A demo of concurrency primitives in x64 assembly
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How to run:

  • Make sure you have a recent nasm; check that nasm -v reports 2.11 or newer.
$ git clone https://github.com/davidad/asm_concurrency.git
$ cd asm_concurrency
$ make
  • See results.
  • If you want to verify deterministic behavior, run make integrity_check.

You can also supply a command-line argument, which will be opened as a binary file.

$ make concurrency-noprint-x3 concurrency-noprint-x4
$ ./concurrency-noprint-x4 foo
$ ./concurrency-noprint-x3 bar
$ diff foo bar
$ # same results, yay!

The number after the x indicates how many processes will be forked by that executable. You can even run more than one instance of "concurrency" concurrently (shocking!).

$ make clean
$ make size=10000000 concurrency-noprint-x3
$ ./concurrency-noprint-x3 quux &            # this will take a little while
$ ./concurrency-noprint-x3 quux
$ ./concurrency-noprint-x3 quuux &
$ ./concurrency-noprint-x3 quuux &
$ ./concurrency-noprint-x3 quuux
$ diff quux quuux
$ # hoo-ah!

make options you can tweak (with their default values):

$ make size=1000000 "nprocs=1 2 3 4 5 6 7 8 9 10 11 12 13 14 15"
  • The output file will have size (size+1)*8. (This is due to keeping a bookkeeping quad-word in the file and assuming for simplicity that the file is an integer number of quad-words.)
  • nprocs specifies the set of executables to build and test (-x1, -x2, etc.). This should have just been a command-line argument, but eh, this way works.