-10 Numerous capitalization, punctuation, spelling, or grammar errors
DESIGN
+ -5 Gratuitous use of malloc()
-10 Failure to check return value of malloc()
-10 Use of ASSERT to check something that can actually fail, e.g. malloc()
+ -2: ASSERT() on user provided input (thread niceness)
+ -2: Re-enabling interrupts instead of returning them to their old value
CODING STYLE
-10 Inconsistent or bad coding style: no indentation, cramming
-2 A1: Forgot to include some declarations [which]
-5 A2: Missing/non-responsive/too long/too short
-5 A3: Missing/non-responsive/too long/too short
+ -5 A3: "non-responsive" if only mentioned micro optimizations, e.g. not
+ double checking conditions
-5 A4: Missing/non-responsive/too long/too short
-5 A5: Missing/non-responsive/too long/too short
+ -5 A5: correct mechanism but incorrect reasoning
-5 A6: Missing/non-responsive/too long/too short
-3 A6: "Straw man"--comparing correct design to an incorrect one
-10 Claim or implication that list operations are atomic
-10 Interrupt handler always examines or modifies every waiting thread
-5 Race between list modification and interrupt handler
-10 A timer tick that occurs during list modification delays waking
- threads until the next timer tick
+ threads until the next timer tick
-10 Race between two threads modifying list
-10 Wakes only one thread even if multiple are finished sleeping
-15 Malfunctions (e.g. by busy waiting or not waiting the full time),
- even in corner case (e.g. when malloc() returns NULL)
+ even in corner case (e.g. when malloc() returns NULL)
-15 Fixed limit on number of threads that may sleep
- -5 Uses thread_block() instead of higher-level synchronization primitives
-5 Disables interrupts unnecessarily
-5 Unnecessary or redundant synchronization in timer_sleep()
+ -5 Implementation split across timer.c and thread.[ch]
+ -2 Doesn\92t check thread priorities when waking threads that cause
+ scheduling changes
+ -3 Checks for wakeups in \91schedule\92 and not \91timer_tick/thread_tick\92.
+ Hence there are a lot of spurious checks each time schedule is called.
+ This is probably why the tests passed too since the checks were too
+ frequent anyway.
+ -2 Interrupts turned off and on instead of storing the current level
+ and restoring the old level.
Total deductions (capped at -30): XXX
-15 Grossly simplified design egregiously limits generality, e.g. small,
fixed limit on total number of donations, donees, donor locks, etc.
-5 Global list of donations is unnecessary and inefficient
+ -5 Donated priority is more than priority of donor
-3 sema_up() yields regardless of whether a higher-priority
thread was unblocked
-5 sema_up() yields even when it does not unblock a thread
-8 Race in lock_acquire() between priority donation and "down"ing sema
-8 Race in lock_release() between release of donated pri and "up"ing sema
+ -10 Races in priority management code in general, i.e. no protection
+ when walking/updating priority graph
Total deductions (capped at -30): XXX
once per second is unreadable
-5 Code to update load average, recent_cpu, and thread priorities
once per second is difficult to read
- -5 Wastefully recalculates every thread's priority every 4th timer tick
+ -0 Wastefully recalculates every thread's priority every 4th timer tick
-5 Race against timer interrupt in thread_get_recent_cpu()
or thread_get_load_avg()
+ -5 Failing to recompute current thread\92s priority every 4 ticks
+
Total deductions (capped at -30): XXX
Total score (100 - deductions): YYY
+
projects / pintos-anon / blobdiff