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

Doug Barton dougb at FreeBSD.org
Mon Dec 26 20:43:27 UTC 2011


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. 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.

> If we really cared about the MD5 performance of applications linked
> against libmd (including md5(1)), we should just optimize that MD5
> implementation rather than working around it.

If it turns out that it's slower, that's a valid option as long as it
happens soon'ish. :)

> Also for csup, fixing the problem that is causing it to fetch whole
> files over and over again likely would improve its performance way
> more than using a different MD5 implementation could do.

"There are other problems with this program" is not a good reason to add
a pessimization. But let's find out if it is a pessimization before we
worry about that.


Doug

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