@func{schedule} doesn't exist, which is arguably a @command{gdb} bug.
You can work around this by setting the breakpoint by filename and
line number, e.g.@: @code{break thread.c:@var{ln}} where @var{ln} is
-the line number of the first declaration in @func{schedule}.
-Alternatively you can recompile with optimization turned off, by
-removing @samp{-O3} from the @code{CFLAGS} line in
-@file{Make.config}.} Be sure to keep track of each thread's address
+the line number of the first declaration in @func{schedule}.} Be sure
+to keep track of each thread's address
and state, and what procedures are on the call stack for each thread.
You will notice that when one thread calls @func{switch_threads},
another thread starts running, and the first thing the new thread does
@node Tips
@section Tips
+@itemize @bullet
+@item
There should be no busy-waiting in any of your solutions to this
-assignment. Furthermore, resist the temptation to directly disable
-interrupts in your solution by calling @func{intr_disable} or
+assignment.
+
+@item
+Do your best to resist the temptation to directly disable interrupts
+in your solution by calling @func{intr_disable} or
@func{intr_set_level}, although you may find doing so to be useful
while debugging. Instead, use semaphores, locks and condition
-variables to solve synchronization problems. Hint: read the comments
-in @file{threads/synch.h} if you're unsure what synchronization
+variables to solve synchronization problems. Read the tour section on
+synchronization (@pxref{Synchronization}) or the comments in
+@file{threads/synch.h} if you're unsure what synchronization
primitives may be used in what situations.
Given some designs of some problems, there may be one or two instances
in which it is appropriate to directly change the interrupt levels
-instead of relying on the given synchroniztion primitives. This must
+instead of relying on the given synchronization primitives. This must
be justified in your @file{DESIGNDOC} file. If you're not sure you're
justified, ask!
-While all parts of this assignment are required if you intend to earn
-full credit on this project, keep in mind that Problem 1-2 (Join) will
-be needed for future assignments, so you'll want to get this one
-right. We don't give out solutions, so you're stuck with your Join
-code for the whole quarter. Problem 1-1 (Alarm Clock) could be very
-handy, but not strictly required in the future. The upshot of all
-this is that you should focus heavily on making sure that your
-implementation of @func{thread_join} works correctly, since if it's
-broken, you will need to fix it for future assignments. The other
-parts can be turned off in the future if you find you can't make them
-work quite right.
-
-Also keep in mind that Problem 1-4 (the MLFQS) builds on the features you
-implement in Problem 1-3, so to avoid unnecessary code duplication, it
+@item
+All parts of this assignment are required if you intend to earn full
+credit on this project. However, some will be more important in
+future projects:
+
+@itemize @minus
+@item
+Problem 1-1 (Alarm Clock) could be handy for later projects, but it is
+not strictly required.
+
+@item
+Problem 1-2 (Join) will be needed for future projects. We don't give
+out solutions, so to avoid extra work later you should make sure that
+your implementation of @func{thread_join} works correctly.
+
+@item
+Problems 1-3 and 1-4 won't be needed for later projects.
+@end itemize
+
+@item
+Problem 1-4 (MLFQS) builds on the features you
+implement in Problem 1-3. To avoid unnecessary code duplication, it
would be a good idea to divide up the work among your team members
such that you have Problem 1-3 fully working before you begin to tackle
Problem 1-4.
+@end itemize
@node Problem 1-1 Alarm Clock
@section Problem 1-1: Alarm Clock
the lock, then recall the donation once it has acquired the lock.
Implement this fix.
-You will need to account for all different orders that priority
+You will need to account for all different orders in which priority
donation and inversion can occur. Be sure to handle multiple
donations, in which multiple priorities are donated to a thread. You
must also handle nested donation: given high, medium, and low priority
@item
Examples of synchronization mechanisms have been presented in lecture.
Going over these examples should help you understand when each type is
-useful or needed.
+useful or needed. @xref{Synchronization}, for specific information
+about synchronization in Pintos.
@end enumerate
@item
@anchor{Out of Order 1-1}
This test is inherently full of race conditions. On a real system it
-wouldn't work perfectly all the time either. However, you can help it
-work more reliably:
+wouldn't work perfectly all the time either. There are a few ways you
+can help it work more reliably:
@itemize @bullet
@item
@item
Make the timer tick more slowly by decreasing @code{TIMER_FREQ} in
@file{timer.h} to its minimum value of 19.
-
-@item
-Increase the serial output speed to the maximum of 115,200 bps by
-modifying the call to @func{set_serial} in @func{serial_init_poll} in
-@file{devices/serial.c}.
@end itemize
The former two changes are only desirable for testing problem 1-1 and
possibly 1-3. You should revert them before working on other parts
-of the project or turn in the project. The latter is harmless, so you
-can retain it or revert it at your option.
+of the project or turn in the project.
@item
@b{Should @file{p1-1.c} be expected to work with the MLFQS turned on?}
projects / pintos-anon / blobdiff