How to debug user programs with gdb.

[pintos-anon] / TODO

diff --git a/TODO b/TODO
index f02d750548fb15914974bcd99d7515bcb8efb49c..7c9c42b841e0c2f820c789c315eb17f8491d751a 100644 (file)
--- a/TODO
+++ b/TODO
@@ -1,20 +1,90 @@
 -*- text -*-
 
-* Code:
+* Test pintos with GSX.
+
+* Get rid of warnings for NDEBUG build.
+
+* Need targets for checking single tests or single subdirs
+
+  - `make check' should say how to get more information
+
+  - `make recheck', `make clean-check'
+
+* Need to put time limits on tests.
+
+* Add a way for students to prints messages ignored by the autograder.
+
+  - Ignore text between /* and */.
+
+  - Allow for a comment on `exit' lines?
+
+* Improve automatic interpretation of exception messages.
+
+* Remove names from synchronization primitives?  They don't seem
+  useful in practice.
+
+* debug_backtrace() in kernel should only dereference valid pointers.
+
+* Mention how to use add-symbol-file in gdb.
+
+* We need better and more example programs.
+
+  - Need an mmap example program as a replacement for the crappy mmap FAQ
+    question.
+
+  - How about `diff' and `cmp' programs?
+
+* Threads:
+
+  - mlfqs tests suck.  They aren't even correct, e.g. the amarv
+    submission from win0405 is graded incorrectly.
+
+* Userprog project:
 
-  - Speed up disk routines: filling an 8 MB disk takes a long time.
-    (They're only slow because timer_sleep always waits for at least
-    one timer tick.)
+  - Don't emphasize that stuff needs to be copied from user space to
+    kernel space.  Instead, emphasize validation and suggest that
+    copying is a common solution and that it will be necessary in
+    project 3 and in real OSes.  Also revise the grading criteria to
+    match.
 
-  - userprog project should mark read-only pages as actually read-only
-    in the page table.  Or, since this was consistently rated as the
-    easiest project by the students, require them to do it.
+  - Mark read-only pages as actually read-only in the page table.  Or,
+    since this was consistently rated as the easiest project by the
+    students, require them to do it.
 
-  - For userprog project, don't provide per-process pagedir
-    implementation but only single-process implementation and require
-    students to implement the separation?  This project was rated as
-    the easiest after all.  Alternately we could just remove the
-    synchronization on pid selection and check that students fix it.
+  - Don't provide per-process pagedir implementation but only
+    single-process implementation and require students to implement
+    the separation?  This project was rated as the easiest after all.
+    Alternately we could just remove the synchronization on pid
+    selection and check that students fix it.
+
+* VM project:
+
+  - Discuss the perils of mixing dirty bits between kernel and user virtual
+    memory.
+
+  - Sample solution.
+
+  - Update grading/vm to reflect new mmap, munmap forms.
+
+* Filesys project:
+
+  - Increase maximum disk size from 8 MB to something that actually
+    requires doubly indirect nodes.  There is a negative pressure here
+    from the bitmap object--perhaps we need a specialized bitmap that
+    doesn't have to be all in-memory at once.
+
+    Alternatively, shrink the inode size.
+
+  - Add option to disable buffer cache.
+
+  - Sample solution.
+
+  - Need a better way to measure performance improvement of buffer
+    cache.  Some students reported that their system was slower with
+    cache--likely, Bochs doesn't simulate a disk with a realistic
+    speed.
+
+  - Clarify effect of remove(cwd).
 
 * Documentation:
 
@@ -23,22 +93,24 @@
   - Add "Digging Deeper" sections that describe the nitty-gritty x86
     details for the benefit of those interested.
 
+  - Add explanations of what "real" OSes do to give students some
+    perspective.
+
+  - GNU make 3.80 or later is required.
+
 * Assignments:
 
   - Add extra credit:
 
     . Low-level x86 stuff, like paged page tables.
 
-    . Other good ideas.
+    . Specifics on how to implement sbrk, malloc.
 
-  - The semantics of the join system call should change so that it
-    only returns the exit code once.
+    . Other good ideas.
 
-  - mmap/munmap should use segment IDs like Nachos.  Too hard
-    otherwise.
+    . opendir/readdir/closedir
 
-  - Add src/testcases/vm, src/testcases/filesys and make it clear to use
-    them?
+    . everything needed for getcwd()
 
 * Tests:
 
@@ -52,3 +124,9 @@
     too long (especially when SHOW_PROGRESS is turned on) and doesn't
     show significant improvement.
 
+* Code:
+
+  - Need an optimization barrier and an explanation of it in the
+    documentation.
+
+  - Need to check the wait system call more thoroughly.