7.0 CPU and Memory Performance

[Kris Kennaway]

Tim Traver wrote:
> 
> Robert Watson wrote:
>> On Tue, 12 Aug 2008, Tim Traver wrote:
>>
>>> I have recently had the opportunity to upgrade a few servers from old
>>> versions of 5.4 to 7.0, and have seen some interesting data. Before
>>> doing this, I wanted to take some benchmarks to see how the scripts
>>> that I would run would fare between the two versions, and the results
>>> are somewhat confusing...
>> There are potentially a lot of variables here, you migh want to try
>> fiddling with the following and see what difference it makes:
>>
>> (1) Try both 4BSD and ULE in 7.0 -- they have different properties,
>> and at the
>>     very least it would be nice to see what impact it has.
>>
>> (2) Statically compile the 5.4 binary, and run the same binary on both
>> 5.4 and
>>     7.0 -- there have been lots of compiler changes, which might be
>> relevant.
>>
>> Also, can you confirm that you're running either 32-bit or 64-bit
>> kernels consistently on both versions of FreeBSD?
>>
>> Robert N M Watson
>> Computer Laboratory
>> University of Cambridge
>>
>>
> Robert,
> 
> ok, I looked and it looks like the port compiles statically, and I was
> able to grab the binary from the old disk and move it over to the new one...
> 
> here is info now on how it is linked :
> 
> [root ~]# ldd ubench.5.4
> ubench.5.4:
>         libm.so.3 => /usr/local/lib/compat/libm.so.3 (0x2807e000)
>         libc.so.5 => /usr/local/lib/compat/libc.so.5 (0x28099000)
> [root ~]# ldd /usr/local/bin/ubench
> /usr/local/bin/ubench:
>         libm.so.5 => /lib/libm.so.5 (0x2807f000)
>         libc.so.7 => /lib/libc.so.7 (0x28094000)
> 
> where ubench is the locally compiled one...
> 
> For reference, here are the old stats
> FreeBSD 5.4 - CPU 112,721 - MEM - 146,483
> FreeBSD 7.0 - CPU 177,339 - MEM - 95,920
> 
> And here is the run of the ubench.5.4 binary:
> FreeBSD 7.0 - CPU 139,623 - MEM - 207,180
> 
> And a rerun of the FreeBSD 7.0 ubench making sure there is absolutely no activity on the box
> FreeBSD 7.0 - CPU 200,562 - MEM - 107,695
> 
> That run is a little better than the previous one, but there seems to still be quite a difference in the memory tests...
> 
> Does that show anything ????

It shows that if there is a difference it is probably in userland, not 
the kernel.  The obvious guess is the new malloc in 7.0.  As for whether 
it indicates a bug, someone would have to look more closely at what 
ubench does.  The author's description of his benchmark doesn't inspire 
confidence: it does "rather senseless memory allocation and memory to 
memory copying operations for another 3 mins concurrently using several 
processes".

Kris