@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
@section Tips
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
-@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
-primitives may be used in what situations.
+assignment. Furthermore, to the greatest extent possible, 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. 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
could potentially be used more profitably by another thread. Your
solution should not busy wait.
-The argument to @func{timer_sleep} is expressed in timer ticks, not
-in milliseconds or another unit. There are @code{TIMER_FREQ} timer
+The argument to @func{timer_sleep} is expressed in timer ticks, not in
+milliseconds or any another unit. There are @code{TIMER_FREQ} timer
ticks per second, where @code{TIMER_FREQ} is a macro defined in
@code{devices/timer.h}.
+Separate functions @func{timer_msleep}, @func{timer_usleep}, and
+@func{timer_nsleep} do exist for sleeping a specific number of
+milliseconds, microseconds, or nanoseconds, respectively, but these will
+call @func{timer_sleep} automatically when necessary. You do not need
+to modify them.
+
If your delays seem too short or too long, reread the explanation of the
@option{-r} option to @command{pintos} (@pxref{Debugging versus
Testing}).
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