pre fetching releases reduced total run time 30 60

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: I/O waits in 85% of test cases • reduced additional OS overhead by avoiding page faults Results Results (cont.) Pre-fetching + releases • Reduced total run time 30% - 60% Interactive apps could remain in memory Out Out-of-core app performance Why does release help out-of-core apps? Impact interactive Impact on interactive apps Conclusion Conclusion Too much data, not enough memory Application can help out the OS Compiler inserts data pre-fetch and release Adaptive run-time system Reduces thrashing, improves performance, plays nicely with other other apps on the system Midterm Midterm Review Closed book, 1.5 hour – covers material from day 1 through today today (Memory Hogs) threads, processes, scheduling, synchronization, deadlock, and and memory management, including research papers Sample exam from older class – note: this is just an idea of the length and depth of questions Midterm Midterm Mixture of short answer (book, HW) questions (~ 40%) few sentence answers Longer analysis or “to do” questions (~ 60%) I will ask you to implement/solve some kind of synchronization synchronization problem I will ask you about segmentation Midterm Midterm Stress material covered in class Sample questions: What is the difference between logical and physical concurrency? What is test-and-set-lock? Give an example showing what it is used for. Explain why it achieves atomic execution on a multiprocessor in which threads can run on separate CPUs (and still share variables), while interrupts do not. Midterm Midterm Multi-threaded Synchronization. We wish to synchronize a single pair of threads (a server and a client) that each run continuously. The server thread waits and blocks for a request from the client. The client issues a request by placing the request data in a shared variable (x) and then blocks waiting for a return value (Ans) stored by the server thread. thread. (a) Show a sketch of the client and server code using semaphores (b) Show a sketch of the client and server code using condition variables CSci CSci 5103 Operating Systems I/O – Chapter 5 Coverage Coverage Lots of nitty gritty hardware issues We will focus on the most interesting aspects of I/O disks – RAID, scheduling stable...
View Full Document

This document was uploaded on 04/02/2014.

Ask a homework question - tutors are online