7.0 CPU and Memory Performance

[Tim Traver]

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,

Yes, I agree, there are a lot of moving variables.

1) I did try the 4BSD scheduler too, and found that it was actually much 
worse. It may be because the ubench will spawn a few processes, and ULE 
is better at SMP than 4BSD is, but I don't know...

2) Unfortunately, I have now already replaced the 5.4 machines with 7.0. 
I tried to take the benchmarks before I rebuilt things. Like I said, I'm 
sure my methods were flawed...

These were both compiled with the 32 bit code...

Is there anything that I can do on this latest 7.0 box that might be 
useful information???

Thanks,

Tim.


>>
>> I tried to get as many ducks in a row before posting this, cause i 
>> don't want to waste any of the developers precious time, but I can't 
>> guarantee that my methods were not flawed.
>>
>> For simplicity, I used a port called ubench (the latest version 0.3, 
>> which I know is quite old) to get the following numbers :
>>
>> Since I was doing this on the same machine, with completely different 
>> builds (not simply a compile upgrade, but a full install), I figure 
>> it doesn't really matter what kind of machine it is, but just for 
>> grins, it is a Dual Opteron with 2GB of memory in it, compiled with 
>> the i386 confs.
>>
>> The 7.0 is compiled with the ULE scheduler...
>>
>> The following are averages of at least 5 runs :
>>
>> FreeBSD 5.4 - CPU 112,721 - MEM - 146,483
>> FreeBSD 7.0 - CPU 177,339 - MEM - 95,920
>>
>> Now, I really don't know exactly what the ubench program is doing, 
>> but I think the description says that it is doing random integer and 
>> floating point operations for the CPU tests, and random memory 
>> allocation and copying for the memory test.
>>
>> So, can we explain the difference???? It looks like the latest SMP 
>> code allows it to process more operations, but what happened to the 
>> memory operations????
>>
>> Just to get an idea of what this was going to do to my scripts, I 
>> tried some benchmarks for those as well.
>>
>> I tried to run a PHP script using php 4.4.7 and got the following 
>> results :
>>
>> Using "time php index.php" to get the real time :
>>
>> FreeBSD 5.4 - 0.290 seconds
>> FreeBSD 7.0 - 0.335 seconds
>>
>> So, do the slower memory operations cause that difference in the real 
>> time it takes to run that script???
>>
>> Thanks,
>>
>> Tim.
>>
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