A multithreaded web server wishes to keep track of the number of requests it services (known as hits). Consider the two following
strategies to prevent a race condition on the variable hits. The first
strategy is to use a basic mutex lock when updating hits:

int hits;
mutex lock hit lock;

hit lock. acquire();
hits++;
hit lock. release();

A second strategy is to use an atomic integer:

atomic t hits;
atomic inc(&hits);

Explain which of these two strategies is more efficient.