MEMHOG(8)

✨ NAME ✨

okay so bestie, memhog is literally the tool that allocates memory with a policy attached, and it's for testing 🧪💖 It's giving stress test energy. memhog - Allocates memory with policy for testing.

🎀 SYNOPSIS 🎀

memhog [ -r<NUM> ] [ size kmg ] [ policy nodeset ] [ -f<filename> ]

💅 DESCRIPTION 💅

ngl this is the core of it. memhog mmaps a memory region for a given size and sets the numa policy (if you specify one) ✨ Then it keeps updating that memory region for however many iterations you ask for, using memset. Iconic.

Here are the flags you can slap on:

• -r<num> — repeat the memset NUM times 🔁
• -f<file> — open a file to use for mmap backing 📁
• -H — disable transparent hugepages, no thanks 🙅‍♀️
• -size — the allocation size in bytes. You can add a case-insensitive order suffix: G for gigabyte, M for megabyte, K for kilobyte 🌸

Now the numa policies, which are lowkey the best part 👑

Supported numa-policies:

• interleave — memory gets allocated round robin across the nodes 🦋 If memory can't be allocated on the current interleave node, it falls back to other nodes. You can specify multiple nodes here.
• membind — only allocate memory from these nodes. Allocation will fail if there isn't enough memory available on them, so no sneaking off to other nodes 🙅‍♀️ You can specify multiple nodes.
• preferred — preferably allocate memory on the node you pick, but if it can't fit there, fall back to other nodes 🌈 This one only takes a single node number, bestie.
• default — memory gets allocated on the local node, meaning whichever node the thread is running on 🧚

🍓 EXAMPLES 🍓

okay examples time, I'm obsessed with these 😭

Allocate a 1G region, mmap backed by the memhog.mmap file, membind to node 0, and repeat the test 6 times:

memhog -r6 1G --membind 0 -fmemhog.mmap

Allocate a 1G region, interleave across nodes 0, 1, 2, and 3, and repeat the test 4 times:

memhog -r4 1G --interleave 0-3

Allocate a 1G region with the (implicit) default policy, and repeat the test 8 times:

memhog -r8 1G

🫶 AUTHORS 🫶

Andi Kleen (ak@suse.de) — the legend herself 👑

🔥 LICENSE 🔥

GPL v2 💜

🦋 SEE ALSO 🦋

mmap(2), memset(3), numactl(8), numastat(8) ✨

okay bestie that's everything 🥹 memhog came from SuSE Labs, 2003,2004, and it's still giving 🎀 Stay iconic, stay testing 💖🧚