Muli Ben-Yehuda's journal

An interesting project that was mentioned today in the Storage and
Systems dept. seminar is ABISS
– Active Block I/O Scheduling Subsystem.

The Active Block I/O Scheduling System (ABISS) is an extension of the
hard-disk storage subsystem of Linux, whose main purpose is to
provide a guaranteed reading and writing bit rate to
applications. Apart from these guaranteed real-time (RT) streams, we
also included multiple priorities for best-effort (BE) disk traffic.

The system consists of a framework that is added to the kernel,
including an elevator implementing multiple priorities, with a policy
and coordination unit implemented in user space. This approach ensures
separation between the kernel infrastructure (the framework) and the
policies (e.g. admission control) in user space.

The ABISS extensions are controlled through ioctls applied to files
accessed through the regular POSIX API. A small library with wrapper
functions shaped after stdio (abiss_fopen(), abiss_fread(),
abiss_fwrite(), etc.) is available for applications preferring a
higher-level API.

This project is conducted by Philips Research, Eindhoven.

My manager Alain Azagury mentioned this work from the Almaden lab on Thursday: Adaptive Replacement Cache, which uses a combination of LRU and Most Frequently Used eviction algorithms to get excellent cache utilization. Sounds very interesting; pushed to the top of my to-read papers list.

brad has very interesting slides on livejournal’s backend from his Lisa talk here.

Having just booked a week in Paris before Christmas for Orna and me, the world suddenly seems a much better place.