[systemd-devel] readahead-replay seems to not be doing anything.

[Gary van der Merwe]

Hi all.

This is my first post to this list, so I just want to say I thank you
too all those
who wrote systemd.

systemd-readahead-replay does not seem to be doing what it should.

Bootchart with readahead-[replay|collect] enabled:
  http://www.garyvdm.co.za/bootchart-20130211-1328.svg

Output of `/usr/lib/systemd/systemd-readahead analyze /.readahead` :
  http://www.garyvdm.co.za/systemd-readahead-analyze

There is no output in `journalctl -u systemd-readahead-replay.service`

Bootchart with readahead-[replay|collect] disabled:
  http://www.garyvdm.co.za/bootchart-20130211-1409.svg

Note that both my root & home partitions are btrfs with
options=defaults,noatime,compress=lzo.

If you compare the bootcharts, you see that there is very little io reads when
systemd-readahead-replay starts. (Do systemd-readahead-replay reads not show in
bootcharts by design?)

Am I correct in thinking that systemd-readahead-replay is not doing what it
should?

How can I debug why it is not working?



Thanks,

Gary