programs linked against libpthread have high VSZ

[rwhron]

I noticed that programs that use libpthread appear to use more virtual 
memory than the same program linked against the pth library.  Example
program mp3blaster-3.0:


glibc-2.2.4 with glibc-linuxthreads-2.2.4:

ldd /usr/local/bin/mp3blaster

        libvorbisfile.so.0 => /usr/local/lib/libvorbisfile.so.0 (0x4001f000)
        libvorbis.so.0 => /usr/local/lib/libvorbis.so.0 (0x40024000)
        libncurses.so.5 => /lib/libncurses.so.5 (0x4003a000)
        libpthread.so.0 => /lib/libpthread.so.0 (0x4007d000)
        libstdc++-libc6.2-2.so.3 => /usr/lib/libstdc++-libc6.2-2.so.3 
(0x40091000)
        libm.so.6 => /lib/libm.so.6 (0x400dc000)
        libc.so.6 => /lib/libc.so.6 (0x400ff000)
        libogg.so.0 => /usr/local/lib/libogg.so.0 (0x40222000)
        /lib/ld-linux.so.2 => /lib/ld-linux.so.2 (0x40000000)

Here is mp3blaster at startup.

address@hidden:/usr/src/sources/m# ps aux|egrep 'mp3|VSZ'
USER       PID %CPU %MEM   VSZ  RSS TTY      STAT START   TIME COMMAND
hrandoz  28961  0.1  0.2 10976 1508 tty5     S    19:09   0:00 mp3blaster
hrandoz  28962  0.0  0.2 10976 1508 tty5     S    19:09   0:00 mp3blaster
hrandoz  28963  0.0  0.2 10976 1508 tty5     S    19:09   0:00 mp3blaster

Play a few big mp3's:

ps aux|egrep 'mp3|VSZ'
USER       PID %CPU %MEM   VSZ  RSS TTY      STAT START   TIME COMMAND
hrandoz  28961  0.0  0.8 46356 4320 tty5     S    19:09   0:00 mp3blaster
hrandoz  28962  0.0  0.8 46356 4320 tty5     S    19:09   0:00 mp3blaster
hrandoz  28963  3.4  0.8 46356 4320 tty5     S    19:09   0:04 mp3blaster
hrandoz  28977  0.3  0.8 46356 4320 tty5     S    19:11   0:00 mp3blaster

See how the VSZ got big?

Actually, I didn't play a bunch of mp3's.  I just started to play some
mp3's and hit <Enter> to restart, etc, etc.  If I was patient and actually
listened to the mp3's, the same behavior would be seen.

glibc-2.2.4 with pth-1.40:
------

Recompile mp3blaster:

./configure --disable-nls --with-pthreads=no --with-pth=yes


ldd /usr/local/bin/mp3blaster

        libvorbisfile.so.0 => /usr/local/lib/libvorbisfile.so.0 (0x4001f000)
        libvorbis.so.0 => /usr/local/lib/libvorbis.so.0 (0x40024000)
        libncurses.so.5 => /lib/libncurses.so.5 (0x4003a000)
        libpth.so.14 => /usr/lib/libpth.so.14 (0x4007d000)
        libstdc++-libc6.2-2.so.3 => /usr/lib/libstdc++-libc6.2-2.so.3 
(0x4008f000)
        libm.so.6 => /lib/libm.so.6 (0x400da000)
        libc.so.6 => /lib/libc.so.6 (0x400fd000)
        libogg.so.0 => /usr/local/lib/libogg.so.0 (0x40220000)
        /lib/ld-linux.so.2 => /lib/ld-linux.so.2 (0x40000000)


Before playing anything:

USER       PID %CPU %MEM   VSZ  RSS TTY      STAT START   TIME COMMAND
hrandoz  30442  0.0  0.2  2940 1504 tty5     S    19:16   0:00 mp3blaster

Note, there is only one thread.

After playing a bunch of mp3's:

address@hidden:/usr/src/sources/m/mp3blaster-3.0# ps aux|egrep 'VSZ|mp3'
USER       PID %CPU %MEM   VSZ  RSS TTY      STAT START   TIME COMMAND
hrandoz  30442  4.1  0.3  3004 1744 tty5     S    19:16   0:05 mp3blaster

It's much smaller.


I do note that under extreme load, mp3blaster skips more with pth than
glibc-linuxthreads.


Another program compiled with libpthread that has a larger VSZ than I 
expected is iplog-2.3.3:

USER       PID %CPU %MEM   VSZ  RSS TTY      STAT START   TIME COMMAND
root        39  0.0  0.0 26100  144 ?        S    02:10   0:00 /usr/sbin/iplog
root        40  0.0  0.0 26100  144 ?        S    02:10   0:00 /usr/sbin/iplog
root        42  0.0  0.0 26100  144 ?        S    02:10   0:00 /usr/sbin/iplog
root        43  0.0  0.0 26100  144 ?        S    02:10   0:00 /usr/sbin/iplog
root        44  0.0  0.0 26100  144 ?        S    02:10   0:00 /usr/sbin/iplog
-- 
Randy Hron