@chapter Project 1: Threads
In this assignment, we give you a minimally functional thread system.
@chapter Project 1: Threads
In this assignment, we give you a minimally functional thread system.
Before you read the description of this project, you should read all of
the following sections: @ref{Introduction}, @ref{Coding Standards},
@ref{Debugging Tools}, and @ref{Development Tools}. You should at least
Before you read the description of this project, you should read all of
the following sections: @ref{Introduction}, @ref{Coding Standards},
@ref{Debugging Tools}, and @ref{Development Tools}. You should at least
-skim the material in @ref{Threads Tour} and especially
-@ref{Synchronization}. To complete this project you will also need to
-read @ref{4.4BSD Scheduler}.
+skim the material from @ref{Pintos Loading} through @ref{Memory
+Allocation}, especially @ref{Synchronization}. To complete this project
+you will also need to read @ref{4.4BSD Scheduler}.
-Basic thread support. Much of your work will take place in these
-files. @file{thread.h} defines @struct{thread}, which you are likely
-to modify in all four projects. See @ref{struct thread} and @ref{Thread
-Support} for more information.
+Basic thread support. Much of your work will take place in these files.
+@file{thread.h} defines @struct{thread}, which you are likely to modify
+in all four projects. See @ref{struct thread} and @ref{Threads} for
+more information.
Functions for I/O port access. This is mostly used by source code in
the @file{devices} directory that you won't have to touch.
Functions for I/O port access. This is mostly used by source code in
the @file{devices} directory that you won't have to touch.
-@item mmu.h
-Functions and macros related to memory management, including page
-directories and page tables. This will be more important to you in
-project 3. For now, you can ignore it.
+@item vaddr.h
+@itemx pte.h
+Functions and macros for working with virtual addresses and page table
+entries. These will be more important to you in project 3. For now,
+you can ignore them.
-You may need to add or modify code where interrupts are already
-disabled, such as in @func{sema_up} or @func{sema_down}. You should
-still try to keep this code as short as you can.
+The synchronization primitives themselves in @file{synch.c} are
+implemented by disabling interrupts. You may need to increase the
+amount of code that runs with interrupts disabled here, but you should
+still try to keep it to a minimum.
Disabling interrupts can be useful for debugging, if you want to make
sure that a section of code is not interrupted. You should remove
Disabling interrupts can be useful for debugging, if you want to make
sure that a section of code is not interrupted. You should remove
to immediately yield the CPU.
Thread priorities range from @code{PRI_MIN} (0) to @code{PRI_MAX} (63).
to immediately yield the CPU.
Thread priorities range from @code{PRI_MIN} (0) to @code{PRI_MAX} (63).
-Lower numbers correspond to @emph{higher} priorities, so that priority 0
-is the highest priority and priority 63 is the lowest.
+Lower numbers correspond to lower priorities, so that priority 0
+is the lowest priority and priority 63 is the highest.
The initial thread priority is passed as an argument to
@func{thread_create}. If there's no reason to choose another
priority, use @code{PRI_DEFAULT} (31). The @code{PRI_} macros are
The initial thread priority is passed as an argument to
@func{thread_create}. If there's no reason to choose another
priority, use @code{PRI_DEFAULT} (31). The @code{PRI_} macros are
running until it blocks or finishes, even if it calls
@func{thread_yield}.
If multiple threads have the same highest priority,
running until it blocks or finishes, even if it calls
@func{thread_yield}.
If multiple threads have the same highest priority,
Priority donation only changes the priority of the donee
thread. The donor thread's priority is unchanged.
Priority donation only changes the priority of the donee
thread. The donor thread's priority is unchanged.
-Priority donation is not additive: if thread @var{A} (with priority 3) donates
-to thread @var{B} (with priority 5), then @var{B}'s new priority is 3, not 8.
+Priority donation is not additive: if thread @var{A} (with priority 5) donates
+to thread @var{B} (with priority 3), then @var{B}'s new priority is 5, not 8.
-Yes, that's fine. It's easiest to describe the algorithm in terms of 64
-separate queues, but that doesn't mean you have to implement it that
-way.
-
-If you use a single queue, it should probably be sorted.
+Yes. In general, your implementation may differ from the description,
+as long as its behavior is the same.
projects / pintos-anon / blobdiff