Lock-Free interview questions

1. A.a strategy that proceeds without locking, assuming no conflict, then validates at commit time and retries if another writer interfered
2. B.the strongest non-blocking guarantee, ensuring every thread finishes its operation in a bounded number of steps regardless of others
3. C.an atomic instruction that updates a location only if it still holds an expected value, reporting success or failure to the caller
4. D.a subtle bug where a value changes from A to B and back to A, fooling a compare-and-swap into thinking nothing changed

Answer + AI explanation with Pro

1. A.ABA problem
2. B.Wait-free algorithm
3. C.Lock-free algorithm
4. D.Compare-and-swap

Answer + AI explanation with Pro

1. A.Compare-and-swap — a non-blocking design guaranteeing that at least one thread in the system always makes progress, so no single failure stalls everyone
2. B.Compare-and-swap — an atomic instruction that updates a location only if it still holds an expected value, reporting success or failure to the caller
3. C.Compare-and-swap — the strongest non-blocking guarantee, ensuring every thread finishes its operation in a bounded number of steps regardless of others
4. D.Compare-and-swap — a subtle bug where a value changes from A to B and back to A, fooling a compare-and-swap into thinking nothing changed

Answer + AI explanation with Pro

1. A.a non-blocking design guaranteeing that at least one thread in the system always makes progress, so no single failure stalls everyone
2. B.the strongest non-blocking guarantee, ensuring every thread finishes its operation in a bounded number of steps regardless of others
3. C.a strategy that proceeds without locking, assuming no conflict, then validates at commit time and retries if another writer interfered
4. D.a subtle bug where a value changes from A to B and back to A, fooling a compare-and-swap into thinking nothing changed

Answer + AI explanation with Pro

1. A.ABA problem
2. B.Optimistic concurrency
3. C.Lock-free algorithm
4. D.Compare-and-swap

Answer + AI explanation with Pro

1. A.Optimistic concurrency — a strategy that proceeds without locking, assuming no conflict, then validates at commit time and retries if another writer interfered
2. B.Optimistic concurrency — a non-blocking design guaranteeing that at least one thread in the system always makes progress, so no single failure stalls everyone
3. C.Optimistic concurrency — an atomic instruction that updates a location only if it still holds an expected value, reporting success or failure to the caller
4. D.Optimistic concurrency — the strongest non-blocking guarantee, ensuring every thread finishes its operation in a bounded number of steps regardless of others

Answer + AI explanation with Pro

1. A.a strategy that proceeds without locking, assuming no conflict, then validates at commit time and retries if another writer interfered
2. B.a non-blocking design guaranteeing that at least one thread in the system always makes progress, so no single failure stalls everyone
3. C.a subtle bug where a value changes from A to B and back to A, fooling a compare-and-swap into thinking nothing changed
4. D.an atomic instruction that updates a location only if it still holds an expected value, reporting success or failure to the caller

Answer + AI explanation with Pro

1. A.Lock-free algorithm
2. B.Compare-and-swap
3. C.Wait-free algorithm
4. D.ABA problem

Answer + AI explanation with Pro

1. A.Lock-free algorithm — a subtle bug where a value changes from A to B and back to A, fooling a compare-and-swap into thinking nothing changed
2. B.Lock-free algorithm — a non-blocking design guaranteeing that at least one thread in the system always makes progress, so no single failure stalls everyone
3. C.Lock-free algorithm — the strongest non-blocking guarantee, ensuring every thread finishes its operation in a bounded number of steps regardless of others
4. D.Lock-free algorithm — an atomic instruction that updates a location only if it still holds an expected value, reporting success or failure to the caller

Answer + AI explanation with Pro

1. A.an atomic instruction that updates a location only if it still holds an expected value, reporting success or failure to the caller
2. B.a strategy that proceeds without locking, assuming no conflict, then validates at commit time and retries if another writer interfered
3. C.the strongest non-blocking guarantee, ensuring every thread finishes its operation in a bounded number of steps regardless of others
4. D.a non-blocking design guaranteeing that at least one thread in the system always makes progress, so no single failure stalls everyone

Answer + AI explanation with Pro

1. A.Wait-free algorithm
2. B.Optimistic concurrency
3. C.Compare-and-swap
4. D.ABA problem

Answer + AI explanation with Pro

1. A.Wait-free algorithm — a subtle bug where a value changes from A to B and back to A, fooling a compare-and-swap into thinking nothing changed
2. B.Wait-free algorithm — a strategy that proceeds without locking, assuming no conflict, then validates at commit time and retries if another writer interfered
3. C.Wait-free algorithm — a non-blocking design guaranteeing that at least one thread in the system always makes progress, so no single failure stalls everyone
4. D.Wait-free algorithm — the strongest non-blocking guarantee, ensuring every thread finishes its operation in a bounded number of steps regardless of others

Answer + AI explanation with Pro

1. A.a subtle bug where a value changes from A to B and back to A, fooling a compare-and-swap into thinking nothing changed
2. B.an atomic instruction that updates a location only if it still holds an expected value, reporting success or failure to the caller
3. C.the strongest non-blocking guarantee, ensuring every thread finishes its operation in a bounded number of steps regardless of others
4. D.a strategy that proceeds without locking, assuming no conflict, then validates at commit time and retries if another writer interfered

Answer + AI explanation with Pro

1. A.ABA problem
2. B.Optimistic concurrency
3. C.Compare-and-swap
4. D.Wait-free algorithm

Answer + AI explanation with Pro

1. A.ABA problem — a subtle bug where a value changes from A to B and back to A, fooling a compare-and-swap into thinking nothing changed
2. B.ABA problem — an atomic instruction that updates a location only if it still holds an expected value, reporting success or failure to the caller
3. C.ABA problem — a strategy that proceeds without locking, assuming no conflict, then validates at commit time and retries if another writer interfered
4. D.ABA problem — the strongest non-blocking guarantee, ensuring every thread finishes its operation in a bounded number of steps regardless of others

Answer + AI explanation with Pro