The free lunch is over

1. The Free Lunch Is Over

2. The Free Lunch Is Over
A Fundamental Turn Toward
Concurrency in Software
(By Herb Sutter)

3. Presenter
Muhammad Rizwan
Sr. Software Engineer
muhammad.rizwan@techlogix.xom
+92 51 111 859 859 Ext 108

4. Agenda
• Moore's Law
• Amdahl's law
• Performance Factors
• Free Lunch
• Power Wall
• Free Lunch is Over
• Conclusion
• Future
• References

5. Moors Law

6. Moor’s Law
• Over the history of computing hardware,
the number of transistors on integrated
circuits doubles approximately every two
years Transistor
Count
If the current trend continues
to 2020, the number of
transistors would reach 32
billion.

7. Amdahl's law

8. Amdahl's law
The speedup of a
program using
multiple processors
in parallel
computing is limited
by the sequential
fraction of the
program.
For example, if 95% of the program can
be parallelized, the theoretical maximum
speedup using parallel computing would
be 20× as shown in the diagram, no
matter how many processors are used

9. Performance Factors

10. Performance Factors
Clock Speed
Execution Optimization
Cache

11. Free Lunch
What Free Lunch Is Actually?

12. Free Lunch
Programmers haven't
really had to worry
much about
performance or
concurrency because
of Moore's Law
The traditional approach
to application
performance was to
simply wait for the next
generation of processor;
most software
developers did not need
to invest in performance
tuning, and enjoyed a
“free lunch” from
hardware
improvements.
Why we did not see 4GHz
processors in Market?

13. Power Wall

14. Power Wall

16. Power Wall

17. Power Wall
This Free Lunch is Over
Right Now…

18. Free Lunch is Over
Your free lunch will soon be over. What can you do about it?
What are you doing about it?

19. The major processor manufacturers and
architectures, from Intel and AMD to Sparc and
PowerPC, have run out of room with most of their
traditional approaches to boosting CPU performance.
Instead of driving clock speeds and straight-line
instruction throughput ever higher, they are instead
turning toward hyper threading and multicore
architectures
Chip designers are under so much pressure to
deliver ever-faster CPUs that they’ll risk changing
the meaning of your program, and possibly break
it, in order to make it run faster

20. Conclusion

21.  The free lunch is over
 Performance Free Lunch
 Moore’s law has changed
Futurists such as Ray Kurzweil, Bruce Sterling, and Vernor Vinge believe that the
exponential improvement described by Moore's law will ultimately lead to a technological
singularity: a period where progress in technology occurs almost instantly.
 Amdahl’s law demands shift in software
concepts
 Factors
 Hyper threading
 Multicore
 Cache

22. Future

26. Now ball is in programmers
court

27. -> With multicore processors, programs written in sequential mode will no longer
surf on the wave of this generation processors.
->To surf in new wave, programs need to be well writtenparallel.
-> Programming language and systemwill increasingly be forced to deal well
with concurrency.
-> Concurrency is the next major revolution in how we write software.
->Applications will increasingly need to be concurrent if they want to fully exploit
continuing exponential CPU throughput gains.
-> Efficiency and performanceoptimization will get more, not less, important.

28. New Law
Only Parallel Applications
Will Survive

29. References

30. References
The Free Lunch Is Over By Herb Sutter
A Fundamental Turn Toward Concurrency in Software
The Free Lunch Is Over By Ricardo Hermann , Thadeo Carmo
Developing Concurrent Software
Is the free lunch really over? Scalability in
Many-core Systems By Michael Wrinn
The Price of Free Lunch
Programming in Multicore Era

31. Any Question?