svn commit: r292955 - head/lib/libmd

Jonathan T. Looney jtl at freebsd.org
Thu Dec 31 18:46:39 UTC 2015


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




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