Re: [gentoo-user] I want to play movies without hangs

[Alex Schuster]

Walter Dnes writes:

> On Thu, Feb 16, 2012 at 04:29:48PM +0100, Alex Schuster wrote
>
> > Then my hardware broke, and I got new one...
>
>   I had ***EXACTLY THE SAME PROBLEM ON A FRESH INSTALL***.  In My case
> it was a 4+ year old Dell with onboard Intel GPU that was having
> problems playing NHL Gamecenter Live streams at the slowest speed.  I
> solved the problem and sped up everything by doing...
> 1) emerge system
> 2) emerge world
> 3) rebuild the kernel and reboot

Good idea, Walter! But not in my case. The system had been set up long
ago, and I did an emerge -e @world in the past already.

>   A fresh install will have the stage 3 binaries built with
> lowest-common-denominator x86 or amd64 code (depending if you chose 32
> or 64 bit install).  This is necessary in order to allow the install
> code to run on all CPUs with the target platform.  The downside is that
> you lose all the optimisations that make Gentoo scream.  Rebuilding the
> install as described above builds optimized (i.e. faster) binaries.  My
> CFLAGS line in /etc/make.conf is...
>
> CFLAGS="-O2 -march=native -mfpmath=sse -fomit-frame-pointer -pipe"
> CXXFLAGS="${CFLAGS}"

I had those, when I upgraded the hardware:
CFLAGS="-march=k8-sse3 -mfpmath=sse -O2 -pipe"
Or something very silimar.

But I also just did an emerge -e @world on the new system, using more
sophisticated CFLAGS. I got them by doing like suggested on [*], using
what -march=natve would do. And adding support for this graphite
stuff. They are:
CFLAGS="-pipe -march=amdfam10 -O2 \
        -floop-interchange -floop-strip-mine -floop-block \
        -msse -msse2 -msse3 -msse4 -msse4.1 -msse4.2 -m3dnow \
        -mcx16 -msahf -maes -mpclmul -mpopcnt -mabm -mlwp -mavx \
        --param l1-cache-size=16 --param l1-cache-line-size=64 \
        --param l2-cache-size=2048"

>   Before rebuilding your system, go over your USE flags to make sure
> you've got the maximum optimization.  To find out what your CPU
> supports, execute the command
>
> grep flags /proc/cpuinfo | head -1
>
>   This will define the limits what your system can support.  For
> instance, mplayer can use the following flags...
>
> waltdnes@d530 ~ $ emerge -pv mplayer
>
> These are the packages that would be merged, in order:
>
> Calculating dependencies... done!
> [ebuild   R    ] media-video/mplayer-1.0_rc4_p20110322-r1  USE="X a52
> alsa ass dga encode gif jpeg mmx mmxext mng mp3 opengl png quicktime
> real rtmp sse sse2 ssse3 theora truetype win32codecs x264 xv xvid xvmc
> -3dnow -3dnowext -aalib (-altivec) -amr (-aqua) -bidi -bindist -bl
> -bluray -bs2b -cddb -cdio -cdparanoia -cpudetection -custom-cpuopts
> -debug -dirac -directfb -doc -dts -dv -dvb -dvd -dvdnav (-dxr3) -enca
> (-esd) -faac -faad -fbcon -ftp -ggi -gsm -iconv -ipv6 -jack -joystick
> -jpeg2k -ladspa -libcaca -libmpeg2 -lirc -live -lzo -mad -md5sum
> -mpg123 -nas -network -nut -openal -osdmenu -oss -pnm -pulseaudio -pvr
> -radio -rar -rtc -samba -schroedinger -sdl -shm -speex -tga -toolame
> -tremor -twolame -unicode -v4l -vdpau -vidix -vorbis -vpx -xanim
> -xinerama -xscreensaver -zoran" VIDEO_CARDS="-mga -s3virge -tdfx -vesa"
> 0 kB
>
>   Your CPU will obviously support a different set of USE flags than
> mine.  Check the files /usr/portage/profiles/use.desc for a list of
> global flags and /usr/portage/profiles/use.local.desc for
> package-specific flags.

These are my USE flags for mplayer, they should be fine:
[ebuild   R    ] media-video/mplayer-1.0_rc4_p20120213  USE="3dnow
3dnowext X a52 aalib alsa ass cdio dga directfb dts dv dvb dvd dvdnav
enca encode faad fbcon ftp ggi gif iconv ipv6 jack jpeg jpeg2k live mad
mmx mmxext mng mp3 nas network openal opengl osdmenu oss png pnm
quicktime rar real rtc samba sdl shm speex sse sse2 ssse3 theora toolame
tremor truetype twolame unicode vorbis x264 xinerama xscreensaver xv xvid
(-altivec) (-aqua) -bidi -bindist -bl -bluray -bs2b -cddb -cdparanoia
-cpudetection -debug -doc (-dxr3) (-esd) -faac -gsm -joystick -ladspa
-libcaca -libmpeg2 -lirc -lzo -md5sum -nut -pulseaudio -pvr -radio -rtmp
-tga -v4l -vdpau (-vidix) (-win32codecs) -xanim -xvmc -zoran"
VIDEO_CARDS="-mga -s3virge -tdfx" 0 kB

Now I'm bulding a new kernel, using genkernel, and without providing a
custom made .config. Just in case I have some weird setting somewhere
(debug output for SCSI stuff or something like that).

[later...]

So I did. Argh. I thought genkernel was smart enough to generate a
working kernel from scratch, if no existing .config would be given. But
the initramfs could not open my encrypted root partition, until I compiled
XTS and AES directly into the kernel, not only as modules. Genkernel did
not include modules for my NIC, somewhat annoying because I had to wait
several minutes for mysql to start, until I could open a root shell. KDM
was already running at that time, but I only saw a blank screen, because
the radeon stuff was not compiled with KMS. There's also something
wrong with my hardware clock. And iotop does not work, the kernel is
missing CONFIG_TASKSTATS, CONFIG_TASK_DELAY_ACCT
and CONFIG_TASK_IO_ACCOUNTING.

But now I have KDE running again. As soon as I do my dd command, mplayer
stutters, sometimes hanging for seconds. So it's probably not a flaw in
my kernel .config. Too bad, I hoped that was the problem.

I'm out of ideas now. This is really annoying, my system is fast, mplayer
is using around 20% only, the system is mostly idle, but when there is
I/O, videos do not run smoothly. And I do not want to copy every movie I
want to watch to another drive first.

BTW, when I do the dd if=/dev/zero of=/home/argh bs=10M count=1000
command, and interrupt with Ctrl-C, it takes some seconds until it stops.
Shouldn't this happen immediately, unless I specify a very large block
size? Writing speed is okay, 100 MB/s.

Time to go to sleep now.

[*] http://en.gentoo-wiki.com/wiki/Safe_Cflags#-march.3Dnative

	Wonko