Re: GIT PULL] ext4 updates for 3.4

From: Fengguang Wu
Date: Wed Mar 28 2012 - 20:46:59 EST

On Wed, Mar 28, 2012 at 04:45:55PM -0700, Linus Torvalds wrote:
> On Wed, Mar 28, 2012 at 4:36 PM, Linus Torvalds
> <torvalds@xxxxxxxxxxxxxxxxxxxx> wrote:
> >
> > I have no real data for this, though - just a "mouse pointer
> > occasionally freezing up". So I'm looking for a potential "hmm, that
> > makes me wonder if..." kind of reaction.
> Heh. It may have been that my wireless mouse was having some issue
> syncing properly with the receiver. I unplugged and replugged the
> receiver, and I seem unable to reproduce the problem. So this may have
> been just an actual hardware latency issue, rather than the kernel
> having bad latency.

Yeah my wireless mouse also becomes insensitive nowadays (perhaps
running low on battery power?)

> But if it made you go "hmm, I should check xyz", please do go ahead
> and check it anyway, just in case ;)

I just booted into the new kernel, did some compile testing and it looks good.

Anyway the classical "mouse pointer freezing up" problems are often
caused by waits in direct page reclaim and can be confirmed with large

allocstall # the number of direct reclaims
nr_vmscan_write # the number of pageout()s

numbers in /proc/vmstat

FYI I'm testing desktop responsiveness remotely (as you know it could
be a painful test). The test scheme is to run

make -j16 (or any other workloads)

as well as a small script to start some X apps and cycle through the
windows. By checking if there are second(s) long gaps in the below
progress messages, I confirm that the desktop is running smoothly.

time window title
157.68 A swapping-desktop-test
157.73 A *Unsaved Document 1 - gedit
157.76 A Restore Session - Iceweasel
157.80 A Sudoku
157.83 A LibreOffice 3.4
157.91 A System Settings
158.01 A urxvt
158.01 A xeyes
158.06 A bay:/home/wfg/swapping-desktop-test - ZSH
158.08 A Xpdf: /usr/share/doc/shared-mime-info/shared-mime-info-spec.pdf
158.10 A bay:/home/wfg/swapping-desktop-test - ZSH
158.17 A
158.20 A
158.21 A
158.22 A
158.24 A
158.25 A Dictionary
158.27 A bay:/home/wfg/swapping-desktop-test - ZSH
158.30 A Tetravex
158.34 A Chess
158.37 A System Monitor
158.41 A Mines
158.50 A Robots
158.62 A Iagno
158.68 A Four-in-a-row
158.75 A Five or More
158.79 A Klondike
158.82 A Klotski
158.90 A Mahjongg - Easy
158.93 A Tali
159.00 A Desktop Help
159.08 A Home

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