gnome-settings-daemon opens /usr/share/zoneinfo/* every 30 seconds or so

[Colin Ian King]

I've been trying to figure out why my HDD keeps on flushing metadata out every minute on an idle laptop and discovered that gsd-color opens /usr/share/zoneinfo/Europe/London on my machine at regular intervals. This causes the access time (atime) to be updated causing a metadata flush afterwards. On an idle laptop this makes the HDD spin up, write data and then spin down again. This consumes power.

Can this periodic open/closing be fixed or at least try to use O_NOATIME on the opening to reduce the metadata atime updates?

I diagnosed this by running:

sudo fnotifystat -v -x/sys,/proc,/home

one can see that the gsd-color is opening and closing the file.

Looking deeper, I used health-check on gsd-color to gather the attached activity log of 5 minutes of activity of gsd-color on the idle machine.

To capture the activity I used:

sudo health-check -p gsd-color -d 300 -f -r -v > gnome-gsd-color-5min.log

I'm pretty sure that opening the zoneinfo file with O_NOATIME will avoid the metadata atime flushes and because the data has not changed on disk it should avoid the HDD spinup/spindown cycling. Alternatively, can the regular zoneinfo reads be avoided to save power?

This seems like an identical bug as: https://launchpad.net/bugs/1846768