From f93aada69b0c8e147363ac317866d78a24eb9bfc Mon Sep 17 00:00:00 2001 From: Thomas Schwinge Date: Fri, 25 May 2018 16:15:38 +0200 Subject: Revert page removals of "Update gsoc ideas" ..., to avoid breaking existing links. Instead, mark as obsolete. This reverts parts of commit 4f15828febdea054993b2c21f62530c17ce3adea. --- community/gsoc/project_ideas/dtrace.mdwn | 67 ++++++++++++++++++++++++++++++++ 1 file changed, 67 insertions(+) create mode 100644 community/gsoc/project_ideas/dtrace.mdwn (limited to 'community/gsoc/project_ideas/dtrace.mdwn') diff --git a/community/gsoc/project_ideas/dtrace.mdwn b/community/gsoc/project_ideas/dtrace.mdwn new file mode 100644 index 00000000..f7aeb6e8 --- /dev/null +++ b/community/gsoc/project_ideas/dtrace.mdwn @@ -0,0 +1,67 @@ +[[!meta copyright="Copyright © 2008, 2009, 2011, 2018 Free Software Foundation, +Inc."]] + +[[!meta license="""[[!toggle id="license" text="GFDL 1.2+"]][[!toggleable +id="license" text="Permission is granted to copy, distribute and/or modify this +document under the terms of the GNU Free Documentation License, Version 1.2 or +any later version published by the Free Software Foundation; with no Invariant +Sections, no Front-Cover Texts, and no Back-Cover Texts. A copy of the license +is included in the section entitled [[GNU Free Documentation +License|/fdl]]."]]"""]] + +[[!meta title="Kernel Instrumentation"]] + +[[!tag open_issue_gnumach]] + +[[!template id=highlight text="""/!\ Obsolete /!\ + +--- + +This is no longer valid as a Google Summer of Code project."""]] + + +One of the main problems of the current Hurd implementation is very poor +[[open_issues/performance]]. While we have a bunch of ideas what could cause the performance +problems, these are mostly just guesses. Better understanding what really +causes bad performance is necessary to improve the situation. + +For that, we need tools for performance measurements. While all kinds of more +or less specific [[open_issues/profiling]] tools could be conceived, the most promising and +generic approach seems to be a framework for logging certain events in the +running system (both in the microkernel and in the Hurd servers). This would +allow checking how much time is spent in certain modules, how often certain +situations occur, how things interact, etc. It could also prove helpful in +debugging some issues that are otherwise hard to find because of complex +interactions. + +The most popular kernel instrumentation framework is Sun's dtrace, +originally written for Solaris, +but also adopted by some other systems. +However, the GPL-incompatible license means it can't be used in Linux, +and thus Linux developers created their own frameworks instead: +first [[SystemTap]], and now [[LTTng]]. + +In 2008, Andrei Barbu did initial work on kernel probes for the Hurd. +However, not all of his patches got merged, +because some turned out not to be fully functional. +Also, he didn't get around to work on userspace probes, +nor on a nice frontend for writing test scripts employing the probes. + +The goal of this project is to make the instrumentation framework +more usable and complete, +and to better integrate it in the Hurd. +For that, the student will have to work +on some real profiling and/or debugging tasks, +and fix any shortcomings he encounters in the framework. + +This is a pretty involved task. +Previous experience with low-level programming is a must; +and it also requires a good grasp on interactions in complex systems. + +To work on this project, +the student will have to get familiar with GNU Mach. +(The microkernel employed by the Hurd.) +Some understanding of other aspects of the Hurd will also be required, +depending on the exact nature of the profiling/debugging performed. + +Exercise: Use the existing probes to perform some simple measurement. -- cgit v1.2.3