Re: [PATCH 2/3] vmscan: make mapped executable pages the first class citizen

[Wu Fengguang <fengguang.wu@intel.com>]

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On Mon, Jun 08, 2009 at 11:34:06PM +0800, Christoph Lameter wrote:
> On Mon, 8 Jun 2009, Wu Fengguang wrote:
>
> > 1.2) test scenario
> >
> > - nfsroot gnome desktop with 512M physical memory
> > - run some programs, and switch between the existing windows
> >   after starting each new program.
>
> Is there a predefined sequence or does this vary between tests? Scripted?

Yes it's scripted testing and has a predefined sequence.
The scripts are attached for your reference.

> What percentage of time is saved in the test after due to the
> modifications?
> Around 20%?

It's 50%, hehe. I've posted the startup times for each program:

  before       after    programs
    0.02        0.02    N xeyes
    0.75        0.76    N firefox
    2.02        1.88    N nautilus
    3.36        3.17    N nautilus --browser
    5.26        4.89    N gthumb
    7.12        6.47    N gedit
    9.22        8.16    N xpdf /usr/share/doc/shared-mime-info/shared-mime-info-spec.pdf
   13.58       12.55    N xterm
   15.87       14.57    N mlterm
   18.63       17.06    N gnome-terminal
   21.16       18.90    N urxvt
   26.24       23.48    N gnome-system-monitor
   28.72       26.52    N gnome-help
   32.15       29.65    N gnome-dictionary
   39.66       36.12    N /usr/games/sol
   43.16       39.27    N /usr/games/gnometris
   48.65       42.56    N /usr/games/gnect
   53.31       47.03    N /usr/games/gtali
   58.60       52.05    N /usr/games/iagno
   65.77       55.42    N /usr/games/gnotravex
   70.76       61.47    N /usr/games/mahjongg
   76.15       67.11    N /usr/games/gnome-sudoku
   86.32       75.15    N /usr/games/glines
   92.21       79.70    N /usr/games/glchess
  103.79       88.48    N /usr/games/gnomine
  113.84       96.51    N /usr/games/gnotski
  124.40      102.19    N /usr/games/gnibbles
  137.41      114.93    N /usr/games/gnobots2
  155.53      125.02    N /usr/games/blackjack
  179.85      135.11    N /usr/games/same-gnome
  224.49      154.50    N /usr/bin/gnome-window-properties
  248.44      162.09    N /usr/bin/gnome-default-applications-properties
  282.62      173.29    N /usr/bin/gnome-at-properties
  323.72      188.21    N /usr/bin/gnome-typing-monitor
  363.99      199.93    N /usr/bin/gnome-at-visual
  394.21      206.95    N /usr/bin/gnome-sound-properties
  435.14      224.49    N /usr/bin/gnome-at-mobility
  463.05      234.11    N /usr/bin/gnome-keybinding-properties
  503.75      248.59    N /usr/bin/gnome-about-me
  554.00      276.27    N /usr/bin/gnome-display-properties
  615.48      304.39    N /usr/bin/gnome-network-preferences
  693.03      342.01    N /usr/bin/gnome-mouse-properties
  759.90      388.58    N /usr/bin/gnome-appearance-properties
  937.90      508.47    N /usr/bin/gnome-control-center
 1109.75      587.57    N /usr/bin/gnome-keyboard-properties
 1399.05      758.16    N : oocalc
 1524.64      830.03    N : oodraw
 1684.31      900.03    N : ooimpress
 1874.04      993.91    N : oomath
 2115.12     1081.89    N : ooweb
 2369.02     1161.99    N : oowriter


> > (1) begin:     shortly after the big read IO starts;
> > (2) end:       just before the big read IO stops;
> > (3) restore:   the big read IO stops and the zsh working set restored
> > (4) restore X: after IO, switch back and forth between the urxvt and firefox
> >                windows to restore their working set.
>
> Any action done on the firefox sessions? Or just switch to a firefox
> session that needs to redraw?

After starting each new program, a new tab is opened in firefox to render a
simple web page. It's the same web page, so firefox may actually cache it.

> > The above console numbers show that
> >
> > - The startup pgmajfault of 2.6.30-rc4-mm is merely 1/3 that of 2.6.29.
> >   I'd attribute that improvement to the mmap readahead improvements :-)
>
> So there are other effects,,, You not measuring the effect only this
> patchset?

Yes there are additional effects in the .29 vs .30 comparisons.
But the following .30 vs .30 comparisons in X can lead to the same conclusions
except for this additional effect.

> > - The pgmajfault increment during the file copy is 633-630=3 vs 260-210=50.
> >   That's a huge improvement - which means with the VM_EXEC protection logic,
> >   active mmap pages is pretty safe even under partially cache hot streaming IO.
>
> Looks good.
>
> > - The absolute nr_mapped drops considerably to 1/9 during the big IO, and the
> >   dropped pages are mostly inactive ones. The patch has almost no impact in
> >   this aspect, that means it won't unnecessarily increase memory pressure.
> >   (In contrast, your 20% mmap protection ratio will keep them all, and
> >   therefore eliminate the extra 41 major faults to restore working set
> >   of zsh etc.)
>
> Good.

Thanks,
Fengguang

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