malloc in the slow lane

Tim Robbins tjr at freebsd.org
Thu Jul 29 02:37:53 PDT 2004


On Thu, Jul 29, 2004 at 12:22:09PM +0300, Danny Braniss wrote:
> hi,
> 	just came across a 'anomality'. The kernel is -current,
> the same program, compiled under -stable, runs 'fast', while
> the compiled under -current, is slowwwwwwwwwwww.
> 
> According to the UPDATING note, this is supposed to be expected, but
> can't find a fix.
> 
> some data:
> i386-freebsd5.2/memsize:
>         libm.so.2 => /lib/libm.so.2 (0x48077000)
>         libc.so.5 => /lib/libc.so.5 (0x48090000)
> i386-freebsd4.9/memsize:
>         libm.so.2 => /lib/libm.so.2 (0x48078000)
>         libc.so.4 => /usr/lib/compat/libc.so.4 (0x48091000)
> 
> time i386-freebsd5.2/memsize 32
> 0.548u 1.073s 0:01.62 99.3%     25+33211k 0+0io 0pf+0w
> time i386-freebsd4.9/memsize 32
> 0.009u 0.062s 0:00.07 85.7%     32+43957k 0+0io 0pf+0w
> 
> any insights?

The 'J' malloc(3) debugging flag is enabled by default on -CURRENT, but is not
enabled on RELENG_4 or any release branches. Try "ln -sf j /etc/malloc.conf".


Tim


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