Browse Prior Art Database

User level writing to a pinned kernel buffer in an SMP system

IP.com Disclosure Number: IPCOM000013033D
Original Publication Date: 2000-Aug-01
Included in the Prior Art Database: 2003-Jun-12

Publishing Venue

IBM

Abstract

Disclosed is an algorithm that allows concurrent reading and writing of trace records to a single trace buffer without requiring a transition to supervisor mode in an SMP environment. There is a significant performance advantage to writing records without requiring supervisor mode. On NT*, the transition to kernel mode can take 1000-2000 cycles. This algorithm handles/avoids the following potential problems: (I) Multiple processors attempting to write data to the same area concurrently (II) Application record writes that are still in process when recording is completed (can occur with deadlocks and abended processes)