1. block_dump (see post 73). I should mention again that you may skip creating
tempfs dir altogether.
2. find (see post 73).
3. ftrace
FTRACE
Note: ftrace should be enabled on most more or less recent systems by default.
Overall usage:
ATTENTION: overall rule - after you have traced whatever you wanted return all
values to the state they were in before trace (usually disabled)! Use "cat" to
check them beforehand.
1) sudo -i
2) enable required tracer (see below)
3) enable trace:
echo 1 > /sys/kernel/debug/tracing/tracing_on
4) see trace results:
cat /sys/kernel/debug/tracing/trace #Open as usual file.
OR
cat /sys/kernel/debug/tracing/trace_pipe #See trace results in real
time. May be piped to file. Stop viewing with Ctrl+C. NOTE: reading from this
file consumes its output.
#For example: "cat /sys/kernel/debug/tracing/trace_pipe >
/tmp/mytemp/trace_results"
5) disable trace:
echo 0 > /sys/kernel/debug/tracing/tracing_on
6) disable whatever tracer you have used ("echo 0")
7) "exit" from root shell
Tracers:
echo 1 >
/sys/kernel/debug/tracing/events/ext4/ext4_mark_inode_dirty/enable
#will show how apps dirty inodes (they will be written to disk
eventually). ATTENTION: redirect output to file in tmpfs instead of
watching it in terminal (because terminal writes to pipe inode or socket
when it outputs to the screen thus dirtying it and will just flood your
output).
echo 1 >
/sys/kernel/debug/tracing/events/ext4/ext4_sync_file_enter/enable
#try to look if some application uses fsync aggressively thus making
system to immediately write data to disk.
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You received this bug notification because you are a member of Ubuntu
Bugs, which is subscribed to Ubuntu.
https://bugs.launchpad.net/bugs/607560
Title:
jbd2 writing block every 5 - 10 seconds, preventing disk spin-down and
making noise
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https://bugs.launchpad.net/ubuntu/+source/linux/+bug/607560/+subscriptions
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