Comparing Intel C and Microsoft Visual C Compilers

1
Comparing Intel C and Microsoft Visual C
Compilers

• Michael Baum
• David Boyett
• Holly Garrison

2
Agenda

• Problem Statement
• System Environment
• Programs Used for Comparison
• Matrix Processing Programs Results and Analysis
• SPEC Benchmark Results and Analysis
• Conclusion

3
Problem Statement

• The general purpose of our project is to verify
  Intels claim that their compiler is 10 better
  then the Microsoft Visual compiler.
• Data will be gathered using Intel VTune tool from
  both SPEC CPU 2000 benchmarks and from simple
  matrix processing programs.

4
System Environment

• Programs were run on a single processor system
  with Intel P4 2.4GHz processor and 512 MB RAM.
• Windows 2000 operating system
• Microsoft Visual .NET compiler
• Intel C Compiler 7.1 for Windows
• Intel VTune Performance Analyzer 7.0

5
Programs Used for Comparison

• SPEC CPU 2000 Benchmark
• 164.gzip
• 300.twolf
• Simple Matrix Processing Programs
• Array Summation of 10000 elements
• Matrix Multiplication of 250x250 matrices

6
VTune Setup

• Using Intels VTune application the following
  events were measured
• Instruction Count
• Clockticks and Clockticks per Instruction
• Loads Stores
• Level 1 cache misses
• Mispredicted Calls and Branches

7
Matrix Processing Programs Results
Executable (.exe) Mispredicted Calls Mispredicted Branches 1st Level Cache Misses Loads Stores Clockticks Instruction Count Clockticks per Instruction
Array Sum 10000 (Intel) 1,518 22,285 49,890 1,268,145 844,962 18,995,295 981,030 19.36
Array Sum 10000 (VC) 4,536 39,123 186,760 863,772 1,162,239 13,069,242 1,462,053 8.94
Matrix Mult 250 (Intel) 220 5,132 0 0 657,324 9,502,532 1,979,090 4.80
Matrix Mult 250 (VC) 289 68,354 18,640,249 31,728,270 657,328 88,513,594 54,242,733 1.63
8
Matrix Processing Programs Results (cont.)
9
Matrix Processing Programs Results (cont.)
10
Matrix Processing Analysis

• For Simple Matrix and Array Processing the Intel
  compiler verified its claim of a 10 better
  compiler
• With the exception of the number of Stores
  executed, the Intel compiler showed approximately
  a 50 savings in the measured operations.
• The Matrix Multiplication program showed one
  noteworthy result the Intel compiler had zero
  events for both 1st Level Cache Misses and for
  Loads.
• Verified by multiple builds and runs

11
SPEC Benchmark Results
Executable (.exe) Mispredicted Calls Mispredicted Branches 1st Level Cache Misses Loads Stores Clockticks Instruction Count Clockticks per Instruction
164.gzip (Intel) 11,725 871,754,172 2,267,577,936 22,054,374,342 11,101,416,840 106,412,563,515 76,670,596,520 1.39
164.gzip (VC) 7,695 869,317,015 2,273,066,852 22,074,844,248 11,108,909,049 107,286,054,470 76,671,138,915 1.40
300.twolf (Intel) 346 4,874,982 7,639,211 77,060,025 32,577,657 484,933,215 210,922,988 2.30
300.twolf (VC) 537 4,797,552 7,526,588 76,831,638 33,214,416 473,946,742 211,425,444 2.24
12
SPEC Benchmark Results
13
SPEC Benchmark Results
14
SPEC CPU 2000 Analysis

• SPEC CPU 2000 Benchmarks did not show any
  significant difference between the two compilers.
• SPEC Benchmarks were re-compiled and data sets
  were collected multiple times to verify the
  validity of the original data.

15
Conclusions

• Even though our group saw significant
  improvements in performance for our small test
  programs, these same gains could not be
  duplicated for the Benchmark applications.
• These variations might be the result of
  differences in program complexity.

16
Conclusions (cont.)

• The Intel C Compiler showed results that were
  equal to or in some cases better than those of
  Microsoft Visual C.
• While Intels claim of 10 better results may not
  be true in all cases it is still a superior
  compiler.