ureadahead should have config option to disable or force ssd/hdd mode
Bug #577763 reported by
Sitsofe Wheeler
This bug affects 9 people
Affects | Status | Importance | Assigned to | Milestone | |
---|---|---|---|---|---|
ureadahead (Ubuntu) |
Triaged
|
Wishlist
|
Unassigned |
Bug Description
Some cheap/old SSDs fail to report their non rotational nature to the kernel. This results in ureadahead treating them as a rotational disk, which can actually cause slower boot times than not using ureadahead at all. There should be a config option to allow affected users to correct this by either forcing ureadahead to ssd mode, or disabling it entirely. Preferably this should be in /etc/default and/or configurable via debconf so a simple dpkg-reconfigure will suffice.
Changed in ureadahead (Ubuntu): | |
importance: | Medium → Wishlist |
status: | New → Triaged |
summary: |
- ureadahead slows down boot on cheap SSDs (e.g. EeePC 900 SSD) + ureadahead should have config option to disable or force ssd/hdd mode |
description: | updated |
To post a comment you must log in.
I've done some testing and the results are shown in the attached bootcharts.
To disable ureadahead I modified /etc/init/ ureadahead. conf so that
exec /sbin/ureadahead --daemon
was changed to
#exec /sbin/ureadahead --daemon
(this applies to bootcharts 1, 4 and 10). This was reversed to re-enable it for other steps.
Before bootchart 5 I modified /etc/init/ ureadahead. conf so that
start on starting mountall
was changed to
start on started udev
. This changed remained for all later bootcharts.
Before bootchart 8 I added the attachment 10-ssd.rules to /etc/udev/rules.d/ . This change remained for all later boot charts.
Here's a summary of times and the settings used to make the bootcharts:
1 - Time 25.57. Boot with disabled readahead.
2 - Time 25.68. Boot performing profiling. ureadahead.conf is starting mountall. Pack generated is pack-rotational-1 .
3 - Time 27.57. Boot with readahead.
4 - Time 27.01. Boot with disabled readahead.
5 - Time 27.35. Boot with readahead. ureadahead.conf modified to started udev . (Pack used is pack-rotational-1 as made in 2)
6 - Time 25.68. Boot performing profiling. Pack generated is pack-rotational-2 .
7 - Time 27.25. Boot with readahead.
8 - Time 25.57. Boot performing profiling. 10-ssd.rules added to /etc/udev/rules.d/. Pack generated is pack-ssd-1 .
9 - Time 24.47. Boot with readahead.
10 - Time 25.51. Boot with disabled readahead.