4 Written by Jens Axboe <axboe@suse.de> (initial version and kernel support) and
5 Alan D. Brunelle (threading and splitup into two seperate programs).
11 You need to be running a 2.6.13-mm1 kernel with the blk-trace patch
12 included in this repository. If you forgot where you got it, the url is:
14 rsync://rsync.kernel.org/pub/scm/linux/kernel/git/axboe/blktrace.git
16 If you don't have git, you can get hourly snapshots from:
18 http://www.kernel.org/pub/linux/kernel/people/axboe/blktrace/
20 The snapshots include the full git object database as well.
26 % blktrace -d <dev> [-o <output> -a <trace> [-a <trace>] -k]
27 -a <trace> is one of: (use multiple -a options to get more)
38 -k Kill a currently running trace.
39 --- run task to generate load to be traced ---
42 <output>_out.[0..ncpus] : Contains binary trace data
44 % blkparse -i <input> [-o <output> -s]
46 <output>.log : Contains formatted trace data, if
47 output logging is added with the -o option. Otherwise, the
48 output is sent to stdout. If the -s option is used, in
49 addition to per-CPU stats, per process stats are shown as well.
52 If you want to do live tracing, you can pipe the data between blktrace
55 % blktrace -d <device> -o - | blkparse -i -
57 This has a small risk of displaying some traces a little out of sync, since
58 it will do batch sorts of input events. Similarly, you can do traces over
59 the network with eg netcat:
61 % blktrace -d /dev/sda -o - | netcat parsehost portno
62 % netcat -l -p portno tracehost | blkparse -i -
64 Which will send the traces from tracehost to parsehost over the network on
65 the defined port number.
68 20050906, Jens Axboe <axboe@suse.de>