/share/doc/papers/diskperf/tests.ms
https://bitbucket.org/freebsd/freebsd-head/ · Unknown · 109 lines · 108 code · 1 blank · 0 comment · 0 complexity · e2f9be541027c2905e339f048983afe2 MD5 · raw file
- .\" Copyright (c) 1983 The Regents of the University of California.
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- .\" @(#)tests.ms 6.2 (Berkeley) 4/16/91
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- .ds RH Tests
- .NH
- Tests
- .PP
- Our battery of tests consists of four programs,
- read_8192, write_8192, write_4096
- and rewrite_8192 originally written by [McKusick83]
- to evaluate the performance of the new file system in 4.2BSD.
- These programs all follow the same model and are typified by
- read_8192 shown here.
- .DS
- #define BUFSIZ 8192
- main( argc, argv)
- char **argv;
- {
- char buf[BUFSIZ];
- int i, j;
- j = open(argv[1], 0);
- for (i = 0; i < 1024; i++)
- read(j, buf, BUFSIZ);
- }
- .DE
- The remaining programs are included in appendix A.
- .PP
- These programs read, write with two different blocking factors,
- and rewrite logical files in structured file system on the disk
- under test.
- The write programs create new files while the rewrite program
- overwrites an existing file.
- Each of these programs represents an important segment of the
- typical UNIX file system activity with the read program
- representing by far the largest class and the rewrite the smallest.
- .PP
- A blocking factor of 8192 is used by all programs except write_4096.
- This is typical of most 4.2BSD user programs since a standard set of
- I/O support routines is commonly used and these routines buffer
- data in similar block sizes.
- .PP
- For each test run, an empty eight Kilobyte block
- file system was created in the target
- storage system.
- Then each of the four tests was run and timed.
- Each test was run three times;
- the first to clear out any useful data in the cache,
- and the second two to insure that the experiment
- had stablized and was repeatable.
- Each test operated on eight Megabytes of data to
- insure that the cache did not overly influence the results.
- Another file system was then initialized using a
- basic blocking factor of four Kilobytes and the same tests
- were run again and timed.
- A command script for a run appears as follows:
- .DS
- #!/bin/csh
- set time=2
- echo "8K/1K file system"
- newfs /dev/rhp0g eagle
- mount /dev/hp0g /mnt0
- mkdir /mnt0/foo
- echo "write_8192 /mnt0/foo/tst2"
- rm -f /mnt0/foo/tst2
- write_8192 /mnt0/foo/tst2
- rm -f /mnt0/foo/tst2
- write_8192 /mnt0/foo/tst2
- rm -f /mnt0/foo/tst2
- write_8192 /mnt0/foo/tst2
- echo "read_8192 /mnt0/foo/tst2"
- read_8192 /mnt0/foo/tst2
- read_8192 /mnt0/foo/tst2
- read_8192 /mnt0/foo/tst2
- umount /dev/hp0g
- .DE
- .ds RH Results
- .bp