Poor mans dmenu benchmark

I wanted to know how responsive dmenu and awk, sort, uniq are on a 50MB file (625000 entries of 80 1-byte chars each).

generate file:

echo "Creating dummy file of 50MB in size (625000 entries of 80chars)"
echo "Note: this takes about an hour and a half"
for i in `seq 1 625`
        echo "Iteration $i of 625 ( $entries_per_iteration each )"
        for j in `seq 1 $entries_per_iteration`
                echo "`date +'%Y-%m-%d %H:%M:%S'` `date +%s`abcdefhijklmno`date +%s | md5sum`" >> ./dummy_history_file

measure speed:

echo "Plain awk '{print \$3}':"
time awk '{print $3}' dummy_history_file >/dev/null

echo "awk + sort"
time awk '{print $3}' dummy_history_file | sort >/dev/null
echo "awk + sort + uniq"
time awk '{print $3}' dummy_history_file | sort | uniq >/dev/null

echo "Plain dmenu:"
dmenu < dummy_history_file
echo "awked into dmenu:"
awk '{print $3}' dummy_history_file | dmenu
echo "awk + sort + uniq into dmenu:"
awk '{print $3}' dummy_history_file | sort | uniq | dmenu

I ran the test twice about an half hour after generating the file, so in the first run, the first awk call may have been affected by a no longer complete Linux block cache.
(I also edited the output format a bit)
Run 1:

Plain awk '{print $3}':
real	0m1.253s
user	0m0.907s
sys	0m0.143s

awk + sort:
real	0m3.696s
user	0m1.887s
sys	0m0.520s

awk + sort + uniq:
real	0m15.768s
user	0m12.233s
sys	0m0.820s

Plain dmenu:
awked into dmenu:
awk + sort + uniq into dmenu:

Run 2

Plain awk '{print $3}':
real	0m1.223s
user	0m0.923s
sys	0m0.107s

awk + sort:
real	0m2.799s
user	0m1.910s
sys	0m0.553s

awk + sort + uniq:
real	0m16.387s
user	0m12.019s
sys	0m0.787s
Plain dmenu:
awked into dmenu:
awk + sort + uniq into dmenu:

Not too bad. It's especially uniq who seems to cause a lot of slowdown. (in this dummy test file, are entries are unique. If there were lots of dupes, the results would probably be different, but I suspect that uniq always needs some time to do its work, dupes or not). The real bottleneck seems to be raw cpu power. Not storage bandwidth at all since Linux caches it. If uncached, I estimate the sequential read would take 1.5 seconds or so. (about 30MB/s on common hard disks)

Once the stuff gets piped into dmenu, there is a little lag but it's reasonably responsive imho.
Test performed on an athlon xp @ 2GHz. 1 GB of memory. There were some other apps running, not a very professional benchmark but you get the idea :)