Flexible Memory Allocation Tool for multi-tiered memory systems

• What is the Flexible Memory Allocation Tool?
• Requirements
• Status
• Building the tool
• Using the tool
• Environment variables
• Copyrights

The Flexible Memory Allocation Tool is an interposition library that allocates dynamic-memory objects into designated memory systems on a multi-tiered memory system based on a user-given configuration without having to alter the application binary. This tool takes two inputs:

1. Definition of the memory tiers and their respective allocators (e.g. various flavors of memkind)
2. Code-locations of dynamic allocations that are forwarded to specific allocators

• Linux OS
• C++ compiler (g++ 4.8 will do)
• Optionally:
  • binutils - to enable human-readable call-stack matching
  • Memkind - to enable promoting memory allocations to Memkind handled memory (e.g. Intel Optane Persistent Memory or HBM)
  • PMDK - takes advantage of fast pmem_copy routines
  • PAPI - collect some performance metrics

Create a build directory

mkdir build

Go inside that build directory

cd build

Issue the configure

../configure --prefix=INSTALL_DIR --with-memkind=MEMKIND_DIR --with-pmdk=PMDK_DIR

and adapt the respective DIRectories to fit your installation. Ensure that you have permissions to install in INSTALL_DIR.

Compile and install

make && make install

To use the tool, you need to prepare two configuration files.

1. Memory definitions: This file refers to a list of the available memory tiers/subsystems in the machine. For instance, a base configuration for a DRAM-only system (handled by regular posix calls) and with a limit of 4 GB per process would look like:

$ cat base-memory-configuration
# Memory configuration for allocator posix
Size 4096 MBytes

The following configuration file is for a heterogeneous memory system composed by Intel Optane Persistent Memory (handled by memkind) and DRAM (limited to 1GB per process). In this scenario, the memkind/pmem allocator specifies one mount point per socket.

# Memory configuration for allocator posix
Size 1024 Mbytes
# Memory configuration for allocator memkind/pmem
@ /mnt/pmem0 @ /mnt/pmem1

2. Memory locations: This file refers to a list of pairs composed by call-stacks and the memory tier where the data object shall be allocated. The call-stacks are defined by a sequence of code locations identified by pairs of file:line number. For instance, the following allocations file would forward allocations found in lines 252, 253, and 254 in stream-manymallocs.c and invoked from line 342 on libc-start to the posix memory allocator.

$ cat stream-manymallocs-locations
# Memory configuration with size 0 bytes on allocator posix
# This is an example. The format is, one line per call-stack, on each line the complete call-stack
# e.g. file1.c:line1 > file2.c:line2 > file3.c:line3 ... > fileN.c:lineN
stream-manymallocs.c:252 > libc-start.c:342 @ posix
stream-manymallocs.c:253 > libc-start.c:342 @ posix
stream-manymallocs.c:254 > libc-start.c:342 @ posix

Once you have the configuration files, issue:

$INSTALL_DIR/bin/flexmalloc.sh memory-definitions.cfg memory-locations.cfg <binary & params>

where binary and params refers to the binary to be executed and the parameters being passed to that execution.

© 2022 Harald Servat, Intel Corporation

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* Other names and brands may be claimed as the property of others.

We welcome anyone interested in using, developing or contributing in Flexible Memory Tool!

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