Fundamentals of Quantitative Design and Analysis - Computer Architecture: A Quantitative Approach - page 3

FIGURE 1.1 Growth in processor performance since the late 1970s . This chart plots per-
formance relative to the VAX 11/780 as measured by the SPEC benchmarks (see Section
1.8 ). Prior to the mid-1980s, processor performance growth was largely technology driven and
averaged about 25% per year. The increase in growth to about 52% since then is attributable
to more advanced architectural and organizational ideas. By 2003, this growth led to a differ-
ence in performance of about a factor of 25 versus if we had continued at the 25% rate. Per-
formance for floating-point-oriented calculations has increased even faster. Since 2003, the
limits of power and available instruction-level parallelism have slowed uniprocessor perform-
ance, to no more than 22% per year, or about 5 times slower than had we continued at 52%
per year. (The fastest SPEC performance since 2007 has had automatic parallelization turned
on with increasing number of cores per chip each year, so uniprocessor speed is harder to
gauge. These results are limited to single-socket systems to reduce the impact of automatic
parallelization.) Figure 1.11 on page 24 shows the improvement in clock rates for these same
three eras. Since SPEC has changed over the years, performance of newer machines is es-
timated by a scaling factor that relates the performance for two different versions of SPEC
(e.g., SPEC89, SPEC92, SPEC95, SPEC2000, and SPEC2006).
The effect of this dramatic growth rate in the 20th century has been fourfold. First, it has
signiicantly enhanced the capability available to computer users. For many applications, the
highest-performance microprocessors of today outperform the supercomputer of less than 10
years ago.
Second, this dramatic improvement in cost-performance leads to new classes of computers.
Personal computers and workstations emerged in the 1980s with the availability of the micro-
processor. The last decade saw the rise of smart cell phones and tablet computers, which many
people are using as their primary computing platforms instead of PCs. These mobile client
devices are increasingly using the Internet to access warehouses containing tens of thousands
of servers, which are being designed as if they were a single gigantic computer.