Extremely poor performance crunching random numbers under PIV-FC5

[Andy Green]

BankHacker wrote:

> Looking for information about "linux-gate.so.1" I have found this webpage:
> 
>     http://www.trilithium.com/johan/2005/08/linux-gate/

> I think this could be the reason for the slowdown in my case because
> symptoms match. My program is invoking 10 million system calls for the
> first random test and it happens only in the dynamic version. My CPU
> is an Intel Pentium IV.

Ahaha, so if I understand you the strace output is huge for the dynamic 
one and smaller for the static one?

Can you post an example of one of the "10 million" syscalls that is 
present in the strace output for the dynamic case (if I understood you 
correctly)?

> My glibc version is 2.4-8:
> 
> # rpm -qa | grep glibc
>     glibc-kernheaders-3.0-5.2
>     glibc-common-2.4-8
>     glibc-headers-2.4-8
>     glibc-2.4-8
>     glibc-devel-2.4-8
> 
> Do you think this could be the cause. How to fix it?
> 
> Thanks!

There are some magic things down

/proc/sys/kernel/

that you might want to meddle with to see if they affect the situation.  Eg

echo "0" >/proc/sys/kernel/randomize_va_space
echo "0" >/proc/sys/kernel/exec-shield

Another idea, perhaps to to give a static libm and keep the dynamic libc 
stuff  eg

gcc blah.c /usr/lib/libm.a

not sure if that will work but worth a try.  Then the ldd for the 
resulting binary should no longer reference libm.

-Andy
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