svn commit: r292955 - head/lib/libmd

[Allan Jude]

On 2015-12-31 13:50, Allan Jude wrote:
> On 2015-12-31 13:32, Jonathan T. Looney wrote:
>> On 12/31/15, 2:15 AM, "Allan Jude" <allanjude at freebsd.org> wrote:
>>
>>> It seems these problems also slow things down, a lot:
>>>
>>> # time md5 /media/md5test/bigdata
>>> MD5 (/media/md5test/bigdata) = 6afad0bf5d8318093e943229be05be67
>>> 4.310u 3.476s 0:07.79 99.8%     20+167k 0+0io 0pf+0w
>>> # time env LD_PRELOAD=/usr/obj/media/svn/md5/head/tmp/lib/libmd.so
>>> /usr/obj/media/svn/md5/head/sbin/md5/md5 /media/md5test/bigdata
>>> MD5 (/media/md5test/bigdata) = 6afad0bf5d8318093e943229be05be67
>>> 4.133u 0.354s 0:04.49 99.7%     20+167k 1+0io 0pf+0w
>>>
>>> (file is fully cached in ZFS ARC, dd reads it at 11GB/s)
>>>
>>> Will investigate more tomorrow.
>>
>> md5 will be slower than dd due to the extra processing it needs to do to
>> generate the hash. I suspect that explains the difference you're seeing
>> between those utilities.
>>
>> Jonathan
>>
>>
>>
> 
> Sorry, you missed my point here.
> 
> I replaced MDXFile() with the implementation included in my earlier
> email. Using the newer libmd with that code, cut the time to md5 the
> SAME data down a lot. I need to do a more scientific test on a box that
> isn't doing other stuff still though.
> 
> The comment about dd doing 11GB/s, was just to clarify that I wasn't
> reading the file from disk, which would introduce other variables.
> 

I found the cause of my bogus benchmark, the world on my test machine
was just old enough to be missing jmg@'s bufsize patch.

Now the difference is about 1 second on a 2GB file, so ignore my
foolishness.

-- 
Allan Jude

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