MCQ IN COMPUTER SCIENCE & ENGINEERING

Detailed explanation-1: -Even with infinite number of processors, maximum speedup limited to 1/f . Example: With only 5% of computation being serial, maximum speedup is 20, irrespective of number of processors.

Detailed explanation-2: -First, the addition of more processor cores doesn’t automatically improve computer performance. The OS and applications must direct software program instructions to recognize and use the multiple cores. This must be done in parallel, using various threads to different cores within the processor package.

Detailed explanation-3: -Hints: Consider that the execution time of program in the machine before enhancement (without enhancement) is T. Then find the total execution time after the enhancements, T’. The speedup is T/T’. (50/100x1/2) because 50% was enhanced by 2 times and same goes to the 4 times.

Detailed explanation-4: -The obtained results conclude that speedup is directly proportional to the number of CPU cores, such that using a hexa-core CPU in lieu of a dual-core CPU can achieve a speedup up to twice as fast. Thus, utilizing powerful multi-core CPU’s could rival the use of parallelism on a standard CPU.