Large buffers vs Large static buffers, is there an advantage?

Question

Consider the following code.

Is DoSomething1() faster then DoSomething2() in a 1000 consecutive executions? I would assume that if I where to call DoSomething1() it 1000 times it would be faster then calling DoSomething2() it 1000 times.

Is there any disadvantage to making all my large buffers static?

#define MAX_BUFFER_LENGTH 1024*5 
void DoSomething1()
{
    static char buf[MAX_BUFFER_LENGTH] ; 
    memset( buf, 0, MAX_BUFFER_LENGTH );
}

void DoSomething2()
{
    char buf[MAX_BUFFER_LENGTH] ; 
    memset( buf, 0, MAX_BUFFER_LENGTH );
}

Thank you for your time.

Answer 1

Disadvantage of static buffers:

• If you need to be thread safe then using static buffers probably isn't a good idea.
• Memory won't be freed until the end of your program hence making your memory consumption higher.

Advantages of static buffers:

• There are less allocations with static buffers. You don't need to allocate on the stack each time.
• With a static buffer, there is less chance of a stack overflow from too high of an allocation.