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32 .\" @(#)tests.ms 6.2 (Berkeley) 4/16/91
33 .\" $FreeBSD: src/share/doc/papers/diskperf/tests.ms,v 1.5 1999/08/28 00:18:04 peter Exp $
34 .\" $DragonFly: src/share/doc/papers/diskperf/tests.ms,v 1.2 2003/06/17 04:36:56 dillon Exp $
40 Our battery of tests consists of four programs,
41 read_8192, write_8192, write_4096
42 and rewrite_8192 originally written by [McKusick83]
43 to evaluate the performance of the new file system in 4.2BSD.
44 These programs all follow the same model and are typified by
55 for (i = 0; i < 1024; i++)
59 The remaining programs are included in appendix A.
61 These programs read, write with two different blocking factors,
62 and rewrite logical files in structured file system on the disk
64 The write programs create new files while the rewrite program
65 overwrites an existing file.
66 Each of these programs represents an important segment of the
67 typical UNIX file system activity with the read program
68 representing by far the largest class and the rewrite the smallest.
70 A blocking factor of 8192 is used by all programs except write_4096.
71 This is typical of most 4.2BSD user programs since a standard set of
72 I/O support routines is commonly used and these routines buffer
73 data in similar block sizes.
75 For each test run, a empty eight Kilobyte block
76 file system was created in the target
78 Then each of the four tests was run and timed.
79 Each test was run three times;
80 the first to clear out any useful data in the cache,
81 and the second two to insure that the experiment
82 had stablized and was repeatable.
83 Each test operated on eight Megabytes of data to
84 insure that the cache did not overly influence the results.
85 Another file system was then initialized using a
86 basic blocking factor of four Kilobytes and the same tests
87 were run again and timed.
88 A command script for a run appears as follows:
92 echo "8K/1K file system"
93 newfs /dev/rhp0g eagle
96 echo "write_8192 /mnt0/foo/tst2"
98 write_8192 /mnt0/foo/tst2
100 write_8192 /mnt0/foo/tst2
102 write_8192 /mnt0/foo/tst2
103 echo "read_8192 /mnt0/foo/tst2"
104 read_8192 /mnt0/foo/tst2
105 read_8192 /mnt0/foo/tst2
106 read_8192 /mnt0/foo/tst2