Posted by Gerard Samuel on 02/18/05 04:18

Jason Barnett wrote:

>Gerard Samuel wrote:
>...
>
>
>>>>Im trying to determine if md5() would be the fastest,
>>>>*cheapest* solution.
>>>>
>>>>
>...
>
>
>>What Im looking for is something where the generated hashes can
>>be reproduced.
>>For example, md5('foo') today, will be equal to md5('foo') tomorrow.
>>Thanks
>>
>>
>
>AFAIK crc32() is the fastest hashing function in PHP. I don't have
>actual results on hand still, but I created a filesystem plugin that
>auto-generates hashes for each file in a directory. crc32() was faster
>than md5() and sha1().
>
>FYI the benchmarking that I did was for a Windows XP system... YMMV
>

I normally profile with apd, but it only measures in the hundredth of
a second.
So I used getrusage() & memory_get_usage() functions to *unscientifically*
profile md5()/sha1()/crc32() on FreeBSD 5.3.

I ran a for loop 75 times, hashing the constant __FILE__
These are an average of 5 runs ->
----
md5:
Usertime -> 784.2 µsec
Systemtime -> 72.2 µsec
Memory -> 120.0 bytes

sha1:
Usertime -> 846.8 µsec
Systemtime -> 150.2 µsec
Memory -> 80.0 bytes

crc32:
Usertime -> 194.8 µsec
Systemtime -> 54.2 µsec
Memory -> 80.0 bytes

Can you shed some light on that code,
that you're using for the filesystem plugin?

Thanks

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