Question

Consider the following C pseudo-code. The variable global sum is a globally shared variable.
Assume this is a Pthreads program and the code is part of what executes in one of the
threads.
for (i = 0; i < mymax; i++) {
global_sum += do_something(i,other-parameters);
}
(a) Explain the program execution flaw in this code. (Identify the problem and what it
potentially results in.)
(b) Show how the flaw can be fixed inside the for loop - i.e. without adding any additional
code after the loop.
(c) Show (through code or just explanation) how to address the performance problem with
the fix in part (b).