[NetBSD Developer Wiki]
- view: text
- select for diffs
Sun Nov 6 01:59:12 2011 UTC
(5 years, 10 months ago) by jmmv
CVS tags: HEAD
Move existing project definitions from projects/gsoc_2011/ to
The goal for this reorganization is to remove any knowledge of the projects
classification from the file hierarchy: the classification goes into tags,
and projects indexes automatically list projects based on such tags.
Also, the current gsoc_2011 name was wrong anyway, because GSoC 2011 has
already concluded and projects would have had to move to a gsoc_2012 directory
Lastly, yes, "projects/project/*" is slightly redundant. But I want to keep
the project lists from the projects "database" clearly separated.
This is as proposed in www@.
title="Light weight precision user level time reading"
Design and implement a mechanism that allows for fast user level access to kernel time data structures for NetBSD. For certain types of small data structures the system call overhead is significant. This is especially true for frequently invoked system calls like [clock_gettime(2)](http://netbsd.gw.com/cgi-bin/man-cgi?clock_gettime+2+NetBSD-5.1+i386) and [gettimeofday(2)](http://netbsd.gw.com/cgi-bin/man-cgi?gettimeofday+2+NetBSD-5.1+i386). With the availability of user level readable high frequency counters it is possible to create fast implementations for precision time reading. Optimizing clock_gettime(2) and alike will reduce the strain from applications frequently calling these system calls and improves timing information quality for applications like NTP. The implementation would be based on a to be modified version of the timecounters implementation in NetBSD.
See also the [Paper on Timecounters by Poul-Henning Kamp](http://phk.freebsd.dk/pubs/timecounter.pdf).
CVSweb for NetBSD wikisrc <wikimaster@NetBSD.org> software: FreeBSD-CVSweb