snappy-start: Tool for process startup snapshots
snappy-start is a tool which takes a snapshot of a Linux program's process state after it has started up. It allows multiple instances of the program to be quickly launched from the snapshot.
This has two potential benefits:
Faster startup, if the program does a non-trivial amount of computation during startup.
Saving memory, because memory pages that the program writes to during startup will be shared between the instances.
First, build the tool by running
make.sh (which also runs some tests).
To create a snapshot:
./out/ptracer ./out/elf_loader PROG ARGS...
To run the snapshot:
The program will be snapshotted when it first calls an unhandled
syscall, such as
Currently, the snapshot data is written to hard-coded files
(containing register state and a list of memory mappings) and
(data to restore using
$ ./out/ptracer ./out/elf_loader /usr/bin/python tests/python_example.py $ ./out/restore Hello world, from restored Python process
The idea for this tool comes from Kenton Varda, who proposed using a
"record/replay" approach, using
ptrace() to monitor syscalls so that
they can later be replayed.