MNEMOSYNE

Mnemosyne: Lightweight Persistent Memory

Haris Volos, Andres Jaan Tack and Michael M. Swift. ASPLOS 2012

Mnemosyne provides a simple interface for programming with persistent memory. Mnemosyne addresses two challenges: how to create and manage such memory, and how to ensure consistency in the presence of failures. Without additional mechanisms, a system failure may leave data structures in SCM in an invalid state, crashing the program the next time it starts.

In Mnemosyne, programmers declare global persistent data with the keyword persistent or allocate it dynamically. Mnemosyne provides primitives for directly modifying persistent variables and supports consistent updates through a lightweight transaction mechanism. Compared to past work on disk-based persistent memory, Mnemosyne is much lighter weight, as it can store data items as small as a word rather than a virtual memory page. In tests emulating the performance characteristics of forthcoming SCMs, we find that Mnemosyne provides a 20--280 percent performance increase for small data sizes over alternative persistence strategies, such as Berkeley DB or Boost serialization that are designed for disks.

DEPENDENCIES:

SCons: A software construction tool
Preferable, GCC 6.2.1 and above
libconfig

	Fedora : $ dnf install libconfig-devel.x86_64 libconfig.x86_64
	Ubuntu : $ apt-get install libconfig-dev libconfig9

gelf

	Fedora : $ dnf install elfutils-libelf-devel.x86_64 elfutils-libelf.x86_64
	Ubuntu : $ apt-get install libelf-dev elfutils

libevent (For memcached)

	Fedora : $ dnf install libevent-devel.x86_64 
	Ubuntu : $ apt-get install libevent-dev

Boost library

 	Ubuntu : sudo apt-get install libboost-all-dev

/dev/shm or mount point backed by persistent memory
- The heap will be placed in segments_dir defined in mnemosyne.ini
- Please ensure you have at least 1.00 GB of space for the heap.

TO BUILD :

$ cd usermode
$ scons [--build-stats] [--config-ftrace] [--verbose]
 
* scons -h <For more options>

TO BUILD AND RUN A SIMPLE EXAMPLE:

Simple example
- Read and modify value of persistent flag across executions
- Test pmalloc - persistent memory allocator
- Test concurrent reader and writer

$ cd usermode
$ scons --build-example=simple
$ ./build/examples/simple/simple 
persistent flag: 0 --> 1
&persistent flag = 0x100020038000

starting pmalloc bench
persistent ptr =0x100ba0035fe0, sz=32
persistent ptr & cl_mask = 0x100ba0035fc0
(WRITER) persistent ptr =0x100ba0035fe0, sz=32
(READER) persistent ptr =0x100ba0035fe0, sz=32

$ ./build/examples/simple/simple 
persistent flag: 1 --> 0
&persistent flag = 0x100020038000

starting pmalloc bench
persistent ptr =0x100ba0035fc0, sz=32
persistent ptr & cl_mask = 0x100ba0035fc0
(WRITER) persistent ptr =0x100ba0035fc0, sz=32
(READER) persistent ptr =0x100ba0035fc0, sz=32

TO BUILD AND RUN A COMPLEX BENCHMARK:

TO BUILD VACATION:

$ cd usermode
$ scons --build-bench=stamp-kozy [--verbose]

TO BUILD MEMCACHED:

$ scons --build-bench=memcached  [--verbose]
* Check run_*.sh scripts to learn more on how to run memcached.

TO INITIALIZE VACATION:

$ cd usermode
$ export LD_LIBRARY_PATH=`pwd`/library:$LD_LIBRARY_PATH
$ ./build/bench/stamp-kozy/vacation/vacation -c0 -n1 -r65536 -q100

TO RUN VACATION:

$ cd usermode
$ export LD_LIBRARY_PATH=`pwd`/library:$LD_LIBRARY_PATH
$ ./build/bench/stamp-kozy/vacation/vacation -t1000 -c2 -n10 -r65536 -q90 -u100

    Table Index         = RBTREE
    Transactions        = 1000
    Clients             = 2
    Transactions/client = 500
    Queries/transaction = 10
    Relations           = 65536
    Query percent       = 90
    Query range         = 58982
    Percent user        = 100
    Enable trace        = 0
Initializing manager... 

***************************************************

Re-using tables from previous incarnation...

Persistent table pointers.

Car Table      = 0x100ba0035ff0
Room Table     = 0x100ba0035fe0
Flight Table   = 0x100ba0035fd0
Customer Table = 0x100ba0035fc0

***************************************************
Initializing clients... done.

Running clients...

Starting thread 9201
Thread-0 finished 500 queries
Starting thread 9203
Thread-1 finished 500 queries
done.Time = 0.127621
Deallocating memory... done.

DOCUMENTATION:

For further information please refer to the Doxygen generated documentation. Running doxygen will create documentation under mnemosyne/doc/html

$ cd ./usermode/.. $ doxygen

AUTHORS:

Haris Volos hvolos@cs.wisc.edu
Andres Jaan Tack tack@cs.wisc.edu
Sanketh Nalli nalli@wisc.edu

LICENSE:

GPL-V2 See license file under each module

qtcwt / mnemosyne-gcc