On Sun, 09 Dec 2012 21:45:03 +0100 Jim Meyering <j...@meyering.net> wrote:
> Thanks for the patch. > This is large enough that you'll have to file a copyright assignment. > For details, see the "Copyright assignment" section in the file > named HACKING. Fine. > Have you considered performance in the common case? > I suspect that a byte or field number larger than 1000 is > not common. That is why, in the FIXME comment above, > I suggested to use an adaptive approach. I had the feeling > (don't remember if I profiled it) that testing a bit per > input field would be more efficient than an in-range test. Yes, it was the first thing I checked. And there's no performance loss. > If you construct test cases and gather timing data, please do so > in a reproducible manner and include details when you report back, > so we can compare on different types of systems. Here are my benchmarks: OS: Parabola GNU/linux-libre (linux-libre v3.6.8-1) Compiler: GCC 4.7.2 Cflags: -O2 LANG: C CPU: Intel Core Duo (1.86 GHz) (L1 Cache 64KiB) (L2 Cache 2MiB) Main memory: - Bank 0: DIMM DRAM Synchronous (1GiB) (width 64 bits) - Bank 1: DIMM DRAM Synchronous (1GiB) (width 64 bits) NOTE: information gathered with `lshw'. Summary (see the attached file for complete data): ### small ranges cut-pre: 0:01.84 cut-post: 0:01.36 cut-split: 0:01.25 ### bigger ranges cut-pre: 0:11.74 cut-post: 0:09.20 cut-split: 0:07.91 *** ### fields cut-pre: 0:02.90 cut-post: 0:02.68 cut-split: 0:02.85 ### --output-delimiter cut-pre: 0:02.90 cut-post: 0:02.74 cut-split: 0:02.80 NOTES: cut-pre is the current implementation and was compiled from commit ec48beadf. cut-post was compiled after applying the above patch to commit ec48beadf. cut-split was compiled after applying the `split-print_kth' patch to commit ec48beadf. The main advantages cames from splitting `print_kth' into two separate functions, so now `print_kth' does fewer checks. Best regards, Cojocaru Alexandru
OS: Parabola GNU/linux-libre (linux-libre v3.6.8-1) Compiler: GCC 4.7.2 Cflags: -O2 LANG: C CPU: Intel Core Duo (1.86 GHz) (L1 64KiB) (L2 2MiB) Main memory: - Bank 0: DIMM DRAM Synchronous (1GiB) (width 64 bits) - Bank 1: DIMM DRAM Synchronous (1GiB) (width 64 bits) NOTE: information gathered with `lshw'. bash$ ./cut-pre 2> /dev/null # try not to count caching of shared libraries ### small ranges bash$ for i in `seq 1 1000000`; do echo "abcdfeg" >> big-file; done bash$ for i in 1 2 3; do /usr/bin/time ./cut-pre -b1,3 big-file > /dev/null; echo ; done 1.72user 0.11system 0:01.84elapsed 99%CPU (0avgtext+0avgdata 568maxresident)k 0inputs+0outputs (0major+168minor)pagefaults 0swaps 1.75user 0.08system 0:01.84elapsed 99%CPU (0avgtext+0avgdata 572maxresident)k 0inputs+0outputs (0major+168minor)pagefaults 0swaps 1.76user 0.07system 0:01.84elapsed 99%CPU (0avgtext+0avgdata 568maxresident)k 0inputs+0outputs (0major+167minor)pagefaults 0swaps bash$ for i in 1 2 3; do /usr/bin/time ./cut-post -b1,3 big-file > /dev/null; echo; done 1.23user 0.12system 0:01.36elapsed 99%CPU (0avgtext+0avgdata 560maxresident)k 0inputs+0outputs (0major+165minor)pagefaults 0swaps 1.25user 0.09system 0:01.36elapsed 99%CPU (0avgtext+0avgdata 560maxresident)k 0inputs+0outputs (0major+165minor)pagefaults 0swaps 1.25user 0.09system 0:01.36elapsed 99%CPU (0avgtext+0avgdata 556maxresident)k 0inputs+0outputs (0major+164minor)pagefaults 0swaps bash$ for i in 1 2 3; do /usr/bin/time ./cut-split -b1,3 big-file > /dev/null; echo ; done 1.15user 0.09system 0:01.25elapsed 99%CPU (0avgtext+0avgdata 572maxresident)k 0inputs+0outputs (0major+168minor)pagefaults 0swaps 1.15user 0.08system 0:01.25elapsed 99%CPU (0avgtext+0avgdata 568maxresident)k 0inputs+0outputs (0major+167minor)pagefaults 0swaps 1.14user 0.10system 0:01.25elapsed 99%CPU (0avgtext+0avgdata 568maxresident)k 0inputs+0outputs (0major+167minor)pagefaults 0swaps ### bigger ranges bash$ yes $(for i in $(seq 1 100000); do echo -n a; done) | dd of=big-lines ibs=100001 count=10000 iflag=fullblock bash$ for i in 1 2 3; do /usr/bin/time ./cut-pre -b50-100,101-105,9999 big-lines > /dev/null; echo; done 11.01user 0.70system 0:11.74elapsed 99%CPU (0avgtext+0avgdata 572maxresident)k 0inputs+0outputs (0major+168minor)pagefaults 0swaps 11.02user 0.70system 0:11.74elapsed 99%CPU (0avgtext+0avgdata 576maxresident)k 0inputs+0outputs (0major+169minor)pagefaults 0swaps 11.04user 0.66system 0:11.73elapsed 99%CPU (0avgtext+0avgdata 572maxresident)k 0inputs+0outputs (0major+168minor)pagefaults 0swaps bash$ for i in 1 2 3; do /usr/bin/time ./cut-post -b50-100,101-105,9999 big-lines > /dev/null; echo; done 8.65user 0.52system 0:09.20elapsed 99%CPU (0avgtext+0avgdata 560maxresident)k 0inputs+0outputs (0major+165minor)pagefaults 0swaps 8.59user 0.58system 0:09.20elapsed 99%CPU (0avgtext+0avgdata 556maxresident)k 0inputs+0outputs (0major+164minor)pagefaults 0swaps 8.53user 0.65system 0:09.21elapsed 99%CPU (0avgtext+0avgdata 560maxresident)k 0inputs+0outputs (0major+165minor)pagefaults 0swaps bash$ for i in 1 2 3; do /usr/bin/time ./cut-split -b50-100,101-105,9999 big-lines > /dev/null; echo; done 7.22user 0.66system 0:07.91elapsed 99%CPU (0avgtext+0avgdata 576maxresident)k 0inputs+0outputs (0major+169minor)pagefaults 0swaps 7.26user 0.61system 0:07.90elapsed 99%CPU (0avgtext+0avgdata 572maxresident)k 0inputs+0outputs (0major+168minor)pagefaults 0swaps 7.24user 0.64system 0:07.91elapsed 99%CPU (0avgtext+0avgdata 572maxresident)k 0inputs+0outputs (0major+168minor)pagefaults 0swaps ### fields bash$ yes "a:b:c:d:e" | dd of=fields ibs=10 count=1000000 iflag=fullblock bash$ for i in 1 2 3; do /usr/bin/time ./cut-pre -f2,3 -d: fields > /dev/null; echo; done 2.82user 0.06system 0:02.90elapsed 99%CPU (0avgtext+0avgdata 568maxresident)k 0inputs+0outputs (0major+167minor)pagefaults 0swaps 2.80user 0.05system 0:02.87elapsed 99%CPU (0avgtext+0avgdata 568maxresident)k 0inputs+0outputs (0major+167minor)pagefaults 0swaps 2.79user 0.05system 0:02.85elapsed 99%CPU (0avgtext+0avgdata 572maxresident)k 0inputs+0outputs (0major+168minor)pagefaults 0swaps bash$ for i in 1 2 3; do /usr/bin/time ./cut-post -f2,3 -d: fields > /dev/null; echo; done 2.58user 0.09system 0:02.68elapsed 99%CPU (0avgtext+0avgdata 556maxresident)k 0inputs+0outputs (0major+164minor)pagefaults 0swaps 2.63user 0.05system 0:02.69elapsed 99%CPU (0avgtext+0avgdata 560maxresident)k 0inputs+0outputs (0major+165minor)pagefaults 0swaps 2.61user 0.07system 0:02.69elapsed 99%CPU (0avgtext+0avgdata 556maxresident)k 0inputs+0outputs (0major+164minor)pagefaults 0swaps bash$ for i in 1 2 3; do /usr/bin/time ./cut-split -f2,3 -d: fields > /dev/null; echo; done 2.79user 0.05system 0:02.85elapsed 99%CPU (0avgtext+0avgdata 572maxresident)k 0inputs+0outputs (0major+168minor)pagefaults 0swaps 2.61user 0.06system 0:02.69elapsed 99%CPU (0avgtext+0avgdata 572maxresident)k 0inputs+0outputs (0major+168minor)pagefaults 0swaps 2.63user 0.09system 0:02.73elapsed 99%CPU (0avgtext+0avgdata 568maxresident)k 0inputs+0outputs (0major+167minor)pagefaults 0swaps ### --output-delimiter bash$ for i in 1 2 3; do /usr/bin/time ./cut-pre -f2,3 -d: --output-d=' ' fields > /dev/null; echo; done 2.82user 0.06system 0:02.90elapsed 99%CPU (0avgtext+0avgdata 572maxresident)k 0inputs+0outputs (0major+168minor)pagefaults 0swaps 2.81user 0.06system 0:02.88elapsed 99%CPU (0avgtext+0avgdata 572maxresident)k 0inputs+0outputs (0major+168minor)pagefaults 0swaps 2.80user 0.05system 0:02.86elapsed 99%CPU (0avgtext+0avgdata 572maxresident)k 0inputs+0outputs (0major+168minor)pagefaults 0swaps bash$ for i in 1 2 3; do /usr/bin/time ./cut-post -f2,3 -d: --output-d=' ' fields > /dev/null; echo; done 2.67user 0.05system 0:02.74elapsed 99%CPU (0avgtext+0avgdata 556maxresident)k 0inputs+0outputs (0major+164minor)pagefaults 0swaps 2.60user 0.09system 0:02.70elapsed 99%CPU (0avgtext+0avgdata 556maxresident)k 0inputs+0outputs (0major+164minor)pagefaults 0swaps 2.59user 0.08system 0:02.68elapsed 99%CPU (0avgtext+0avgdata 556maxresident)k 0inputs+0outputs (0major+164minor)pagefaults 0swaps bash$ for i in 1 2 3; do /usr/bin/time ./cut-split -f2,3 -d: --output-d=' ' fields > /dev/null; echo; done 2.75user 0.04system 0:02.80elapsed 99%CPU (0avgtext+0avgdata 568maxresident)k 0inputs+0outputs (0major+167minor)pagefaults 0swaps 2.63user 0.05system 0:02.69elapsed 99%CPU (0avgtext+0avgdata 572maxresident)k 0inputs+0outputs (0major+168minor)pagefaults 0swaps 2.61user 0.08system 0:02.70elapsed 99%CPU (0avgtext+0avgdata 576maxresident)k 0inputs+0outputs (0major+169minor)pagefaults 0swaps NOTES: cut-pre is the current implementation and was compiled from commit ec48beadf. cut-post was compiled after applying the above patch to commit ec48beadf. cut-split was compiled after applying the attached patch to commit ec48bead.
split-print_kth
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