Analyzing and Improving CPU and Energy Efficiency of PM File Systems

Source code for our DIMES'23 paper: https://dl.acm.org/doi/10.1145/3609308.3625265

Efficient PM Copy

The source code of our efficient PM copy routines is in module/. To build it, you need a Linux 5.15 kernel with linux-5.15.diff applied.

We provide a patched kernel that includes NOVA support at https://github.com/KIT-OSGroup/linux/tree/ep-base Build, install and boot into that kernel as usual. Then, build our eff_pmem module and patched NOVA as follows:

make -C module
make -C nova

Insert eff_pmem.ko with appropriate parameters.

insmod module/eff_pmem.ko ep_max_memcpy_sem=2 worker_cpus=0,1 ep_dma_nchans=2 ep_mode=3

• ep_max_memcpy_sem: Number of parallel writers the semaphore allows
• worker_cpus: Set of CPUs for the workqueue worker threads
• ep_dma_nchans: Number of I/OAT DMA channels
• ep_mode: Which variant to use. See EP_MODE_* constants in module/eff_pmem.c. 3: normal copy, 4: Semaphore, 2: Workqueue, 1: DMA

You can also change ep_mode later by writing to /sys/module/eff_pmem/parameters/ep_mode.

Finally, load and use NOVA as usual (insmod nova/nova.ko).