DOC PREVIEW
CMU CS 15213 - Introduction to Computer Systems

This preview shows page 1-2 out of 6 pages.

Save
View full document
Premium Document
Do you want full access? Go Premium and unlock all 6 pages.
Access to all documents
Download any document
Ad free experience

Unformatted text preview:

Course Theme 15 213 The Class That Gives CMU Its Zip Abstraction is good but don t forget reality Courses to date emphasize abstraction Introduction to Computer Systems Abstract data types Asymptotic analysis These abstractions have limits Randal E Bryant August 30 2006 Especially in the presence of bugs Need to understand underlying implementations Useful outcomes Topics Theme Five great realities of computer systems How this fits within CS curriculum Become more effective programmers Able to find and eliminate bugs efficiently Able to tune program performance Prepare for later systems classes in CS ECE Compilers Operating Systems Networks Computer Architecture Embedded Systems class01a ppt 15 213 F 06 2 Great Reality 1 Computer Arithmetic Int Int s are not Integers Float Float s are not Reals Does not generate random values Examples Yes Int s Due to finiteness of representations Integer operations satisfy ring properties Floating point operations satisfy ordering properties Commutativity associativity distributivity 40000 40000 1600000000 50000 50000 Is x y z x y z Unsigned Signed Int s Monotonicity values of signs Yes Observation Float s 1e20 1e20 3 14 3 14 1e20 1e20 3 14 3 Arithmetic operations have important mathematical properties Cannot assume usual usual properties Is x2 0 Float s 15 213 F 06 15 213 F 06 4 Need to understand which abstractions apply in which contexts Important issues for compiler writers and serious application programmers 15 213 F 06 Great Reality 2 Assembly Code Example You You ve got to know assembly Time Stamp Counter Chances are you you ll never write program in assembly Compilers are much better more patient than you are Understanding assembly key to machinemachine level execution model Special 64 bit register in Intel compatible machines Incremented every clock cycle Read with rdtsc instruction Application Behavior of programs in presence of bugs Tuning program performance double t start counter P t get counter printf P required f clock cycles n t Understanding sources of program inefficiency Implementing system software Compiler has machine code as target Operating systems must manage process state Creating fighting malware x86 assembly is the language of choice 5 15 213 F 06 Code to Read Counter 15 213 F 06 6 Great Reality 3 Write small amount of assembly code using GCC s asm facility Inserts assembly code into machine code generated by compiler static unsigned cyc hi 0 static unsigned cyc lo 0 Memory Matters Random Access Memory is an unun physical abstraction Memory is not unbounded Set hi and lo to the high and low order bits of the cycle counter void access counter unsigned hi unsigned lo asm rdtsc movl edx 0 movl eax 1 r hi r lo edx eax 7 Measure time required by procedure In units of clock cycles High level language model breaks down 15 213 F 06 It must be allocated and managed Many applications are memory dominated Memory referencing bugs especially pernicious Effects are distant in both time and space Memory performance is not uniform 8 Cache and virtual memory effects can greatly affect program performance Adapting program to characteristics of memory system can lead to major speed improvements 15 213 F 06 Memory Referencing Bug Example Referencing Bug Explanation double double fun int fun int i i volatile volatile double double d 1 d 1 3 14 3 14 volatile volatile long long int int a 2 a 2 a i a i 1073741824 1073741824 Possibly Possibly out out of of bounds bounds return return d 0 d 0 fun 0 fun 0 fun 1 fun 1 fun 2 fun 2 fun 3 fun 3 fun 4 fun 4 3 14 3 14 3 14 3 14 3 1399998664856 3 1399998664856 2 00000061035156 2 00000061035156 3 14 3 14 then thensegmentation segmentationfault fault 15 213 F 06 9 Memory Referencing Errors C and C do not provide any memory protection Out of bounds array references Invalid pointer values Abuses of malloc free Can lead to nasty bugs Whether or not bug has any effect depends on system and compiler Action at a distance 11 Understand what possible interactions may occur Use or develop tools to detect referencing errors d3 d0 2 a 1 1 a 0 0 Location accessed by fun i C does not implement bounds checking Out of range write can affect other parts of program state 15 213 F 06 void copyij int int int i j for i 0 i for j 0 dst i j src 2048 2048 dst 2048 2048 2048 i j 2048 j src i j 59 393 288 clock cycles void copyji int int int i j for j 0 j for i 0 dst i j src 2048 2048 dst 2048 2048 2048 j i 2048 i src i j 1 277 877 876 clock cycles 21 5 times slower How can I deal with this 3 Memory System Performance Example Effect of bug may be first observed long after it is generated Program in Java Lisp or ML 4 d7 d4 10 Corrupted object logically unrelated to one being accessed Saved State Hierarchical memory organization Performance depends on access patterns Measured on 2GHz Intel Pentium 4 Including how step through multi dimensional array 15 213 F 06 12 15 213 F 06 The Memory Mountain Memory Performance Example 1200 Read throughput MB s copyij 1000 L1 Pentium III Xeon 550 MHz 16 KB on chip L1 d cache 16 KB on chip L1 i cache 512 KB off chip unified L2 cache Implementations of Matrix Multiplication copyji ijk ijk for for i 0 i 0 i n i n i i for j 0 for j 0 j n j n j j sum sum 0 0 0 0 for for k 0 k 0 k n k n k k sum sum a i k a i k b k j b k j c i j sum c i j sum Multiple ways to nest loops 800 600 400 xe L2 200 2k 8k 32k 128k 512k 2m 8m s13 s15 s9 Stride words s11 s5 Mem s7 s1 s3 0 Working set size bytes 15 213 F 06 13 Matmult Performance Alpha 21164 Too big for L1 Cache jik jik for for j 0 j 0 j n j n j j for i 0 for i 0 i n i n i i sum sum 0 0 0 0 for for k 0 k 0 k n k n k k sum sum a i k a i k b k j b k j c i j sum c i j sum 15 213 F 06 14 Blocked matmult perf Alpha 21164 Too big for L2 Cache 160 160 140 140 120 120 ijk 100 100 ikj bijk jik 80 bikj 80 jki ijk kij 60 kji ikj 60 40 40 20 20 0 0 50 matrix size n 75 100 125 150 175 200 225 250 275 300 325 350 375 400 425 450 475 500 matrix size n 15 15 213 F 06 16 15 213 F 06 Great Reality 4 Great Reality 5 There There s more to performance than asymptotic complexity Computers do more than …


View Full Document

CMU CS 15213 - Introduction to Computer Systems

Documents in this Course
lecture

lecture

14 pages

lecture

lecture

46 pages

Caches

Caches

9 pages

lecture

lecture

39 pages

Lecture

Lecture

36 pages

Lecture

Lecture

45 pages

Lecture

Lecture

56 pages

lecture

lecture

11 pages

lecture

lecture

9 pages

Lecture

Lecture

36 pages

Lecture

Lecture

37 pages

Exam

Exam

16 pages

Lecture

Lecture

10 pages

Lecture

Lecture

43 pages

Lecture

Lecture

8 pages

Lecture

Lecture

8 pages

Lecture

Lecture

36 pages

Lecture

Lecture

43 pages

Lecture

Lecture

12 pages

Lecture

Lecture

37 pages

Lecture

Lecture

6 pages

Lecture

Lecture

40 pages

coding

coding

2 pages

Exam

Exam

17 pages

Exam

Exam

14 pages

Lecture

Lecture

29 pages

Lecture

Lecture

34 pages

Exam

Exam

11 pages

Lecture

Lecture

9 pages

Lecture

Lecture

37 pages

Lecture

Lecture

36 pages

lecture

lecture

46 pages

Lecture

Lecture

33 pages

Lecture

Lecture

57 pages

Lecture

Lecture

32 pages

Lecture

Lecture

46 pages

Lecture

Lecture

40 pages

Lecture

Lecture

11 pages

Lecture

Lecture

6 pages

Lecture

Lecture

43 pages

Lecture

Lecture

12 pages

Lecture

Lecture

18 pages

Exam

Exam

10 pages

Lecture

Lecture

45 pages

Lecture

Lecture

37 pages

Exam

Exam

24 pages

class09

class09

21 pages

class22

class22

37 pages

class20

class20

30 pages

class27

class27

33 pages

class25

class25

21 pages

class04

class04

31 pages

Lecture

Lecture

59 pages

class01a

class01a

14 pages

class12

class12

45 pages

class29

class29

33 pages

Lecture

Lecture

39 pages

Lecture

Lecture

6 pages

class03

class03

34 pages

lecture

lecture

42 pages

Lecture

Lecture

40 pages

Lecture

Lecture

47 pages

Exam

Exam

19 pages

R06-B

R06-B

25 pages

class17

class17

37 pages

class25

class25

31 pages

Lecture

Lecture

15 pages

final-f06

final-f06

17 pages

Lecture

Lecture

9 pages

lecture

lecture

9 pages

Exam

Exam

15 pages

Lecture

Lecture

22 pages

class11

class11

45 pages

lecture

lecture

50 pages

Linking

Linking

37 pages

Lecture

Lecture

64 pages

Integers

Integers

40 pages

Exam

Exam

11 pages

Lecture

Lecture

37 pages

Lecture

Lecture

44 pages

Lecture

Lecture

37 pages

Lecture

Lecture

9 pages

Lecture

Lecture

37 pages

Lecture

Lecture

45 pages

Final

Final

25 pages

lecture

lecture

9 pages

Lecture

Lecture

30 pages

Lecture

Lecture

16 pages

Final

Final

17 pages

Lecture

Lecture

8 pages

Exam

Exam

11 pages

Lecture

Lecture

47 pages

Lecture

Lecture

9 pages

lecture

lecture

39 pages

Exam

Exam

11 pages

lecture

lecture

41 pages

lecture

lecture

37 pages

Lecture

Lecture

59 pages

Lecture

Lecture

45 pages

Exam 1

Exam 1

18 pages

Lecture

Lecture

41 pages

Lecture

Lecture

32 pages

Lecture

Lecture

30 pages

Lecture

Lecture

9 pages

Lecture

Lecture

9 pages

Lecture

Lecture

15 pages

Lecture

Lecture

11 pages

Lecture

Lecture

9 pages

Lecture

Lecture

34 pages

Lecture

Lecture

40 pages

Lecture

Lecture

4 pages

Lecture

Lecture

46 pages

Lecture

Lecture

8 pages

Lecture

Lecture

65 pages

Lecture

Lecture

38 pages

Lecture

Lecture

35 pages

Lecture

Lecture

8 pages

Lecture

Lecture

34 pages

Lecture

Lecture

8 pages

Exam

Exam

13 pages

Lecture

Lecture

43 pages

Lecture

Lecture

9 pages

Lecture

Lecture

12 pages

Lecture

Lecture

9 pages

Lecture

Lecture

34 pages

Lecture

Lecture

43 pages

Lecture

Lecture

7 pages

Lecture

Lecture

45 pages

Lecture

Lecture

24 pages

Lecture

Lecture

47 pages

Lecture

Lecture

12 pages

Lecture

Lecture

20 pages

Lecture

Lecture

9 pages

Exam

Exam

11 pages

Lecture

Lecture

52 pages

Lecture

Lecture

20 pages

Exam

Exam

11 pages

Lecture

Lecture

35 pages

Lecture

Lecture

47 pages

Lecture

Lecture

18 pages

Lecture

Lecture

30 pages

Lecture

Lecture

59 pages

Lecture

Lecture

37 pages

Lecture

Lecture

22 pages

Lecture

Lecture

35 pages

Exam

Exam

23 pages

Lecture

Lecture

9 pages

Lecture

Lecture

22 pages

class12

class12

32 pages

Lecture

Lecture

8 pages

Lecture

Lecture

39 pages

Lecture

Lecture

44 pages

Lecture

Lecture

38 pages

Lecture

Lecture

69 pages

Lecture

Lecture

41 pages

Lecture

Lecture

12 pages

Lecture

Lecture

52 pages

Lecture

Lecture

59 pages

Lecture

Lecture

39 pages

Lecture

Lecture

83 pages

Lecture

Lecture

59 pages

class01b

class01b

17 pages

Exam

Exam

21 pages

class07

class07

47 pages

Lecture

Lecture

11 pages

Odyssey

Odyssey

18 pages

multicore

multicore

66 pages

Lecture

Lecture

6 pages

lecture

lecture

41 pages

lecture

lecture

55 pages

lecture

lecture

52 pages

lecture

lecture

33 pages

lecture

lecture

46 pages

lecture

lecture

55 pages

lecture

lecture

17 pages

lecture

lecture

49 pages

Exam

Exam

17 pages

lecture

lecture

56 pages

Exam 2

Exam 2

16 pages

Exam 2

Exam 2

16 pages

Notes

Notes

37 pages

Lecture

Lecture

40 pages

Lecture

Lecture

36 pages

Lecture

Lecture

43 pages

Lecture

Lecture

25 pages

Exam

Exam

13 pages

Lecture

Lecture

32 pages

Lecture

Lecture

12 pages

Lecture

Lecture

58 pages

Lecture

Lecture

29 pages

Lecture

Lecture

59 pages

Lecture

Lecture

41 pages

Lecture

Lecture

50 pages

Exam

Exam

17 pages

Lecture

Lecture

29 pages

Lecture

Lecture

44 pages

Lecture

Lecture

41 pages

Lecture

Lecture

52 pages

Lecture

Lecture

40 pages

Lecture

Lecture

33 pages

lecture

lecture

10 pages

Lecture

Lecture

27 pages

Lecture

Lecture

29 pages

Lecture

Lecture

39 pages

Lecture

Lecture

9 pages

Lecture

Lecture

29 pages

Lecture

Lecture

8 pages

Lecture

Lecture

43 pages

Lecture

Lecture

43 pages

Lecture

Lecture

75 pages

Lecture

Lecture

55 pages

Exam

Exam

12 pages

Lecture

Lecture

43 pages

Lecture

Lecture

35 pages

lecture

lecture

36 pages

Exam

Exam

33 pages

lecture

lecture

56 pages

lecture

lecture

64 pages

lecture

lecture

8 pages

Exam

Exam

14 pages

Lecture

Lecture

43 pages

Lecture

Lecture

36 pages

lecture

lecture

56 pages

lecture

lecture

75 pages

lecture

lecture

36 pages

Lecture

Lecture

50 pages

Lecture

Lecture

45 pages

Lecture

Lecture

13 pages

Exam

Exam

23 pages

Lecture

Lecture

10 pages

Lecture

Lecture

48 pages

Lecture

Lecture

83 pages

lecture

lecture

57 pages

Lecture

Lecture

33 pages

Lecture

Lecture

39 pages

Lecture

Lecture

33 pages

lecture

lecture

54 pages

Lecture

Lecture

30 pages

Exam

Exam

13 pages

Lecture

Lecture

36 pages

Lecture

Lecture

40 pages

Exam

Exam

17 pages

Lecture

Lecture

9 pages

Exam

Exam

15 pages

Lecture

Lecture

44 pages

Lecture

Lecture

34 pages

Lecture

Lecture

24 pages

Lecture

Lecture

29 pages

class12

class12

43 pages

lecture

lecture

43 pages

class22

class22

22 pages

R06-B

R06-B

25 pages

class01b

class01b

19 pages

lecture

lecture

29 pages

lab1

lab1

8 pages

Caches

Caches

36 pages

lecture

lecture

55 pages

Lecture,

Lecture,

37 pages

Integers

Integers

40 pages

Linking

Linking

38 pages

lecture

lecture

45 pages

Lecture

Lecture

61 pages

Linking

Linking

33 pages

lecture

lecture

40 pages

lecture

lecture

40 pages

Lecture

Lecture

32 pages

lecture

lecture

48 pages

lecture

lecture

44 pages

Exam

Exam

11 pages

Lecture

Lecture

31 pages

Lecture

Lecture

46 pages

Lecture

Lecture

40 pages

Lecture

Lecture

40 pages

Exam

Exam

12 pages

Lecture

Lecture

42 pages

Lecture

Lecture

36 pages

Lecture

Lecture

45 pages

Lecture

Lecture

41 pages

Lecture

Lecture

13 pages

Lecture

Lecture

35 pages

Lecture

Lecture

20 pages

Final

Final

19 pages

Lecture

Lecture

33 pages

Lecture

Lecture

50 pages

Lecture

Lecture

33 pages

Lecture

Lecture

27 pages

Lecture

Lecture

6 pages

Exam

Exam

15 pages

Lecture

Lecture

24 pages

Lecture

Lecture

23 pages

Lecture

Lecture

43 pages

Lecture

Lecture

32 pages

Lecture

Lecture

52 pages

Lecture

Lecture

37 pages

Lecture

Lecture

36 pages

Lecture

Lecture

34 pages

Lecture

Lecture

40 pages

Lecture

Lecture

15 pages

lecture

lecture

21 pages

Lecture

Lecture

58 pages

Lecture

Lecture

49 pages

Lecture

Lecture

36 pages

Lecture

Lecture

11 pages

Lecture

Lecture

12 pages

Lecture

Lecture

58 pages

Lecture

Lecture

33 pages

Exam

Exam

15 pages

Lecture

Lecture

35 pages

Lecture

Lecture

10 pages

Lecture

Lecture

25 pages

Lecture

Lecture

31 pages

Lecture

Lecture

24 pages

Lecture

Lecture

34 pages

Lecture

Lecture

50 pages

lecture

lecture

35 pages

Lecture

Lecture

11 pages

Lecture

Lecture

39 pages

Lecture

Lecture

45 pages

Lecture

Lecture

41 pages

exam1-f05

exam1-f05

11 pages

Lecture

Lecture

4 pages

Lecture

Lecture

17 pages

Exam

Exam

17 pages

malloc()

malloc()

12 pages

Lecture

Lecture

57 pages

Lecture

Lecture

30 pages

Lecture

Lecture

30 pages

Lecture

Lecture

47 pages

Lecture

Lecture

33 pages

Exam

Exam

12 pages

Lecture

Lecture

43 pages

Lectures

Lectures

33 pages

Lecture

Lecture

36 pages

lecture

lecture

33 pages

Exam

Exam

14 pages

Lecture

Lecture

43 pages

Lecture

Lecture

25 pages

Load more
Download Introduction to Computer Systems
Our administrator received your request to download this document. We will send you the file to your email shortly.
Loading Unlocking...
Login

Join to view Introduction to Computer Systems and access 3M+ class-specific study document.

or
We will never post anything without your permission.
Don't have an account?
Sign Up

Join to view Introduction to Computer Systems and access 3M+ class-specific study document.

or

By creating an account you agree to our Privacy Policy and Terms Of Use

Already a member?