. The size is not 
written but you may compute it like this using bash:

   echo $(( 0x090c3000-0x08089000 ))

and then it says 17014784, which is about 16.2 megs of RAM, only. It's a 
lot more RAM than what the scrollback buffers would warrant (here it says 
636k per tab and I have 7 tabs open) but it's not 91 megs.

In a more automated way:

   cat /proc/5262/maps |
   ruby -ne 'a=split;b=a[0].split"-";c=b[1].hex-b[0].hex;puts"#{c} #{a[1]}
   #{a[5]}"' | sort -n

all on one line, sorts all RAM segments of a process per size, and it 
seems that it's counting 25 megs of RAM per Gnome process just for the 
icons, which is mapped read-only. Now, by default, read-only mapped files 
do not take any more RAM than what they take in the disk cache. This is a 
lot less cumbersome than a read-write segment, which is the kind of 
segment that has to be swapped out when you lack RAM.

In short, "top" is not making a good breakdown of RAM usage.

I'd like to hear more reasons why startup and general operation might be 

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| Mathieu Bouchard - tél:+1.514.383.3801, Montréal QC Canada

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