svn commit: r228857 - in head/usr.bin: . csup

[Doug Barton]

On 12/26/2011 14:51, Steve Kargl wrote:
> On Mon, Dec 26, 2011 at 12:43:07PM -0800, Doug Barton wrote:
>> On 12/26/2011 02:28, Marius Strobl wrote:
>>> On Sat, Dec 24, 2011 at 01:36:18PM -0800, Doug Barton wrote:
>>>> On 12/24/2011 04:16, Marius Strobl wrote:
>>>>>   On FreeBSD just use the MD5 implementation of libmd rather than that of
>>>>>   libcrypto so we don't need to relinquish csup when world is built without
>>>>>   OpenSSL.
>>>>
>>>> Did you benchmark this at all? I agree that keeping csup available
>>>> absent openssl is a good goal, but csup is a prototypical "tool that
>>>> does the same thing many thousands of times" so even tiny regressions
>>>> could add up to a large cost in wall clock time.
>>>
>>> Well, in a real world test updating the same base on an amd64 machine
>>> connected to the Internet
>>
>> Adding a network connection to the test is almost certainly going to
>> obscure the results beyond utility.
> 
> Given that the majority of FreeBSD users will be pulling code
> from the internet, this seems to be the most relevant test.

Sorry if I wasn't clear. The change was to how the md5 portion of csup
is linked. In order to isolate the effects of that change you have to
remove everything that isn't related to that change.

But this is regression testing 101, so I'm sure that you know that already.

>> The appropriate way to test this
>> would be to create a binary out of the md5 routine in csup, and link it
>> alternately with libcrypto and libmd. Then for each version run it
>> against the src tree (or ports, either way) 10 times. Discard the first
>> and last, and then plot the results with ministat.
> 
> The proper way to test the libmd vs libcrypto versions of
> the md5 routines is to use a profiler.  

That'll give you a good view of where the performance bottlenecks are if
it turns out that libmd is actually slower, sure. But the interesting
question in terms of this change is the effect on wall clock time, since
that's what users are going to see.

> Of course, one might ask the question on how the use of
> libmd effects the majority of FreeBSD users (ie., not FreeBSD
> developers).  Does the majority run csup hourly?  Daily?
> Weekly? 

For those that use csup, I imagine that they use it at least daily. But
that's not the point.

> For a utility seldomly run be the majority of FreeBSD
> users, Doug, you seem to be wasting Marius's time.

How often it's used isn't really relevant to whether or not introducing
a pessimization is worth it. In any case I didn't ask him to back it
out, I only asked to have it be an option if it turns out that libmd is
slower.

I understand that what you're really trying to do here is to take a shot
at me relative to my assertion that profiled libs should be off by
default. If you're going to respond in kind to every message I send it's
going to get boring really quick.


Doug

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