Performance Tracker project update

[Kris Kennaway]

Kris Kennaway wrote:

>>> P.S. If I understand correctly, the float test shows a regression?  
>>> The metric is calculations/second, so higher = better?
>>
>> The documentation on Unixbench is scarce, but I would think so.
> 
> Interesting.  Some candidate changes from 2007-10-02:
> 
>   Modified files:
>     contrib/gcc          opts.c
>   Log:
>   Do not imply -ftree-vrp with -O2 and above.  One must implicitly specify
>   '-ftree-vrp' if one wants it.
>   Some bad code generation has been tracked to -ftree-vrp.  jdk1{5,6} are
>   notable examples.

OK, so it was this one.  The other interesting events seem to be:

2007-10-20: drop in super-smack performance and context switch 
benchmarks.  This is due to the switch from SCHED_4BSD to SCHED_ULE 
(super-smack is largely a context switch benchmark due to retarded 
design).  There are uncommitted patches that reduce ULE context switch 
overhead though, so it will be interesting to see how they affect this.

2007-12-30: file read/pipe read/pipe ping-pong/syscall overhead 
performance increases.  This is due to Jeff's lockless struct file 
changes (syscall overhead is only affected because unixbench uses the 
dup2() syscall which is not in fact just a measure of syscall overhead 
but now has reduced non-syscall cost).

Kris