Topic:
collecting statistics on a UserInterface
Topic:
function cost
Topic:
execution profile
Topic:
software metrics
Topic:
statistics
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Summary
Through statistical analysis of programs, researchers have found limited use of most statement types. For instance, in one study 45% of all statements were replacements of which 75% used only a variable or a constant. These studies indicate that language capability seldom matches language use. In a statistical study of machine code, 35% of the code was load instructions for memory access. (cbb 5/80)
Subtopic: sampling 
| Quote: use sampling to test for assertion failures across a large user base [»liblB6_2003]
| | Quote: sample code execution as a Bernoulli process using pre-generated random countdowns; fast path is a decrement, compare, and branch [»liblB6_2003]
| | Quote: use event counts instead of event traces when sampling over a large user base [»liblB6_2003]
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Subtopic: common fragments
| Quote: large program frequently reuse small sequences of instructions
| | Quote: copy-paste segments of 5-15 lines, 12% copied a function, 2/3 renamed a variable, 1/4 modified a statement [»liZ3_2006]
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Subtopic: conditionals vs. lines-of-code
| Quote: for white-box testing, count IF statements instead of LOC; measures the number of executable paths [»yamaT11_1998]
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Subtopic: intermediate language vs. source
| Quote: compared intermediate code instead of C code; captures the essential properties of a program [»engbJ5_1999]
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Subtopic: program statistics
| Quote: the global coupling of 17 kernel modules grows exponentially with version number; lines of code grows linearly with version number; leads to maintenance issues [»schaSR2_2002]
| | Quote: program statistics for variables, parameters, assignments, constants, arrays, operators [»cookRP3_1982, OK]
| | QuoteRef: knutDE1_1971 ;;7 distribution of statement types (FORTRAN) assignment (41-50%), if,goto, call between 14% and 8%, rest small
| | QuoteRef: alexWG2_1972 ;;15 assignment statements 42% of the time
| | Quote: in a large Fortran library, 58% of instructions were assignments of which half had no operators and a third one operator [»hennMA7_1980, OK]
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Subtopic: inner loops
| QuoteRef: clarBL9_1973 ;;54 Knuth 71 and Alexander 72: typical programs spend > 50% times executing < 4% of code
| | QuoteRef: knutDE1_1971 ;;13 less than 4% of program uses more than 50% of time
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Subtopic: simple vs. complex
| Quote: about 75% of UNIX shell programs consisted of straight-line scripts [»mashJR_1976]
| | Quote: simple constructs predominate in SAL programs
| | QuoteRef: knutDE1_1971 ;;9 almost all assignments very simple e.g. a=b or a=b+c e.g., 40% of additions were a+1
| | QuoteRef: knutDE1_1971 ;;8 95% do loops used increment of 1
| | QuoteRef: alexWG2_1972 ;;23 equivalence 46% of the time
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Subtopic: procedure depth
| QuoteRef: alexWG2_1972 ;;18 80% of procedures one level deep
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Subtopic: embedded programs
| Quote: embedded programs use unsigned 8/16-bit data; SpecInt95 programs use signed and unsigned 32-bit data [»engbJ5_1999]
| | Quote: embedded programs use logic and arithmetic instructions; SpecInt95 programs use 5x as many arithmetic instructions
| | Quote: 35% of embedded functions are void f(void); i.e., for side effects
| | Quote: most data (by amount) is global for SpecInt95 and embedded programs [»engbJ5_1999]
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Subtopic: machine code statistics
| Quote: statistics from a million Mesa instructions: 17% load immediate, 13% load local, 7% store local, etc. [»sweeRE3_1982, OK]
| | Quote: collected machine statistics for several months; 35% LOAD, 18% conditional branch, 14% return, 9% arith., 6% jump, 5% STORE [»baraAM3_1978, OK]
| | Quote: execution statistics of 13% MOVL instructions in compiled VAX code [»wiecCA3_1982, OK]
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Related Topics
Topic: collecting statistics on a UserInterface (12 items)
Topic: function cost (8 items)
Topic: execution profile (43 items)
Topic: software metrics (32 items)
Topic: statistics
(12 items)
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