[mythtv-users] system profiling / cpu usage revisited

[mOjO]

Brian Lalor wrote:

> Gregorio Gervasio Jr. wrote:
> 
>>         Maybe it is important -- are you sure you haven't enabled the
>> HQ and 4MV options?  Last time I checked, the first one bumped up CPU
>> usage on my Athlon 2500XP+ from 15-20% to 40-50%.  The second one
>> pretty much maxes out the system.  This is with LiveTV MPEG-4
>> @480x480.  Also, other people have reported strange results when using
>> non-standard values for min/max quality.
> 
> 
> I'm using the standard settings.  Pertinent settings from the 
> codecparams table for the Default profile:
> (1,'width','480');
> (1,'height','480');
> (1,'mpeg4bitrate','2200');
> (1,'mpeg4maxquality','2');
> (1,'mpeg4minquality','15');
> (1,'mpeg4qualdiff','3');
> (1,'mpeg4scalebitrate','1');
> (1,'mpeg4optionvhq','0');
> (1,'mpeg4option4mv','0');
> (1,'samplerate','32000');
> (1,'mp3quality','7');
> 
>>         Are you sure you didn't accidentally compile for debug?  Did
>> you do anything different when you ran "./configure"?  That's actually
>> the critical one since it sets up the libavcodec build.  From what
>> I've seen, there's not much to be gained by using "-march=athlon"
>> anyway so you could just stick with the default compiler options.
> 
> 
> The only things I changed were settings.pro to force -march=athlon-xp 
> and the --cpu=athlon-xp option to configure.
> 

i thought if you were to set -march=athlon-xp that you didnt need to set 
-mcpu am i getting my flags confused? unless the cpu flag refers to the 
  HOST flag which should be i686... right? im just going by what it says 
in the gentoo make.conf files comments and thats how i configured the 
settings.pro file before i compiled mythtv...

lemme paste some stuff in here from that make.conf file and you guys 
tell me if my thinking is all messed up..

mOjO

# Host and optimization settings
# ==============================
#
# For optimal performance, enable a CFLAGS setting appropriate for your CPU.
#
# Please note that if you experience strange issues with a package, it 
may be
# due to gcc's optimizations interacting in a strange way. Please test the
# package (and in some cases the libraries it uses) at default
# optimizations
# before reporting errors to developers.
#
# -mcpu=<cpu-type> means optimize code for the particular type of CPU
# without
# breaking compatibility with other CPUs.
#
# -march=<cpu-type> means to take full advantage of the ABI and
# instructions
# for the particular CPU; this will break compatibility with older CPUs
# (for
# example, -march=athlon-xp code will not run on a regular Athlon, and
# -march=i686 code will not run on a Pentium Classic.
#
# CPU types supported in gcc-3.2 and higher: athlon-xp, athlon-mp,
# athlon-tbird, athlon, k6, k6-2, k6-3, i386, i486, i586 (Pentium), i686
# (PentiumPro), pentium, pentium-mmx, pentiumpro, pentium2 (Celeron),
#  pentium3.
# Note that Gentoo Linux 1.4 and higher include at least gcc-3.2.
#
# CPU types supported in gcc-2.95*: k6, i386, i486, i586 (Pentium), i686
# (Pentium Pro), pentium, pentiumpro Gentoo Linux 1.2 and below use
# gcc-2.95*
#
# CRITICAL WARNINGS: 
****************************************************** #
# ATHLON-4 will generate invalid SSE  instructions; use 'athlon' 
instead. #
# PENTIUM4 will generate invalid SSE2 instructions; use 'pentium3' 
instead. #
# 
************************************************************************* #
#
# Decent examples:
#
CFLAGS="-march=athlon-xp -pipe -O3"
#CFLAGS="-march=pentium3 -O3 -pipe"

# If you set a CFLAGS above, then this line will set your default C++ 
flags to
# the same settings.
CXXFLAGS="${CFLAGS}"

# Host Setting
# ============
#
# If you are using a Pentium Pro or greater processor, leave this line 
as-is;
# otherwise, change to i586, i486 or i386 as appropriate. All modern systems
# (even Athlons) should use "i686-pc-linux-gnu". All K6's are i586.
#
CHOST="i686-pc-linux-gnu"