Final Exam Flashcards
How does Prime and Probe work? What’s the difference between it and Flush and Reload
Prime - Accesses all cache ways, mark time spent on access. Probe - Perform Prime again, if it’s faster then it’s not data we want. If it’s slower, then we GOT IT
First Fit Allocation
Iterate through blocks until you find one with enough free space.
Explicit vs. implicit Free list
Implicit Free list has a header for every block, Explicit Free List has a header for free blocks and Faster allocation when Heap is full/low fragmentation.
Where do new/modified pointers go in a tri color garbage collection
Grey box
Which boxes are removed most frequently in general garbage collection
Youngest generation
How do boxes go from younger to older generations?
When they get full, garbage collection -> Move it to the next generation.
When are oldest generation boxes garbage collected?
When they get full
Do all processes have a parent?
Not Init, it has no parent but the rest do
What signal do Childs send to say they died?
Sigchild
How to kill a process?
Send it a sigkill signal
Does every object have a viable?
No, not every class has a viable, non virtual ones don’t.
Do vtables contain non virtual methods?
No they only contain virtual functions.
Does every class have a vtable?
Only classes with virtual member functions have a vtable
What does garbage collection remove?
Unreachable data via pointers.
Cache ways vs cache sets
Cache sets are cache lines with the same index.
Ways are number of lines to iterate through
Requirements for flush and load and why?
Must have the same physical space in cache for collision, so it can time the load to the flushed address and acquire the bit.
How does Flush and Reload work
Flush, Wait, Measure time to reload that line, fast -> access, slow -> no access, Repeat.
How to get data from Flush and Reload accesses?
Has two lines for 0 and 1, if it’s quicker to access one or the other, that determines which one it is.
Why does Prime and Probe not need to share the same physical space?
Spy can just prime some lines for the address space of the victim, victim must load to one of those lines.
What is the connection between Hark Links and Inodes
Connect directly to the file’s Inode, stay connected even if it moves, contribute to reference count. (Not To Directory)
What is a Soft Link
Contains a separate Inode Value that points to the original file, breaks when file deleted, only file path.
