From fca59bea770346cf1c1f9b0e00cb48a61b44a8f3 Mon Sep 17 00:00:00 2001 From: Harald Welte Date: Sun, 25 Oct 2015 21:00:20 +0100 Subject: import of old now defunct presentation slides svn repo --- .../OLS2005/denijs/denijs-abstract.tex | 39 ++++++++++++++++++++++ 1 file changed, 39 insertions(+) create mode 100644 2005/flow-accounting-ols2005/OLS2005/denijs/denijs-abstract.tex (limited to '2005/flow-accounting-ols2005/OLS2005/denijs/denijs-abstract.tex') diff --git a/2005/flow-accounting-ols2005/OLS2005/denijs/denijs-abstract.tex b/2005/flow-accounting-ols2005/OLS2005/denijs/denijs-abstract.tex new file mode 100644 index 0000000..f821300 --- /dev/null +++ b/2005/flow-accounting-ols2005/OLS2005/denijs/denijs-abstract.tex @@ -0,0 +1,39 @@ +% [1]>linuxsymposium July 20-23rd, 2005, Ottawa, Canada + +% Registration Active Block I/O Scheduling System (ABISS) +% +% [2]Register/Submit Giel de Nijs (giel.de.nijs@philips.com) + +The Active Block I/O Scheduling System (ABISS) is an +extension of the hard-disk storage subsystem of Linux. +It is designed to provide guaranteed reading and +writing bitrates to applications, with minimal overhead +and low latency. The core element of ABISS is a +scheduler that performs intelligent read-ahead or +write-back, based on the access profile the application +has previously requested. An adaptation of existing +work on incorporating support for priority requests +into the elevator (``IO scheduler'') is part of our +implementation, and enables ABISS to ensure that +real-time requests are served in a timely manner. +Besides the extension to the storage subsystem, we have +implemented experimental support for delayed allocation +in the FAT file system, to be effectively able to +provide the guaranteed writing bitrates. We are working +on combining this with disk space reservations, which +are also part of on-going development on ext3. +Applications use the regular POSIX API, and control the +ABISS extensions either directly through ioctls, or a +library offering simple wrapper functions. ABISS +contains by a user-space demon that oversees resource +allocation and handles admission control. Also some +minor modifications were made to file system drivers. +ABISS currently supports FAT, VFAT, ext2, and ext3. In +a set of experimental runs with real-life data rates on +a deliberately not very powerful test system reflecting +a typical embedded device, we have measured that all +read and write operations completed within 6 ms, while +a background load of eight concurrent greedy readers or +writers, served in a best-effort way, experienced +delays worse by a factor of more than 4000. + -- cgit v1.2.3