Performance

Notes

• In section 1.6 they make an attempt to quantify performance
  • They have experience in this.
  • And this is what drives making better architecture.
• Performance is tricky
  • Some computations may be cpu bound, thus the processor is most important
  • Some may be disk bound,
  • Or I/O bound
• The best performance for a computational scientist is radically different from the best performance for a bank or insurance company.
• Performance measures are important as a marketing tool at least
• What determines performance?
• I like the table on page 29

  • Airplane	Passenger capacity	Range (miles)	Speed (mph)	Throughput (passengers × mph)
    Boeing 777	375	4,630	610	228,750
    Boeing 747	470	4,150	610	286,700
    Concorde	132	4,000	1,350	178,200
    Douglas DC-8-50	146	8,720	544	79,424
    Boeing 737 -10	230	5,740	522	120,060
    Airbus A320	194	3,500	536	103,982

  • I added the Boeing 737 and the Airbus A320
  • The look at several different raw measures of performance for various types of airplanes.
    • The 747 has the highest capacity
    • The DC-8 has the largest range
    • The Concorde is the fastest
  • They discuss how each of these measures leads to a different "best" plane.
    • I think, if you want to move a small number of passengers quickly you should use the now defunct Concorde.
    • If you want to move a large number of passengers should shore probably consider the 747
    • If you want to move passengers a long way, the Douglas DC8 is probably your choice.
  • Yet none of these make the top used list.
  • But the 737-10 is the most commonly used plane today, closely followed by the Airbus
  • Can you think of anything else we might want to know about these planes when comparing?
  • In the end, the 737 uses far less fuel than the 747
• Notice, even the derived measurement, Throughput, does not predict this.
• Can you think of any other derived measurements you might want to compute?
• What are some characteristics of a computer that you might want to (may have in the past) consider?