[mythtv-users] Recompiling glibc with optimizations reduces Mythtv's cpu usage.

[roger]

I've seen one report of this elsewhere.

What I was seeing, Mythtv Live TV consume an overall >99% of my 1Ghz
pentium3 cpu resource on my laptop.  During Live TV playback, I was
seeing quite a few "prebuffering pause" messages from mythfrontend every
second or so.  The result was very jerky video.

After recompiling sys-libs/glibc, with CFLAGS="-march=pentium3 -O3 -pipe
-fomit-frame-pointer" instead of just the default -O2,  I'm seeing only
one or two "prebuffering pause" messages.  (Usually they'll occur during
switching between virtual desktops.)  I'm stilling seeing an overall
~99% cpu usage (and top shows mythfrontend only using ~60%).

Another option I have, activating interlacing on my device:
# echo 1 > /sys/class/pvrusb2/sn-7435104/ctl_interlace/cur_val

At this point, I'm seeing Mythtv's cpu usage further drop down to an
overall ~30-48%.  (Top shows mythfronted drop to ~20%.)

(One reason I'm seeing an additional 20% cpu spike every 5 seconds is
due to gkrellm2.)

Hauppauge WinTV PVR USB2
Streams mpeg2-ps @ 720x480

--
Roger
http://www.eskimo.com/~roger/index.html
Key fingerprint = 8977 A252 2623 F567 70CD 1261 640F C963 1005 1D61

Tue Aug 9 12:06:46 PDT 2005