MemGuard

MemGuard is a memory bandwidth reservation system for multi-core platforms that provides guaranteed memory bandwidth allocation to protect real-time and critical tasks from memory bandwidth contention.

For the basic version, see README-basic.md.

Features

• Read/write separate bandwidth reservation
  • Per-core LLC miss threshold assignment
  • Per-core LLC writeback threshold assignment
• Support for reserved bandwidth reclaiming
• Support for best-effort bandwidth sharing

ChangeLog

• Dec 2022: 5.15+ kernel support
• May 2022:
  • Read/write separate reservation (from RTAS'19)
  • Bandwidth reclaiming re-enabled (originally from RTAS'13)

Installation

Build

make

Load the module

insmod memguard.ko

Usage

Once the module is loaded, configure bandwidth thresholds and controls as follows:

Per-core LLC miss threshold assignment

Assign 500 MB/s for Cores 0,1,2,3:

echo mb 500 500 500 500 > /sys/kernel/debug/memguard/read_limit

Per-core LLC writeback threshold assignment

Assign 100 MB/s for Cores 0,1,2,3:

echo mb 100 100 100 100 > /sys/kernel/debug/memguard/write_limit

Reclaim control

Enable reclaiming of reserved bandwidth:

echo reclaim 1 > /sys/kernel/debug/memguard/control

Exclusive mode control

Strict reservation - Disable best-effort sharing and use only guaranteed bandwidth:

echo exclusive 0 > /sys/kernel/debug/memguard/control

Spare bandwidth sharing mode - Enable best-effort bandwidth sharing (see RTAS'13):

echo exclusive 2 > /sys/kernel/debug/memguard/control

Proportional share mode - Enable proportional best-effort bandwidth sharing (see TC'15):

echo exclusive 5 > /sys/kernel/debug/memguard/control