Melkor-1/cread

Benchmarking Different Read Routines

Benchmarking Different Read Routines

Routines:

• readlines_mmap_memchr() - Memory-maps the file and replaces all newlines with null bytes whilst keeping track of the beginning of the lines.
• readlines_mmap_getline() - Memory-maps the file, opens a stream on the mapped file with fmemstream(), and uses readlines_getline() to read from it.
• readlines_getline() - Reads from a stream line by line with getline().
• readlines_fread() - Reads from stream in chunks (64K-256K depending on the size of size_t).
• readlines_read() - Reads from file descriptor in chunks (64K-256K depending on the size of size_t).

Environment:

gen_files was used to generate the files (a script borrowed from @CraigEstey on StackOverflow), and benchmark was used to benchmark each routine. Due to the large size, the /data directory that benchmark expect is not present in this repository. It should be trivial to replicate a similar (smaller or larger) data-set given gen_files.

The caches were flushed before each run with:

sync && echo 3 >| /proc/sys/vm/drop_caches

The benchmarks were conducted on a Linux virtual machine. As per neofetch's output:

CPU: Intel i5-8350U (2) @ 1.895GHz
Memory: 454MiB / 2933MiB

Building

To build the main test program, run:

make debug  # Or make release 

To run the main program with all options under valgrind:

make valgrind

To generate the benchmarks:

make benchmark

Use gen_files to generate the files in the data directory (that's what the benchmarking script expects).

The results are redirected to "log.txt". Root priveleges may be required for this.

To run the tests:

make test

Benchmarks:

Generated 9.5 GB of random text data, spanning 16 files. The L: is # of lines and W: is # of words.

F_01.txt: L:723938 W:715363 286M
    2.734618s fread
    3.214528s getline
    2.724019s mmap_getline
    2.793741s mmap_memchr
    2.382282s read

F_02.txt: L:1797557 W:1777578 1.6G
    15.836780s fread
    14.747851s getline
    14.493438s mmap_getline
    14.433059s mmap_memchr
    11.544710s read

F_03.txt: L:868508 W:858901 718M
    5.516691s fread
    6.325901s getline
    5.768159s mmap_getline
    6.288740s mmap_memchr
    5.345601s read

F_04.txt: L:1770447 W:1749818 748M
    5.940744s fread
    6.633095s getline
    6.086993s mmap_getline
    6.452443s mmap_memchr
    5.502765s read

F_05.txt: L:538590 W:532349 280M
    2.421899s fread
    2.652455s getline
    2.454733s mmap_getline
    2.602934s mmap_memchr
    2.267052s read

F_06.txt: L:1061222 W:1049762 1.9G
    18.299409s fread
    23.352706s getline
    16.143867s mmap_getline
    16.378157s mmap_memchr
    15.610494s read

F_07.txt: L:977623 W:966168 433M
    3.694574s fread
    4.209865s getline
    3.635462s mmap_getline
    4.034088s mmap_memchr
    3.563325s read

F_08.txt: L:1528488 W:1344242 7.3M
    0.465053s fread
    1.248155s getline
    0.895678s mmap_getline
    0.202998s mmap_memchr
    0.507976s read

F_09.txt: L:933222 W:920308 136M
    1.344580s fread
    1.685732s getline
    1.634934s mmap_getline
    1.433772s mmap_memchr
    1.316717s read

F_10.txt: L:1991643 W:1968250 810M
    6.613663s fread
    7.474445s getline
    6.827324s mmap_getline
    7.247532s mmap_memchr
    5.995010s read

F_11.txt: L:286725 W:283633 503M
    3.906051s fread
    4.549751s getline
    4.066533s mmap_getline
    4.473247s mmap_memchr
    3.707212s read

F_12.txt: L:469761 W:456504 13M
    0.211498s fread
    0.317302s getline
    0.302654s mmap_getline
    0.168478s mmap_memchr
    0.201805s read

F_13.txt: L:3239460 W:3195516 534M
    5.005339s fread
    5.715909s getline
    5.341514s mmap_getline
    5.111032s mmap_memchr
    4.526727s read

F_14.txt: L:3558066 W:3503292 352M
    3.539159s fread
    4.667701s getline
    4.273095s mmap_getline
    3.502702s mmap_memchr
    3.723208s read

F_15.txt: L:847341 W:837882 778M
    6.259525s fread
    6.900610s getline
    6.413894s mmap_getline
    6.945327s mmap_memchr
    5.730950s read

F_16.txt: L:1011765 W:1000220 581M
    4.905271s fread
    5.459073s getline
    4.972031s mmap_getline
    5.351933s mmap_memchr
    4.575030s read