diff options
Diffstat (limited to 'community/gsoc')
| -rw-r--r-- | community/gsoc/2010.mdwn | 35 | ||||
| -rw-r--r-- | community/gsoc/project_ideas.mdwn | 16 | ||||
| -rw-r--r-- | community/gsoc/project_ideas/disk_io_performance.mdwn | 50 | ||||
| -rw-r--r-- | community/gsoc/project_ideas/driver_glue_code.mdwn | 84 | ||||
| -rw-r--r-- | community/gsoc/project_ideas/dtrace.mdwn | 62 | ||||
| -rw-r--r-- | community/gsoc/project_ideas/libdiskfs_locking.mdwn | 45 | ||||
| -rw-r--r-- | community/gsoc/project_ideas/procfs.mdwn | 51 | ||||
| -rw-r--r-- | community/gsoc/project_ideas/secure_chroot.mdwn | 2 | ||||
| -rw-r--r-- | community/gsoc/project_ideas/testing_framework.mdwn | 55 | ||||
| -rw-r--r-- | community/gsoc/project_ideas/testing_framework/discussion.mdwn | 270 | ||||
| -rw-r--r-- | community/gsoc/project_ideas/testsuites.mdwn | 18 | ||||
| -rw-r--r-- | community/gsoc/project_ideas/valgrind.mdwn | 83 |
12 files changed, 730 insertions, 41 deletions
diff --git a/community/gsoc/2010.mdwn b/community/gsoc/2010.mdwn new file mode 100644 index 00000000..4388636b --- /dev/null +++ b/community/gsoc/2010.mdwn @@ -0,0 +1,35 @@ +[[!meta copyright="Copyright © 2008, 2009, 2010, 2011 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="Google Summer of Code 2010"]] + +In 2010 we have again been participating in the Google Summer of Code +under the GNU umbrella, with three slots: + + * *[[Jeremie Koenig|jkoenig]]*, mentored by *[[Samuel + Thibault|samuelthibault]]*, has been working on adapting the Debian Installer to + [produce working Debian GNU/Hurd installation + images](http://socghop.appspot.com/gsoc/student_project/show/google/gsoc2010/debian/t127230758239) + so we can easily offer up to date disc-sets. + ([Details](http://wiki.debian.org/SummerOfCode2010/HurdDebianInstaller/JeremieKoenig).) + + * *[[Emilio Pozuelo Monfort|pochu]]*, mentored by *Carl Fredrik Hammar* (who + was a GSoC student in [[2007]]), has been working on a task that may be perceived as + less exciting from the outside, but yet is extremely valuable: [fixing + compatibility problems exposed by projects' + testsuites](http://socghop.appspot.com/gsoc/student_project/show/google/gsoc2010/gnuproject/t127230759396). + ([[Details|community/gsoc/project_ideas/testsuites]].) + + * *[[Karim Allah Ahmed|kam]]*, mentored by *Sergio López*, has been working on + [tuning the VM Subsystem in + GNU/Hurd](http://socghop.appspot.com/gsoc/student_project/show/google/gsoc2010/gnuproject/t127230759587) + to bring the virtual memory management in Hurd/Mach up to date. + ([[Details|community/gsoc/project_ideas/vm_tuning]].) diff --git a/community/gsoc/project_ideas.mdwn b/community/gsoc/project_ideas.mdwn index 649e05c1..4f028e4f 100644 --- a/community/gsoc/project_ideas.mdwn +++ b/community/gsoc/project_ideas.mdwn @@ -1,4 +1,4 @@ -[[!meta copyright="Copyright © 2008, 2009, 2010 Free Software Foundation, +[[!meta copyright="Copyright © 2008, 2009, 2010, 2011 Free Software Foundation, Inc."]] [[!meta license="""[[!toggle id="license" text="GFDL 1.2+"]][[!toggleable @@ -76,16 +76,20 @@ will assist you as well as we can. See also the list of [Hurd-related X.org project ideas](http://wiki.x.org/wiki/Hurd_Porting). +<!-- These X.org tasks are also listed on +<http://xorg.freedesktop.org/wiki/SummerOfCodeIdeas>, which is the page used by +X.org for referring to their GSoC projects. Probabaly we should get rid of one +of these pages (to avoid duplication). --> + [[!inline pages="community/gsoc/project_ideas/language_bindings" show=0 feeds=no actions=yes]] [[!inline pages="community/gsoc/project_ideas/virtualization" show=0 feeds=no actions=yes]] [[!inline pages="community/gsoc/project_ideas/file_locking" show=0 feeds=no actions=yes]] [[!inline pages="community/gsoc/project_ideas/server_overriding" show=0 feeds=no actions=yes]] [[!inline pages="community/gsoc/project_ideas/tcp_ip_stack" show=0 feeds=no actions=yes]] [[!inline pages="community/gsoc/project_ideas/nfs" show=0 feeds=no actions=yes]] -[[!inline pages="open_issues/locking" show=0 feeds=no actions=yes]] [[!inline pages="community/gsoc/project_ideas/pthreads" show=0 feeds=no actions=yes]] [[!inline pages="community/gsoc/project_ideas/sound" show=0 feeds=no actions=yes]] -[[!inline pages="open_issues/performance/io_system" show=0 feeds=no actions=yes]] +[[!inline pages="community/gsoc/project_ideas/disk_io_performance" show=0 feeds=no actions=yes]] [[!inline pages="community/gsoc/project_ideas/vm_tuning" show=0 feeds=no actions=yes]] [[!inline pages="community/gsoc/project_ideas/mtab" show=0 feeds=no actions=yes]] [[!inline pages="community/gsoc/project_ideas/gnumach_cleanup" show=0 feeds=no actions=yes]] @@ -95,7 +99,6 @@ See also the list of [Hurd-related X.org project ideas](http://wiki.x.org/wiki/H [[!inline pages="community/gsoc/project_ideas/lexical_dot-dot" show=0 feeds=no actions=yes]] [[!inline pages="community/gsoc/project_ideas/secure_chroot" show=0 feeds=no actions=yes]] [[!inline pages="community/gsoc/project_ideas/package_manager" show=0 feeds=no actions=yes]] -[[!inline pages="community/gsoc/project_ideas/debian_installer" show=0 feeds=no actions=yes]] [[!inline pages="community/gsoc/project_ideas/download_backends" show=0 feeds=no actions=yes]] [[!inline pages="community/gsoc/project_ideas/libgtop" show=0 feeds=no actions=yes]] [[!inline pages="community/gsoc/project_ideas/maxpath" show=0 feeds=no actions=yes]] @@ -104,6 +107,9 @@ See also the list of [Hurd-related X.org project ideas](http://wiki.x.org/wiki/H [[!inline pages="community/gsoc/project_ideas/cdparanoia" show=0 feeds=no actions=yes]] [[!inline pages="community/gsoc/project_ideas/perl_python" show=0 feeds=no actions=yes]] [[!inline pages="community/gsoc/project_ideas/testsuites" show=0 feeds=no actions=yes]] +[[!inline pages="community/gsoc/project_ideas/testing_framework" show=0 feeds=no actions=yes]] [[!inline pages="community/gsoc/project_ideas/libcap" show=0 feeds=no actions=yes]] [[!inline pages="community/gsoc/project_ideas/xattr" show=0 feeds=no actions=yes]] -[[!inline pages="open_issues/valgrind" show=0 feeds=no actions=yes]] +[[!inline pages="community/gsoc/project_ideas/valgrind" show=0 feeds=no actions=yes]] +[[!inline pages="community/gsoc/project_ideas/driver_glue_code" show=0 feeds=no actions=yes]] +[[!inline pages="community/gsoc/project_ideas/dtrace" show=0 feeds=no actions=yes]] diff --git a/community/gsoc/project_ideas/disk_io_performance.mdwn b/community/gsoc/project_ideas/disk_io_performance.mdwn new file mode 100644 index 00000000..ae634709 --- /dev/null +++ b/community/gsoc/project_ideas/disk_io_performance.mdwn @@ -0,0 +1,50 @@ +[[!meta copyright="Copyright © 2008, 2009, 2010, 2011 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="Disk I/O Performance Tuning"]] + +[[!tag open_issue_hurd]] + +The most obvious reason for the Hurd feeling slow compared to mainstream +systems like GNU/Linux, is a low I/O system performance, in particular very +slow hard disk access. + +The reason for this slowness is lack and/or bad implementation of common +optimization techniques, like scheduling reads and writes to minimize head +movement; effective block caching; effective reads/writes to partial blocks; +[[reading/writing multiple blocks at once|open_issues/performance/io_system/clustered_page_faults]]; and +[[open_issues/performance/io_system/read-ahead]]. The +[[ext2_filesystem_server|hurd/translator/ext2fs]] might also need some +optimizations at a higher logical level. + +The goal of this project is to analyze the current situation, and implement/fix +various optimizations, to achieve significantly better disk performance. It +requires understanding the data flow through the various layers involved in +disk access on the Hurd ([[filesystem|hurd/virtual_file_system]], +[[pager|hurd/libpager]], driver), and general experience with +optimizing complex systems. That said, the killing feature we are definitely +missing is the [[open_issues/performance/io_system/read-ahead]], and even a very simple implementation would bring +very big performance speedups. + +Here are some real testcases: + + * [[open_issues/performance/io_system/binutils_ld_64ksec]]; + + * running the Git testsuite which is mostly I/O bound; + + * use [[TopGit]] on a non-toy repository. + + +Possible mentors: Samuel Thibault (youpi) + +Exercise: Look through all the code involved in disk I/O, and try something +easy to improve. It's quite likely though that you will find nothing obvious -- +in this case, please contact us about a different exercise task. diff --git a/community/gsoc/project_ideas/driver_glue_code.mdwn b/community/gsoc/project_ideas/driver_glue_code.mdwn index 9c063e9f..65ea4f0f 100644 --- a/community/gsoc/project_ideas/driver_glue_code.mdwn +++ b/community/gsoc/project_ideas/driver_glue_code.mdwn @@ -1,5 +1,4 @@ -[[!meta copyright="Copyright © 2008, 2009, 2010 Free Software Foundation, -Inc."]] +[[!meta copyright="Copyright © 2008, 2009, 2010, 2011 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 @@ -9,41 +8,64 @@ 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="New Driver Glue Code"]] +[[!meta title="New Driver Framework"]] -Although a driver framework in user space would be desirable, presently the Hurd -uses kernel drivers in the microkernel, -[[GNU_Mach|microkernel/mach/gnumach]]. (And changing this would be far beyond a -GSoC project...) - -The problem is that the drivers in GNU Mach are presently old Linux drivers -(mostly from 2.0.x) accessed through a glue code layer. This is not an ideal -solution, but works quite OK, except that the drivers are very old. The goal of -this project is to redo the glue code, so we can use drivers from current Linux -versions, or from one of the free BSD variants. - -While it would be certainly possible to create custom glue code again, a more -sustainable and probably also easier approach is to use -[[DDE]] instead -- it already -does the hard work of providing an environment where the foreign drivers can -run, and has the additional advantage of being externally maintained. - -This is a doable, but pretty involved project. Previous experience with driver -programming probably is a must. (No Hurd-specific knowledge is required, -though.) +The Hurd presently uses hardware drivers +implemented in the microkernel, [[GNU_Mach|microkernel/mach/gnumach]]. +These drivers are old Linux drivers (mostly from 2.0.x) +accessed through a glue code layer. +This is not an ideal solution, but works quite OK, +except that the drivers are extremely old by now. +Thus we need a new framework, +so we can use drivers from current Linux versions instead, +or perhaps from one of the free BSD variants. This is [[!GNU_Savannah_task 5488]]. [[open issues/user-space device drivers]]. [[open issues/device drivers and io systems]]. +The most promising approach for getting newer drivers seems to be [[DDE]]: +it already does the hard work of providing an environment +where the foreign drivers can run, +and offers the additional benefit of being externally maintained. +DDE also offers the necessary facilities +for running all drivers in separate userspace processes, +which is more desirable than drivers running in the microkernel. -Possible mentors: Samuel Thibault (youpi) +[[Zheng Da|zhengda]] has already done considerable work on this. +The basic framework for using DDE in the Hurd is present, +and network card drivers are already working very well. +However, this work isn't fully integrated in the Hurd yet. +The additional kernel interfaces that were created for this +are still prototypes, and will need to be reworked. +Also, there is no build system for automatically compiling +all Linux network card drivers in one go. + +Other types of drivers are missing so far. +Support for IDE drivers has been partially implemented, +but isn't fully working yet. +To fully replace the old in-kernel drivers, +further infrastructure will be necessary +to make userspace disk drivers usable for the root filesystem. -Exercise: Take a driver for some newer piece of hardware (e.g. Intel e1000 -ethernet) from a recent system, and try to port it to run in the existing -driver framework in GNU Mach. Completing the port might be too involved for the -exercise; but it's pretty likely that you will find something else to improve -in the glue code while working on this... +Some other subsystems are missing or incomplete in DDE itself, +and will require additional work that is not specific to the Hurd implementation. + +The goal of this task is to fix at least one of the mentioned major shortcomings: +rework the kernel interfaces; +provide a streamlined build system for the drivers; +finish IDE support; +or implement support for some other subsystem. +<!-- should probably provide separate task descriptions for each... --> + +This is a doable, but pretty involved project. +Previous experience with driver programming probably is a must. +To be able to work on the framework, +the student will also have to get a good understanding of certain aspects of Hurd, +such as memory management for example. + +Possible mentors: Samuel Thibault (youpi) -*Status*: [[Zheng Da|zhengda]] is working on DDE, and has mostly completed the -initial port. +Exercise: Get one of the not yet integrated Linux network card drivers to work. +(Note: This should be straightforward, +once you have the framework properly built and set up...) diff --git a/community/gsoc/project_ideas/dtrace.mdwn b/community/gsoc/project_ideas/dtrace.mdwn new file mode 100644 index 00000000..6261c03e --- /dev/null +++ b/community/gsoc/project_ideas/dtrace.mdwn @@ -0,0 +1,62 @@ +[[!meta copyright="Copyright © 2008, 2009, 2011 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]] + +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. + +Possible mentors: Samuel Thibault (youpi) + +Exercise: Use the existing probes to perform some simple measurement. diff --git a/community/gsoc/project_ideas/libdiskfs_locking.mdwn b/community/gsoc/project_ideas/libdiskfs_locking.mdwn new file mode 100644 index 00000000..faac8bd9 --- /dev/null +++ b/community/gsoc/project_ideas/libdiskfs_locking.mdwn @@ -0,0 +1,45 @@ +[[!meta copyright="Copyright © 2008, 2009, 2010, 2011 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="Fix libdiskfs Locking Issues"]] + +[[!tag open_issue_hurd]] + +Nowadays the most often encountered cause of Hurd crashes seems to be lockups +in the [[hurd/translator/ext2fs]] server. One of these could be traced +recently, and turned out to be a lock inside [[hurd/libdiskfs]] that was taken +and not released in some cases. There is reason to believe that there are more +faulty paths causing these lockups. + +The task is systematically checking the [[hurd/libdiskfs]] code for this kind of locking +issues. To achieve this, some kind of test harness has to be implemented: For +example instrumenting the code to check locking correctness constantly at +runtime. Or implementing a [[open_issues/unit_testing]] framework that explicitly checks +locking in various code paths. (The latter could serve as a template for +implementing unit tests in other parts of the Hurd codebase...) + +(A [[systematic code review|open_issues/security]] would probably suffice to find the +existing locking +issues; but it wouldn't document the work in terms of actual code produced, and +thus it's not suitable for a GSoC project...) + +This task requires experience with debugging locking issues in +[[multithreaded|open_issues/multithreading]] applications. + +Tools have been written for automated [[open_issues/code_analysis]]; these can help to +locate and fix such errors. + +Possible mentors: Samuel Thibault (youpi) + +Exercise: If you could actually track down and fix one of the existing locking +errors before the end of the application process, that would be excellent. This +might be rather tough though, so probably you need to talk to us about an +alternative exercise task... diff --git a/community/gsoc/project_ideas/procfs.mdwn b/community/gsoc/project_ideas/procfs.mdwn new file mode 100644 index 00000000..b4d1dc5f --- /dev/null +++ b/community/gsoc/project_ideas/procfs.mdwn @@ -0,0 +1,51 @@ +[[!meta copyright="Copyright © 2008, 2009, 2011 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="procfs"]] + +Although there is no standard (POSIX or other) for the layout of the `/proc` +pseudo-filesystem, it turned out a very useful facility in GNU/Linux and other +systems, and many tools concerned with process management use it. (`ps`, `top`, +`htop`, `gtop`, `killall`, `pkill`, ...) + +Instead of porting all these tools to use [[hurd/libps]] (Hurd's official method for +accessing process information), they could be made to run out of the box, by +implementing a Linux-compatible `/proc` filesystem for the Hurd. + +The goal is to implement all `/proc` functionality needed for the various process +management tools to work. (On Linux, the `/proc` filesystem is used also for +debugging purposes; but this is highly system-specific anyways, so there is +probably no point in trying to duplicate this functionality as well...) + +The [[existing_partially_working_procfs_implementation|hurd/translator/procfs]] +can serve as a starting point, but needs to be largely rewritten. (It should +use [[hurd/libnetfs]] rather than [[hurd/libtrivfs]]; the data format needs to +change to be more Linux-compatible; and it needs adaptation to newer system +interfaces.) + +This project requires learning [[hurd/translator]] programming, and +understanding some of the internals of process management in the Hurd. It +should not be too hard coding-wise; and the task is very nicely defined by the +existing Linux `/proc` interface -- no design considerations necessary. + +**Note**: We already have several applications for this task. + +Possible mentors: Olaf Buddenhagen (antrik) + +Exercise: Add or fix one piece in the existing procfs translator. + +*Status*: Madhusudan.C.S has implemented a new, fully functional [[procfs|madhusudancs]] for +GSoC 2008. He is still working on some outstanding issues. + +--- + +Note that [[jkoenig's `procfs` re-write|hurd/translator/procfs/jkoenig]] should +address all these issues already. diff --git a/community/gsoc/project_ideas/secure_chroot.mdwn b/community/gsoc/project_ideas/secure_chroot.mdwn index 57739861..bfaf330b 100644 --- a/community/gsoc/project_ideas/secure_chroot.mdwn +++ b/community/gsoc/project_ideas/secure_chroot.mdwn @@ -12,7 +12,7 @@ License|/fdl]]."]]"""]] [[!meta title="Secure chroot Implementation"]] As the Hurd attempts to be (almost) fully [[UNIX]]-compatible, it also implements a -`chroot` [[system call]]. However, the current implementation is not really +`chroot()` [[system call]]. However, the current implementation is not really good, as it allows easily escaping the `chroot`, for example by use of [[passive_translators|hurd/translator]]. diff --git a/community/gsoc/project_ideas/testing_framework.mdwn b/community/gsoc/project_ideas/testing_framework.mdwn new file mode 100644 index 00000000..ff9899d9 --- /dev/null +++ b/community/gsoc/project_ideas/testing_framework.mdwn @@ -0,0 +1,55 @@ +[[!meta copyright="Copyright © 2011 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="Automated Testing Framework"]] + +Hurd development would benefit greatly from automated tests. +Unit tests should be added for all the major components +(Mach; Hurd servers and libraries). +Also, functional tests can be performed on various levels: +Mach; individual servers; and interaction of several servers. + +(The highest level would actually be testing libc functionality, +which in turn uses the various Hurd mechanisms. +glibc already comes with a test suite -- +though it might be desirabe to add some extra tests +for exercising specific aspects of the Hurd...) + +Our page on [[automated testing|open_issues/unit_testing]] collects some relevant material. + +The Goal of this task is to provide testing frameworks +that allow automatically running tests +as part of the Hurd and Mach build processes. +The student will have to create the necessary infrastrucure, +and a couple of sample tests employing it. +Ideally, all the aspects mentioned above should be covered. +At least some have to be ready for use and upstream merging +before the end of the summer. + +(As a bonus, +in addition to these explicit tests, +it would be helpful to integrate some methods +for testing [[locking validity|libdiskfs_locking]], +performing static code analysis etc.) + +This task probably requires some previous experience +with unit testing of C programs, +as well as dealing with complex build systems. +No in-depth knowledge about any specific parts of the Hurd should be necessary, +but some general understanding of the Hurd architecture +will have to be aquired to complete this project. +This makes it a very good project +to get started on Hurd development :-) + +Possible mentors: ? + +Exercise: Create a program performing some simple test(s) on the Hurd or Mach code. +It doesn't need to be integrated in the build process yet -- +a standalone progrem with it's own Makefile is fine for now. diff --git a/community/gsoc/project_ideas/testing_framework/discussion.mdwn b/community/gsoc/project_ideas/testing_framework/discussion.mdwn new file mode 100644 index 00000000..872d0eb7 --- /dev/null +++ b/community/gsoc/project_ideas/testing_framework/discussion.mdwn @@ -0,0 +1,270 @@ +[[!meta copyright="Copyright © 2010, 2011 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]]."]]"""]] + +freenode, #hurd channel, 2011-03-05: + + <nixness> what about testing though? + <nixness> like sort of "what's missing? lets write tests for it so that + when someone gets to implementing it, he knows what to do. Repeat" + project + <antrik> you mean creating an automated testing framework? + <antrik> this is actually a task I want to add for this year, if I get + around to it :-) + <nixness> yeah I'd very much want to apply for that one + <nixness> cuz I've never done Kernel hacking before, but I know that with + the right tasks like "test VM functionality", I would be able to write up + the automated tests and hopefully learn more about what breaks/makes the + kernel + <nixness> (and it would make implementing the feature much less hand-wavy + and more correct) + <nixness> antrik, I believe the framework(CUnit right?) exists, but we just + need to write the tests. + <antrik> do you have prior experience implementing automated tests? + <nixness> lots of tests! + <nixness> yes, in Java mostly, but I've played around with CUnit + <antrik> ah, great :-) + <nixness> here's what I know from experience: 1) write basic tests. 2) + write ones that test multiple features 3) stress test [option 4) + benchmark and record to DB] + <youpi> well, what we'd rather need is to fix the issues we already know + from the existing testsuites :) + +[[GSoC project propsal|community/gsoc/project_ideas/testsuites]]. + + <nixness> youpi, true, and I think I should check what's available in way + of tests, but if the tests are "all or nothing" then it becomes really + hard to fix your mistakes + <youpi> they're not all or nothing + <antrik> youpi: the existing testsuites don't test specific system features + <youpi> libc ones do + <youpi> we could also check posixtestsuite which does too + +[[open_issues/open_posix_test_suite]]. + + <antrik> AFAIK libc has very few failing tests + +[[open_issues/glibc_testsuite]]. + + <youpi> err, like twenty? + <youpi> € grep -v '^#' expected-results-i486-gnu-libc | wc -l + <youpi> 67 + <youpi> nope, even more + <antrik> oh, sorry, I confused it with coreutils + <pinotree> plus the binutils ones, i guess + <youpi> yes + +[[open_issues/binutils#weak]]. + + <antrik> anyways, I don't think relying on external testsuites for + regression testing is a good plan + <antrik> also, that doesn't cover unit testing at all + <youpi> why ? + <youpi> sure there can be unit testing at the translator etc. level + <antrik> if we want to implement test-driven development, and/or do serious + refactoring without too much risk, we need a test harness where we can + add specific tests as needed + <youpi> but more than often, the issues are at the libc / etc. level + because of a combination o fthings at the translator level, which unit + testing won't find out + * nixness yewzzz! + <nixness> sure unit testing can find them out. if they're good "unit" tests + <youpi> the problem is that you don't necessarily know what "good" means + <youpi> e.g. for posix correctness + <youpi> since it's not posix + <nixness> but if they're composite clever tests, then you lose that + granularity + <nixness> youpi, is that a blackbox test intended to be run at the very end + to check if you're posix compliant? + <antrik> also, if we have our own test harness, we can run tests + automatically as part of the build process, which is a great plus IMHO + <youpi> nixness: "that" = ? + <nixness> oh nvm, I thought there was a test stuie called "posix + correctness" + <youpi> there's the posixtestsuite yes + <youpi> it's an external one however + <youpi> antrik: being external doesn't mean we can't invoke it + automatically as part of the build process when it's available + <nixness> youpi, but being internal means it can test the inner workings of + certain modules that you are unsure of, and not just the interface + <youpi> sure, that's why I said it'd be useful too + <youpi> but as I said too, most bugs I've seen were not easy to find out at + the unit level + <youpi> but rather at the libc level + <antrik> of course we can integrate external tests if they exist and are + suitable. but that that doesn't preclude adding our own ones too. in + either case, that integration work has to be done too + <youpi> again, I've never said I was against internal testsuite + <antrik> also, the major purpose of a test suite is checking known + behaviour. a low-level test won't directly point to a POSIX violation; + but it will catch any changes in behaviour that would lead to one + <youpi> what I said is that it will be hard to write them tight enough to + find bugs + <youpi> again, the problem is knowing what will lead to a POSIX violation + <youpi> it's long work + <youpi> while libc / posixtestsuite / etc. already do that + <antrik> *any* unexpected change in behaviour is likely to cause bugs + somewher + <youpi> but WHAT is "expected" ? + <youpi> THAT is the issue + <youpi> and libc/posixtessuite do know that + <youpi> at the translator level we don't really + <youpi> see the recent post about link() + +[link(dir,name) should fail with +EPERM](http://lists.gnu.org/archive/html/bug-hurd/2011-03/msg00007.html) + + <youpi> in my memory jkoenig pointed it out for a lot of such calls + <youpi> and that issue is clearly not known at the translator level + <nixness> so you're saying that the tests have to be really really + low-level, and work our way up? + <youpi> I'm saying that the translator level tests will be difficult to + write + <antrik> why isn't it known at the translator level? if it's a translator + (not libc) bug, than obviously the translator must return something wrong + at some point, and that's something we can check + <youpi> because you'll have to know all the details of the combinations + used in libc, to know whether they'll lead to posix issues + <youpi> antrik: sure, but how did we detect that that was unexpected + behavior? + <youpi> because of a glib test + <youpi> at the translator level we didn't know it was an unexpected + behavior + <antrik> gnulib actually + <youpi> and if you had asked me, I wouldn't have known + <antrik> again, we do *not* write a test suite to find existing bugs + <youpi> right, took one for the other + <youpi> doesn't really matter actually + <youpi> antrik: ok, I don't care then + <antrik> we write a test suite to prevent future bugs, or track status of + known bugs + <youpi> (don't care *enough* for now, I mean) + <nixness> hmm, so write something up antrik for GSoC :) and I'll be sure to + apply + <antrik> now that we know some translators return a wrong error status in a + particular situation, we can write a test that checks exactly this error + status. that way we know when it is fixed, and also when it breaks again + <antrik> nixness: great :-) + <nixness> sweet. that kind of thing would also need a db backend + <antrik> nixness: BTW, if you have a good idea, you can send an application + for it even if it's not listed among the proposed tasks... + <antrik> so you don't strictly need a writeup from me to apply for this :-) + <nixness> antrik, I'll keep that in mind, but I'll also be checking your + draft page + <nixness> oh cool :) + <antrik> (and it's a well known fact that those projects which students + proposed themselfs tend to be the most successful ones :-) ) + * nixness draft initiated + <antrik> youpi: BTW, I'm surprised that you didn't mention libc testsuite + before... working up from there is probably a more effective plan than + starting with high-level test suites like Python etc... + <youpi> wasn't it already in the gsoc proposal? + <youpi> bummer + <antrik> nope + +freenode, #hurd channel, 2011-03-06: + + <nixness> how's the hurd coding workflow, typically? + +*nixness* -> *foocraft*. + + <foocraft> we're discussing how TDD can work with Hurd (or general kernel + development) on #osdev + <foocraft> so what I wanted to know, since I haven't dealt much with GNU + Hurd, is how do you guys go about coding, in this case + <tschwinge> Our current workflow scheme is... well... is... + <tschwinge> Someone wants to work on something, or spots a bug, then works + on it, submits a patch, and 0 to 10 years later it is applied. + <tschwinge> Roughly. + <foocraft> hmm so there's no indicator of whether things broke with that + patch + <foocraft> and how low do you think we can get with tests? A friend of mine + was telling me that with kernel dev, you really don't know whether, for + instance, the stack even exists, and a lot of things that I, as a + programmer, can assume while writing code break when it comes to writing + kernel code + <foocraft> Autotest seems promising + +See autotest link given above. + + <foocraft> but in any case, coming up with the testing framework that + doesn't break when the OS itself breaks is hard, it seems + <foocraft> not sure if autotest isolates the mistakes in the os from + finding their way in the validity of the tests themselves + <youpi> it could be interesting to have scripts that automatically start a + sub-hurd to do the tests + +[[hurd/subhurd#unit_testing]]. + + <tschwinge> foocraft: To answer one of your earlier questions: you can do + really low-level testing. Like testing Mach's message passing. A + million times. The questions is whether that makes sense. And / or if + it makes sense to do that as part of a unit testing framework. Or rather + do such things manually once you suspect an error somewhere. + <tschwinge> The reason for the latter may be that Mach IPC is already + heavily tested during normal system operation. + <tschwinge> And yet, there still may be (there are, surely) bugs. + <tschwinge> But I guess that you have to stop at some (arbitrary?) level. + <foocraft> so we'd assume it works, and test from there + <tschwinge> Otherwise you'd be implementing the exact counter-part of what + you're testing. + <tschwinge> Which may be what you want, or may be not. Or it may just not + be feasible. + <foocraft> maybe the testing framework should have dependencies + <foocraft> which we can automate using make, and phony targets that run + tests + <foocraft> so everyone writes a test suite and says that it depends on A + and B working correctly + <foocraft> then it'd go try to run the tests for A etc. + <tschwinge> Hmm, isn't that -- on a high level -- have you have by + different packages? For example, the perl testsuite depends (inherently) + on glibc working properly. A perl program's testsuite depends on perl + working properly. + <foocraft> yeah, but afaik, the ordering is done by hand + +freenode, #hurd channel, 2011-03-07: + + <antrik> actually, I think for most tests it would be better not to use a + subhurd... that leads precisely to the problem that if something is + broken, you might have a hard time running the tests at all :-) + <antrik> foocraft: most of the Hurd code isn't really low-level. you can + use normal debugging and testing methods + <antrik> gnumach of course *does* have some low-level stuff, so if you add + unit tests to gnumach too, you might run into issues :-) + <antrik> tschwinge: I think testing IPC is a good thing. as I already said, + automated testing is *not* to discover existing but unknown bugs, but to + prevent new ones creeping in, and tracking progress on known bugs + <antrik> tschwinge: I think you are confusing unit testing and regression + testing. http://www.bddebian.com/~hurd-web/open_issues/unit_testing/ + talks about unit testing, but a lot (most?) of it is actually about + regression tests... + <tschwinge> antrik: That may certainly be -- I'm not at all an expert in + this, and just generally though that some sort of automated testing is + needed, and thus started collecting ideas. + <tschwinge> antrik: You're of course invited to fix that. + +IRC, freenode, #hurd, 2011-03-08 + +(After discussing the [[open_issues/anatomy_of_a_hurd_system]].) + + <antrik> so that's what your question is actually about? + <foocraft> so what I would imagine is a set of only-this-server tests for + each server, and then we can have fun adding composite tests + <foocraft> thus making debugging the composite scenarios a bit less tricky + <antrik> indeed + <foocraft> and if you were trying to pass a composite test, it would also + help knowing that you still didn't break the server-only test + <antrik> there are so many different things that can be tested... the + summer will only suffice to dip into this really :-) + <foocraft> yeah, I'm designing my proposal to focus on 1) make/use a + testing framework that fits the Hurd case very well 2) write some tests + and docs on how to write good tests + <antrik> well, doesn't have to be *one* framework... unit testing and + regression testing are quite different things, which can be covered by + different frameworks diff --git a/community/gsoc/project_ideas/testsuites.mdwn b/community/gsoc/project_ideas/testsuites.mdwn index 7cb7d103..f5ee2084 100644 --- a/community/gsoc/project_ideas/testsuites.mdwn +++ b/community/gsoc/project_ideas/testsuites.mdwn @@ -1,20 +1,27 @@ -[[!meta copyright="Copyright © 2010 Free Software Foundation, Inc."]] +[[!meta copyright="Copyright © 2010, 2011 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]]."]]"""]] +is included in the section entitled [[GNU Free Documentation +License|/fdl]]."]]"""]] [[!meta title="Fix Compatibility Problems Exposed by Testsuites"]] A number of software packages come with extensive testsuites. -Some notable ones are libc, Perl, Python, GNU Coreutils, and glib. +Some notable ones are [[glibc|open_issues/glibc_testsuite]], gnulib, Perl, +Python, GNU Coreutils, and glib. While these testsuites were written mostly to track regressions in the respective packages, some of the tests fail on the Hurd in general. +There is also the [[Open POSIX Testsuite|open_issues/open_posix_test_suite]] +which is more of a whole system interface testing suite. + +Then, there is the [[open_issues/File_System_Exerciser]] which we can use to +test our file system servers for conformity. + While in some cases these might point to wrong usage of system interfaces, most of the time such failures are actually caused by shortcomings in Hurd's implementation of these interfaces. These shortcomings are often not obvious in normal use, @@ -42,6 +49,9 @@ While tracking down the various issues, the student will be digging into the inner workings of the Hurd, and thus gradually gaining the knowledge required for Hurd development in general. +A complementary task is adding a proper [[open_issues/unit_testing]] framework +to the GNU Hurd's code base, and related packages. + Possible mentors: Samuel Thibault (youpi) Exercise: Take a stab at one of the testsuite failures, diff --git a/community/gsoc/project_ideas/valgrind.mdwn b/community/gsoc/project_ideas/valgrind.mdwn new file mode 100644 index 00000000..e9e94857 --- /dev/null +++ b/community/gsoc/project_ideas/valgrind.mdwn @@ -0,0 +1,83 @@ +[[!meta copyright="Copyright © 2009, 2010, 2011 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="Porting Valgrind to the Hurd"]] + +[[!tag open_issue_gnumach open_issue_hurd]] + +[Valgrind](http://valgrind.org/) is an extremely useful debugging tool for memory errors. +(And some other kinds of hard-to-find errors too.) +Aside from being useful for program development in general, +a Hurd port will help finding out why certain programs segfault on the Hurd, +although they work on Linux. +Even more importantly, it will help finding bugs in the Hurd servers themselfs. + +To keep track of memory use, +Valgrind however needs to know how each [[system call]] affects the validity of memory regions. +This knowledge is highly kernel-specific, +and thus Valgrind needs to be explicitely ported for every system. + +Such a port involves two major steps: +making Valgrind understand how kernel traps work in general on the system in question; +and how all the individual kernel calls affect memory. +The latter step is where most of the work is, +as the behaviour of each single [[system call]] needs to be described. + +Compared to Linux, +[[microkernel/Mach]] (the microkernel used by the Hurd) has very few kernel traps. +Almost all [[system call]]s are implemented as [[RPC]]s instead -- +either handled by Mach itself, or by the various [[Hurd servers|hurd/translator]]. +All RPCs use a pair of `mach_msg()` invocations: +one to send a request message, and one to receive a reply. +However, while all RPCs use the same `mach_msg()` trap, +the actual effect of the call varies greatly depending on which RPC is invoked -- +similar to the `ioctl()` call on Linux. +Each request thus must be handled individually. + +Unlike `ioctl()`, +the RPC invocations have explicit type information for the parameters though, +which can be retrieved from the message header. +By analyzing the parameters of the RPC reply message, +Valgrind can know exactly which memory regions are affected by that call, +even without specific knowledge of the RPC in question. +Thus implementing a general parser for the reply messages +will already give Valgrind a fairly good approximation of memory validity -- +without having to specify the exact semantic of each RPC by hand. + +While this should make Valgrind quite usable on the Hurd already, it's not perfect: +some RPCs might return a buffer that is only partially filled with valid data; +or some reply parameters might be optional, +and only contain valid data under certain conditions. +Such specific semantics can't be deduced from the message headers alone. +Thus for a complete port, +it will still be necessary to go through the list of all known RPCs, +and implement special handling in Valgrind for those RPCs that need it. + +The goal of this task is at minimum to make Valgrind grok Mach traps, +and to implement the generic RPC handler. +Ideally, specific handling for RPCs needing it should also be implemented. + +Completing this project will require digging into Valgrind's handling of [[system call]]s, +and into Hurd RPCs. +It is not an easy task, but a fairly predictable one -- +there shouldn't be any unexpected difficulties, +and no major design work is necessary. +It doesn't require any specific previous knowledge: +only good programming skills in general. +On the other hand, +the student will obtain a good understanding of Hurd RPCs while working on this task, +and thus perfect qualifications for Hurd development in general :-) + +Possible mentors: Samuel Thibault (youpi) + +Exercise: As a starter, +students can try to teach valgrind a couple of Linux ioctls, +as this will make them learn how to use the read/write primitives of valgrind. |