README
1this is a multithreaded disk i/o microbenchmark. it requires O_DIRECT,
2pread/pwrite, and pthreads.
3
4WARNING: this will destroy data if used incorrectly.
5
6usage: ./randomio filename nr_threads write_fraction_of_io fsync_fraction_of_writes io_size nr_seconds_between_samples
7
8filename
9 filename or device to read/write.
10
11write_fraction_of_io
12 what fraction of i/o should be writes. for example 0.25 for
13 25% write traffic.
14
15fsync_fraction_of_writes
16 what fraction of writes should be fsync'd.
17
18io_size
19 how many bytes to read/write. must be a positive multiple
20 of 512 bytes
21
22nr_seconds_between_samples
23 how many seconds to average samples over. recommended 10 or
24 more.
25
26
27for example:
28
29% ./randomio /dev/sdb 8 0.5 1 4096 10
30 total | read: latency (ms) | write: latency (ms)
31 iops | iops min avg max sdev | iops min avg max sdev
32-------+----------------------------------+---------------------------------
33 86.9 | 43.2 5.9 134.4 494.4 94.2 | 43.7 0.3 49.0 335.9 53.2
34 85.4 | 40.9 7.7 146.8 831.4 103.3 | 44.5 0.3 45.2 243.0 44.8
35 84.5 | 43.2 4.2 138.4 1126.4 112.5 | 41.3 0.2 46.8 263.2 50.7
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