vmcache

Code repository for SIGMOD'23 paper Virtual-Memory Assisted Buffer Management. This is the buffer manager implementation. exmap is in a separate repository.

Environment Variables

• BLOCK: storage block device (e.g. /dev/nvme0n1 or /dev/md0); default=/tmp/bm
• VIRTGB: virtual memory allocation in GB (e.g., 1024), should be at least device size; default=16
• PHYSGB: physical memory allocation in GB = buffer pool size, should be less than available RAM; default=4
• EXMAP: if non-zero, use exmap interface, requires exmap kernel module; default=0
• BATCH: batch size for eviction in pages; default=64
• RUNFOR: benchmark run duration in seconds; default=30
• RNDREAD: if non-zero, run random read benchmark, otherwise TPC-C; default=0
• THREADS: number of threads; default=1
• DATASIZE: number of warehouses for TPC-C, number of tuples for random read benchmark; default=10

Example Command Lines

• TPC-C, 4 threads, 2 warehouses: BLOCK=/dev/nvme0n1 THREADS=4 DATASIZE=2 ./vmcache
• random read, 10 threads, 1 million tuples: BLOCK=/dev/md0 THREADS=10 DATASIZE=1e6 ./vmcache

Dependencies and Configuration

We need the libaoi library. On Ubuntu: sudo apt install libaio-dev. You will probably also need to set vm.overcommit_memory = 1 in /etc/sysctl.conf. Otherwise larger values of VIRTGB will not work.

If you want to use EXMAP, you need the exmap kernel module.

Citation

Please cite the paper as follows:

@inproceedings{vmcache,
  author    = {Viktor Leis and Adnan Alhomssi and Tobias Ziegler and Yannick Loeck and Christian Dietrich},
  title     = {Virtual-Memory Assisted Buffer Management},
  booktitle = {SIGMOD},
  year      = {2023},
}

Low-Hanging Fruit (TODO)

• use C++ wait/notify to handle lock contention instead of spinning
• implement free space management for storage