Awk vs. grep (grep is too slow?)

# Links
Script: http://pastebin.com/PJ2VfqN4
Result: http://tinypic.com/r/303a4iv/7

--

# environment
GNU Awk 3.1.8
GNU grep 2.6.3

$ cat /proc/cpuinfo
processor	: 0
vendor_id	: GenuineIntel
cpu family	: 6
model		: 23
model name	: Celeron(R) Dual-Core CPU       T3000  @ 1.80GHz
stepping	: 10
cpu MHz		: 1795
cache size	: 1024 KB
fpu		: yes
fpu_exception	: yes
cpuid level	: 13
wp		: yes
flags		: fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe pni dtes64 monitor ds_cpl tm2 ssse3 cx16 xtpr pdcm xsave osxsave lahf_lm
TLB size	: 0 4K pages
clflush size	: 64
cache_alignment	: 64
address sizes	: 36 bits physical, 48 bits virtual
power management:

processor	: 1
vendor_id	: GenuineIntel
cpu family	: 6
model		: 23
model name	: Celeron(R) Dual-Core CPU       T3000  @ 1.80GHz
stepping	: 10
cpu MHz		: 1795
cache size	: 1024 KB
fpu		: yes
fpu_exception	: yes
cpuid level	: 13
wp		: yes
flags		: fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe pni dtes64 monitor ds_cpl tm2 ssse3 cx16 xtpr pdcm xsave osxsave lahf_lm
TLB size	: 0 4K pages
clflush size	: 64
cache_alignment	: 64
address sizes	: 36 bits physical, 48 bits virtual
power management:

--

# make src.txt
wget http://www.kernel.org/pub/linux/kernel/v2.6/linux-2.6.39.1.tar.bz2
tar xf linux-2.6.39.1.tar.bz2 --wildcards '*.c' -O >src.txt

--

## merge time.txt with cmd.txt
awk '/./ { print; next };
     { print; if (!("" p)) getline p < "time.txt";
       print p; while ((getline q < "time.txt") > 0) { if (p == q) break; print q }
       print }' <cmd.txt >ttime.txt

## for gnuplot
awk '/^# result$/ { b = !b }; !b { next };
     $1 == "time" { t[0] = t[1]; if (/awk/) { sub(/^.*}; \//, "\"/"); sub(/ { .*$/, "\"") }
                                 else gsub(/^.*\$I | >\/.*$/, "\""); gsub(/\\/, "&&"); t[1] = $0; next };
     /^user/ { split($2, u, "m"); s[0] = s[1]; s[1] = 60 * u[1] + u[2]; next };
     /^for/ { if (t[0]) { p(c, s); print ORS } sub(/[^0-9]+/, ""); print "#", +$0 };
     /^[0-9]+$/ { if (/^0$/) p("\"Lines\"", t); else p(c, s); c = $0 };
     END { p(c, s) };
     function p(x, y) { print x, y[0], y[1] }' ttime.txt >gp.dat

--

# measure execution time
for ((N=3000000,I=0; I<=100; I+=20)); do echo $I 1>&2; time head -n$N src.txt |awk 'BEGIN { L = '$I'; b = L + 1; n = L + 2; i = j = 0; s = 2; }; /regex/ { if (L && s == 1) print "--"; while (i != j) { print a[i++]; if (i == b) i = 0 } n = s = 0 }; n > L { a[j++] = $0; if (j == b) j = 0; if (i == j) { i++; if (i == b) i = 0; if (!s) s++ } next }; n++ <= L' >/dev/null; time head -n$N src.txt |grep -C $I 'regex' >/dev/null; done 2>>time.txt

--

# test script
for ((N=3000000,I=0; I<=100; I+=50)); do
  echo $I 1>&2
  time head -n$N src.txt |awk 'BEGIN { L = '$I'; (snip.) }; /regex/ { (snip.) }; n++ <= L' >/dev/null
  time head -n$N src.txt |grep -C $I 'regex' >/dev/null
done 2>time.txt

--

# result

for ((N=3000000,I=0; I<=100; I+=20)); do
  echo $I 1>&2
  time head -n$N src.txt |awk 'BEGIN { L = '$I'; (snip.) }; /test/ { (snip.) }; n++ <= L' >/dev/null
  time head -n$N src.txt |grep -C $I test >/dev/null
done 2>time.txt

0

real	0m8.646s
user	0m8.673s
sys	0m0.482s

real	0m0.790s
user	0m0.607s
sys	0m0.450s
20

real	0m9.295s
user	0m9.266s
sys	0m0.451s

real	0m0.778s
user	0m0.685s
sys	0m0.373s
40

real	0m9.533s
user	0m9.873s
sys	0m0.483s

real	0m0.765s
user	0m0.685s
sys	0m0.388s
60

real	0m9.635s
user	0m9.717s
sys	0m0.497s

real	0m0.768s
user	0m0.733s
sys	0m0.419s
80

real	0m9.696s
user	0m9.780s
sys	0m0.341s

real	0m0.793s
user	0m0.747s
sys	0m0.435s
100

real	0m9.766s
user	0m9.765s
sys	0m0.498s

real	0m0.791s
user	0m0.654s
sys	0m0.544s

for ((N=3000000,I=0; I<=100; I+=20)); do
  echo $I 1>&2
  time head -n$N src.txt |awk 'BEGIN { L = '$I'; (snip.) }; /test.*test/ { (snip.) }; n++ <= L' >/dev/null
  time head -n$N src.txt |grep -C $I 'test.*test' >/dev/null
done 2>>time.txt

0

real	0m8.549s
user	0m8.517s
sys	0m0.482s

real	0m0.851s
user	0m0.794s
sys	0m0.419s
20

real	0m9.341s
user	0m9.125s
sys	0m0.357s

real	0m0.925s
user	0m0.920s
sys	0m0.497s
40

real	0m9.610s
user	0m9.594s
sys	0m0.497s

real	0m0.843s
user	0m0.810s
sys	0m0.466s
60

real	0m9.671s
user	0m9.608s
sys	0m0.357s

real	0m0.858s
user	0m0.669s
sys	0m0.560s
80

real	0m9.707s
user	0m9.842s
sys	0m0.451s

real	0m0.856s
user	0m0.779s
sys	0m0.466s
100

real	0m9.774s
user	0m9.826s
sys	0m0.561s

real	0m0.846s
user	0m0.763s
sys	0m0.373s

for ((N=30000,I=0; I<=100; I+=20)); do
  echo $I 1>&2
  time head -n$N src.txt |awk 'BEGIN { L = '$I'; (snip.) }; /./ { (snip.) }; n++ <= L' >/dev/null
  time head -n$N src.txt |grep -C $I . >/dev/null
done 2>>time.txt

0

real	0m0.168s
user	0m0.077s
sys	0m0.046s

real	0m50.856s
user	0m50.169s
sys	0m0.092s
20

real	0m0.171s
user	0m0.046s
sys	0m0.061s

real	0m50.712s
user	0m49.998s
sys	0m0.076s
40

real	0m0.190s
user	0m0.077s
sys	0m0.046s

real	0m50.489s
user	0m50.216s
sys	0m0.030s
60

real	0m0.181s
user	0m0.078s
sys	0m0.046s

real	0m51.034s
user	0m50.294s
sys	0m0.045s
80

real	0m0.162s
user	0m0.062s
sys	0m0.031s

real	0m50.549s
user	0m50.076s
sys	0m0.045s
100

real	0m0.171s
user	0m0.061s
sys	0m0.062s

real	0m50.535s
user	0m50.091s
sys	0m0.030s

for ((N=30000,I=0; I<=100; I+=20)); do
  echo $I 1>&2
  time head -n$N src.txt |awk 'BEGIN { L = '$I'; (snip.) }; /.*/ { (snip.) }; n++ <= L' >/dev/null
  time head -n$N src.txt |grep -C $I '.*' >/dev/null
done 2>>time.txt

0

real	0m0.153s
user	0m0.077s
sys	0m0.076s

real	0m59.338s
user	0m58.703s
sys	0m0.045s
20

real	0m0.164s
user	0m0.077s
sys	0m0.045s

real	0m59.392s
user	0m58.608s
sys	0m0.030s
40

real	0m0.165s
user	0m0.077s
sys	0m0.062s

real	1m1.078s
user	0m59.139s
sys	0m0.030s
60

real	0m0.174s
user	0m0.078s
sys	0m0.061s

real	0m59.714s
user	0m58.952s
sys	0m0.076s
80

real	0m0.164s
user	0m0.046s
sys	0m0.060s

real	0m59.242s
user	0m58.796s
sys	0m0.092s
100

real	0m0.164s
user	0m0.046s
sys	0m0.061s

real	1m1.563s
user	0m59.249s
sys	0m0.107s

for ((N=3000000,I=0; I<=100; I+=20)); do
  echo $I 1>&2
  time head -n$N src.txt |awk 'BEGIN { L = '$I'; (snip.) }; / / { (snip.) }; n++ <= L' >/dev/null
  time head -n$N src.txt |grep -C $I ' ' >/dev/null
done 2>>time.txt

0

real	0m9.239s
user	0m7.206s
sys	0m0.529s

real	0m2.661s
user	0m2.277s
sys	0m0.606s
20

real	0m6.663s
user	0m5.786s
sys	0m0.591s

real	0m3.483s
user	0m3.025s
sys	0m0.451s
40

real	0m6.886s
user	0m6.051s
sys	0m0.482s

real	0m3.457s
user	0m2.901s
sys	0m0.546s
60

real	0m6.546s
user	0m5.864s
sys	0m0.623s

real	0m3.809s
user	0m3.306s
sys	0m0.264s
80

real	0m6.744s
user	0m6.006s
sys	0m0.684s

real	0m4.726s
user	0m3.072s
sys	0m0.560s
100

real	0m6.587s
user	0m5.911s
sys	0m0.561s

real	0m4.014s
user	0m3.447s
sys	0m0.357s

for ((N=3000000,I=0; I<=100; I+=20)); do
  echo $I 1>&2
  time head -n$N src.txt |awk 'BEGIN { L = '$I'; (snip.) }; / ./ { (snip.) }; n++ <= L' >/dev/null
  time head -n$N src.txt |grep -C $I ' .' >/dev/null
done 2>>time.txt

0

real	0m7.628s
user	0m7.066s
sys	0m0.561s

real	0m9.883s
user	0m8.938s
sys	0m0.544s
20

real	0m6.658s
user	0m5.803s
sys	0m0.684s

real	0m10.163s
user	0m9.531s
sys	0m0.482s
40

real	0m7.104s
user	0m6.097s
sys	0m0.514s

real	0m10.673s
user	0m9.858s
sys	0m0.669s
60

real	0m7.071s
user	0m5.989s
sys	0m0.466s

real	0m10.524s
user	0m9.702s
sys	0m0.654s
80

real	0m6.198s
user	0m5.756s
sys	0m0.559s

real	0m10.446s
user	0m9.936s
sys	0m0.512s
100

real	0m6.310s
user	0m5.926s
sys	0m0.466s

real	0m10.653s
user	0m9.858s
sys	0m0.434s

for ((N=3000000,I=0; I<=100; I+=20)); do
  echo $I 1>&2
  time head -n$N src.txt |awk 'BEGIN { L = '$I'; (snip.) }; / ?[-+=*/~|^&] ?/ { (snip.) }; n++ <= L' >/dev/null
  time head -n$N src.txt |grep -C $I ' \?[-+=*/~|^&] \?' >/dev/null
done 2>>time.txt

0

real	0m7.522s
user	0m7.581s
sys	0m0.451s

real	0m1.472s
user	0m1.480s
sys	0m0.435s
20

real	0m5.794s
user	0m5.879s
sys	0m0.467s

real	0m2.237s
user	0m2.324s
sys	0m0.357s
40

real	0m5.886s
user	0m5.896s
sys	0m0.514s

real	0m2.328s
user	0m2.433s
sys	0m0.420s
60

real	0m5.898s
user	0m5.833s
sys	0m0.528s

real	0m2.394s
user	0m2.402s
sys	0m0.483s
80

real	0m6.228s
user	0m6.037s
sys	0m0.420s

real	0m2.345s
user	0m2.293s
sys	0m0.623s
100

real	0m5.733s
user	0m5.740s
sys	0m0.529s

real	0m2.380s
user	0m2.323s
sys	0m0.590s

for ((N=3000000,I=0; I<=100; I+=20)); do
  echo $I 1>&2
  time head -n$N src.txt |awk 'BEGIN { L = '$I'; (snip.) }; / [_A-Za-z][^ ]/ { (snip.) }; n++ <= L' >/dev/null
  time head -n$N src.txt |grep -C $I ' [_A-Za-z][^ ]' >/dev/null
done 2>>time.txt

0

real	0m20.183s
user	0m19.390s
sys	0m0.482s

real	0m12.193s
user	0m11.917s
sys	0m0.560s
20

real	0m18.113s
user	0m17.331s
sys	0m0.575s

real	0m13.256s
user	0m12.900s
sys	0m0.513s
40

real	0m18.065s
user	0m17.362s
sys	0m0.405s

real	0m13.086s
user	0m12.853s
sys	0m0.389s
60

real	0m17.816s
user	0m17.315s
sys	0m0.482s

real	0m13.046s
user	0m12.838s
sys	0m0.669s
80

real	0m17.557s
user	0m17.283s
sys	0m0.514s

real	0m13.439s
user	0m12.900s
sys	0m0.419s
100

real	0m17.735s
user	0m17.378s
sys	0m0.466s

real	0m12.999s
user	0m12.947s
sys	0m0.466s