133 lines
4.5 KiB
Text
133 lines
4.5 KiB
Text
Writing a Test
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==============
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Writing a test program is pretty easy. Basically, a test is configured via
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a monster array in the Run script, which specifics (among other things) the
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program to execute and the parameters to pass it.
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The test itself is simply a program which is given the optional parameters
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on the command line, and produces logging data on stdout and its results on
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stderr.
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============================================================================
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Test Configuration
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==================
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In Run, all tests are named in the "$testList" array. This names the
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individual tests, and also sets up aliases for groups of tests, eg. "index".
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The test specifications are in the "$testParams" array. This contains the
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details of each individual test as a hash. The fields in the hash are:
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* "logmsg": the full name to display for this test.
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* "cat": the category this test belongs to; must be configured
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in $testCats.
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* "prog": the name of the program to execute; defaults to the name of
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the benchmark.
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* "repeat": number of passes to run; either 'short' (the default),
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'long', or 'single'. For 'short' and 'long', the actual numbers of
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passes are given by $shortIterCount and $longIterCount, which are
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configured at the top of the script or by the "-i" flag. 'single'
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means just run one pass; this should be used for test which do their
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own multi-pass handling internally.
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* "stdout": non-0 to add the test's stdout to the log file; defaults to 1.
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Set to 0 for tests that are too wordy.
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* "stdin": name of a file to send to the program's stdin; default null.
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* "options": options to be put on the program's command line; default null.
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============================================================================
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Output Format
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=============
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The results on stderr take the form of a line header and fields, separated
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by "|" characters. A result line can be one of:
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COUNT|score|timebase|label
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TIME|seconds
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ERROR|message
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Any other text on stderr is treated as if it were:
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ERROR|text
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Any output to stdout is placed in a log file, and can be used for debugging.
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COUNT
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-----
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The COUNT line is the line used to report a test score.
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* "score" is the result, typically the number of loops performed during
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the run
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* "timebase" is the time base used for the final report to the user. A
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value of 1 reports the score as is; a value of 60, for example, divides
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the time taken by 60 to get loops per minute. Atimebase of zero indicates
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that the score is already a rate, ie. a count of things per second.
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* "label" is the label to use for the score; like "lps" (loops per
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second), etc.
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TIME
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----
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The TIME line is optionally used to report the time taken. The Run script
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normally measures this, but if your test has signifant overhead outside the
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actual test loop, you should use TIME to report the time taken for the actual
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test. The argument is the time in seconds in floating-point.
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ERROR
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-----
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The argument is an error message; this will abort the benchmarking run and
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display the message.
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Any output to stderr which is not a formatted line will be treated as an
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error message, so use of ERROR is optional.
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============================================================================
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Test Examples
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=============
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Iteration Count
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---------------
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The simplest thing is to count the number of loops executed in a given time;
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see eg. arith.c. The utlilty functions in timeit.c can be used to implement
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the fixed time interval, which is generally passed in on the command line.
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The result is reported simply as the number of iterations completed:
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fprintf(stderr,"COUNT|%lu|1|lps\n", iterations);
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The bnenchmark framework will measure the time taken itself. If the test
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code has significant overhead (eg. a "pump-priming" pass), then you should
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explicitly report the time taken for the test by adding a line like this:
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fprintf(stderr, "TIME|%.1f\n", seconds);
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If you want results reported as loops per minute, then set timebase to 60:
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fprintf(stderr,"COUNT|%lu|60|lpm\n", iterations);
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Note that this only affects the final report; all times passed to or
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from the test are still in seconds.
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Rate
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----
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The other technique is to calculate the rate (things per second) in the test,
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and report that directly. To do this, just set timebase to 0:
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fprintf(stderr, "COUNT|%ld|0|KBps\n", kbytes_per_sec);
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Again, you can use TIME to explicitly report the time taken:
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fprintf(stderr, "TIME|%.1f\n", end - start);
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but this isn't so important since you've already calculated the rate.
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