[Powertop] Too much memory consumption by powertop

[Thomas Renninger <trenn at suse.de>]

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As powertop list is for subscribers only, here Takashi's
findings concerning a big memory waste fowarded:

----------  Forwarded Message  ----------

Subject: Too much memory consumption by powertop
Date: Tuesday, April 28, 2015, 05:32:41 PM
From: Takashi Iwai <tiwai(a)suse.de>
To: powertop(a)lists.01.org
CC: trenn(a)suse.de

Hi,

I noticed that powertop consumes way too much memory than needed.  It
constantly takes over 170MB RES, sometimes over 200MB.

Then I looked at profile, and it showed that most of memory is
allocated for newpad_sp().  Indeed, the current code allocates a pad
of the fixed size of 1000x1000 (!) for each tab, and we have five
tabs, so five times of that.  No wonder that such a small neat CUI
program is so hungry.

For example, a hack like below already reduces the memory footprint
to around 20MB, 90% cut.  Not bad.

--- a/src/display.cpp
+++ b/src/display.cpp
@@ -48,7 +48,7 @@ void create_tab(const string &name, cons
        if (!w)
                w = new(class tab_window);
 
-       w->win = newpad(1000,1000);
+       w->win = newpad(80,160); // XXX FIXME XXX
        tab_names.push_back(name);
        tab_windows[name] = w;
        tab_translations[name] = translation;

Can anyone look into this and give a better / smarter solution?


thanks,

Takashi
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