e4rat - reduce boot time (into X) by some 50% for ext4

Stunts · 2011-04-14 10:31:38

The difference between readahead +/- preload is probably just error from the stopwatch. preload never seemed to make much difference for me anyway... But I thought I'd include it here for comparison's sake.
Just to be sure, if I ever want to "reprofile" e4rat I should just make the whole procedure from the start right? Since Gnome3 will be hitting [extra] soon I think it will probably be useful to reprofile e4rat after G3 is installed.

toad · 2011-04-14 10:33:51

Yep, you need to collect the new data, reallocate it and Bob's your proverbial uncle. No need to fart around with grub kernel line any more.

ttux · 2011-04-14 17:48:52

I have a problem getting it to work. I have the following in my kernel line:
kernel /boot/linux-2.6.38-2 root=/dev/sda4 rw quiet acpi_enforce_resources=lax init=/sbin/e4rat-collect

It says it will collect for 120 sec. I can see the process running before it stops after 120 sec but unfortunately it doesn't create a startup.log file so I cannot do the next steps.

I have only one partition /
/dev/sda4 / ext4 defaults 0 1

As I can't see any error message about what's wrong, is there a way I could get more logs / debugging? Or maybe you have an idea about what I am doing wrong?

toad · 2011-04-14 19:25:14

@ ttux

Hm, you got auditd in your rc.conf? If so, disable it.

ttux · 2011-04-14 19:31:18

toad wrote:

@ ttux
Hm, you got auditd in your rc.conf? If so, disable it.

I don't have auditd in my rc.conf

toad · 2011-04-14 19:48:27

@ ttux

Out of ideas at the mo. What do your logs say (standard question, I know) - cat /var/log/*|grep e4rat might give us some idea.

@ graysky

We have a new version 0.2.1 to take account of e4rat's first bug report

taugenix · 2011-04-14 19:49:52

ttux wrote:

I have a problem getting it to work. I have the following in my kernel line:
kernel /boot/linux-2.6.38-2 root=/dev/sda4 rw quiet acpi_enforce_resources=lax init=/sbin/e4rat-collect
It says it will collect for 120 sec. I can see the process running before it stops after 120 sec but unfortunately it doesn't create a startup.log file so I cannot do the next steps.
I have only one partition /
/dev/sda4 / ext4 defaults 0 1
As I can't see any error message about what's wrong, is there a way I could get more logs / debugging? Or maybe you have an idea about what I am doing wrong?

hi ttux,

to get log messages run `dmesg | grep e4rat '
If it doesn't help increate the loglevel in /etc/e4rat.conf

ttux · 2011-04-14 20:01:20

dmesg | grep e4rat
Command line: root=/dev/sda4 ro quiet acpi_enforce_resources=lax init=/sbin/e4rat-collect
Kernel command line: root=/dev/sda4 ro quiet acpi_enforce_resources=lax init=/sbin/e4rat-collect

ttux · 2011-04-14 20:12:44

Ok sorry for having bothered you. I changed verbose and loglevel to 31 and it says my filesystem is ext2... Although in my head I was sure I had ext4 + I have ext4 in fstab. My install is quite old so I don't remember what I've done when I did it...

toad · 2011-04-14 20:13:24

sonay · 2011-04-14 21:54:23

I don't know where to report this bug, but I should warn you. It's not playing nice with filenames containing spaces. Don't worry though, it just complains about syntax when reallocating. No data lost, at least not in my hard drive.

graysky · 2011-04-14 23:45:34

sonay wrote:

I don't know where to report this bug, but I should warn you. It's not playing nice with filenames containing spaces. Don't worry though, it just complains about syntax when reallocating. No data lost, at least not in my hard drive.

Why do you have spaces in your files names

fsckd · 2011-04-15 01:08:17

What kind of spaces are we talking about?

Viper_Scull · 2011-04-15 11:25:48

toad wrote:

@ triplesquarednine
No news on systemd - I cannot remember whether anybody in this thread has tried it. Other than that there is no further info out there.

I use systemd so i could try, but since i'm on an SSD i think it'd be worthless.

Awesome application though.

toad · 2011-04-15 11:42:28

e4rat does not have a bug report system (yet). Afaik it is only this community using it. Once it starts in other communities (read Debian) the user base is likely to grow and a bug reporting system would be cool. Anybody here who knows their way round sourceforge? Do they provide a tool? In the meantime please use the email address stated on the project page

@ Viper_Scull
That would be very helpful, especially if you contributed to the wiki or report your findings in such a way that I can incorporate them. But you are right, it is highly unlikely that you get any performance gain with an SSD.

toad · 2011-04-15 11:53:33

Somebody named Plco put the following in the wiki:

Caveat emptor: the current version of e4rat (0.20) will severely damage any partition that has been converted to ext4. This is likely because existing files are not converted to use extents, and e4rat has no built-in mechanism to detect this condition. Before using e4rat you should backup the affected partitions, reformat them as ext4 and then restore the backups. Given the current status and the nature of the program, it's a smart move to backup the system before attempting reallocation anyway.

Any comments?

fsss · 2011-04-15 12:11:41

I'm using e4rat with systemd. This combination works properly, though Arch is booting slower than with standard init. I have no idea why. Without e4rat systemd loads system slightly faster than init. I didn't generate any charts so far, but I will.

graysky · 2011-04-15 21:07:04

toad wrote:

Somebody named Plco put the following in the wiki:
Caveat emptor: the current version of e4rat (0.20) will severely damage any partition that has been converted to ext4. This is likely because existing files are not converted to use extents, and e4rat has no built-in mechanism to detect this condition. Before using e4rat you should backup the affected partitions, reformat them as ext4 and then restore the backups. Given the current status and the nature of the program, it's a smart move to backup the system before attempting reallocation anyway.
Any comments?

Email the author/bug report?

iTheKronic · 2011-04-15 22:56:40

I just installed it, and i notice a big difference at least 10 seconds shaved of the boot time!
Didn't make any boot charts though.

ttux · 2011-04-16 13:49:53

ttux wrote:

Ok sorry for having bothered you. I changed verbose and loglevel to 31 and it says my filesystem is ext2... Although in my head I was sure I had ext4 + I have ext4 in fstab. My install is quite old so I don't remember what I've done when I did it...

So I have recreated my partition with mkfs.ext4 and unfortunately I still have the message saying my filesystem is ext2...

I have in dmesg:
[e4rat-collect] Connecting to the audit socket ...
[e4rat-collect] Stop collecting files automatically after 70 seconds
[e4rat-collect] Starting event processing ...
[e4rat-collect] / is not an ext4 filesystem
[e4rat-collect] Filesystem of / is ext2

I even removed the support for ext2 and ext3 from my kernel.

/etc/mtab gives me:
/dev/root/ / ext4 rw,noatime,barrier=1,data=ordered

taugenix · 2011-04-16 15:26:11

ttux wrote:

ttux wrote:
Ok sorry for having bothered you. I changed verbose and loglevel to 31 and it says my filesystem is ext2... Although in my head I was sure I had ext4 + I have ext4 in fstab. My install is quite old so I don't remember what I've done when I did it...
So I have recreated my partition with mkfs.ext4 and unfortunately I still have the message saying my filesystem is ext2...
I have in dmesg:
[e4rat-collect] Connecting to the audit socket ...
[e4rat-collect] Stop collecting files automatically after 70 seconds
[e4rat-collect] Starting event processing ...
[e4rat-collect] / is not an ext4 filesystem
[e4rat-collect] Filesystem of / is ext2
I even removed the support for ext2 and ext3 from my kernel.
/etc/mtab gives me:
/dev/root/ / ext4 rw,noatime,barrier=1,data=ordered

Ok that sounds strange. The filesystem type is also read from /etc/mtab. It seams that your system remounts / from ext4 to ext2 during shutdown. Otherwise there is no explaination for the wrong filesystem type in /etc/mtab.
Try to set "rootfstype=ext4" to your kernel parameters and reboot one time to let the system update /etc/mtab.
Check also its content quiet after kernel has booted.

ttux · 2011-04-16 15:33:18

Ok that sounds strange. The filesystem type is also read from /etc/mtab. It seams that your system remounts / from ext4 to ext2 during shutdown. Otherwise there is no explaination for the wrong filesystem type in /etc/mtab.
Try to set "rootfstype=ext4" to your kernel parameters and reboot one time to let the system update /etc/mtab.
Check also its content quiet after kernel has booted.

mtab says it's ext4:
/dev/root/ / ext4 rw,noatime,barrier=1,data=ordered

But thanks a lot, rootfstype=ext4 does the trick and it works now

EDIT: Excellent result, from 38 sec to 18 sec! What's really different is gnome startup time (gnome3 / gnome-shell)

Last edited by ttux (2011-04-17 08:42:30)

lucak3 · 2011-04-16 17:17:45

EDITED: it seems i must check my typing many times before asking for help. sorry for the intrusion

Last edited by lucak3 (2011-04-16 17:22:59)

ChoK · 2011-04-17 10:54:12

@ttux : It might be best to have /etc/mtab as a symlink to /proc/self/mounts

btw : my bug report about e4rat relying on libraries in /usr should be fixed in 0.2.1 by the use of static libraries.

misc · 2011-04-17 12:12:51

Two questions:

1. Every relevant partition but /var (reiserfs) and another (ntfs) that holds my wallpapers, one of which gets loaded at start, has been formatted with ext4. Are these two a problem?

2. I take it that e4rat can safely be uninstalled simply by removing the "init=/sbin/e4rat-preload" part from the kernel line. Is that correct?

Also as previously mentioned, it would be great to read a sound report comparing e4rat with systemd resp. the results of their interaction, but I guess none so far exists.

Arch Linux

#101 2011-04-14 10:31:38

Re: e4rat - reduce boot time (into X) by some 50% for ext4

#102 2011-04-14 10:33:51

Re: e4rat - reduce boot time (into X) by some 50% for ext4

#103 2011-04-14 17:48:52

Re: e4rat - reduce boot time (into X) by some 50% for ext4

#104 2011-04-14 19:25:14

Re: e4rat - reduce boot time (into X) by some 50% for ext4

#105 2011-04-14 19:31:18

Re: e4rat - reduce boot time (into X) by some 50% for ext4

#106 2011-04-14 19:48:27

Re: e4rat - reduce boot time (into X) by some 50% for ext4

#107 2011-04-14 19:49:52

Re: e4rat - reduce boot time (into X) by some 50% for ext4

#108 2011-04-14 20:01:20

Re: e4rat - reduce boot time (into X) by some 50% for ext4

#109 2011-04-14 20:12:44

Re: e4rat - reduce boot time (into X) by some 50% for ext4

#110 2011-04-14 20:13:24

Re: e4rat - reduce boot time (into X) by some 50% for ext4

#111 2011-04-14 21:54:23

Re: e4rat - reduce boot time (into X) by some 50% for ext4

#112 2011-04-14 23:45:34

Re: e4rat - reduce boot time (into X) by some 50% for ext4

#113 2011-04-15 01:08:17

Re: e4rat - reduce boot time (into X) by some 50% for ext4

#114 2011-04-15 11:25:48

Re: e4rat - reduce boot time (into X) by some 50% for ext4

#115 2011-04-15 11:42:28

Re: e4rat - reduce boot time (into X) by some 50% for ext4

#116 2011-04-15 11:53:33

Re: e4rat - reduce boot time (into X) by some 50% for ext4

#117 2011-04-15 12:11:41

Re: e4rat - reduce boot time (into X) by some 50% for ext4

#118 2011-04-15 21:07:04

Re: e4rat - reduce boot time (into X) by some 50% for ext4

#119 2011-04-15 22:56:40

Re: e4rat - reduce boot time (into X) by some 50% for ext4

#120 2011-04-16 13:49:53

Re: e4rat - reduce boot time (into X) by some 50% for ext4

#121 2011-04-16 15:26:11

Re: e4rat - reduce boot time (into X) by some 50% for ext4

#122 2011-04-16 15:33:18

Re: e4rat - reduce boot time (into X) by some 50% for ext4

#123 2011-04-16 17:17:45

Re: e4rat - reduce boot time (into X) by some 50% for ext4

#124 2011-04-17 10:54:12

Re: e4rat - reduce boot time (into X) by some 50% for ext4

#125 2011-04-17 12:12:51

Re: e4rat - reduce boot time (into X) by some 50% for ext4

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