kded re-reads files every second

[Christian Iversen]

It seems that an instance of the KDE Daemon, kded, re-reads certain files
every second. This leads to wasted CPU time, and less chance of
power saving on laptops.

The following is a piece of an strace, which demonstrates the cycle:

fstat64(11, {st_mode=S_IFREG|0600, st_size=7558, ...}) = 0
munmap(0xb6033000, 7558) = 0
rt_sigaction(SIGBUS, {SIG_DFL}, NULL, 8) = 0
close(11) = 0
stat64("/home/chrivers/.kde/share/config/kcmlaptoprc", {st_mode=S_IFREG|0600, st_size=1692, ...}) = 0
stat64("/etc/kde3/kcmlaptoprc", 0xbff493f8) = -1 ENOENT (No such file or directory)
stat64("/usr/share/kubuntu-default-settings/kde-profile/default/share/config/kcmlaptoprc", {st_mode=S_IFREG|0644, st_size=520, ...}) = 0
open("/usr/share/kubuntu-default-settings/kde-profile/default/share/config/kcmlaptoprc", O_RDONLY|O_LARGEFILE) = 11
fstat64(11, {st_mode=S_IFREG|0644, st_size=520, ...}) = 0
fstat64(11, {st_mode=S_IFREG|0644, st_size=520, ...}) = 0
mmap2(NULL, 520, PROT_READ, MAP_PRIVATE, 11, 0) = 0xb6034000
fstat64(11, {st_mode=S_IFREG|0644, st_size=520, ...}) = 0
rt_sigaction(SIGBUS, {0xb7839090, [], SA_ONESHOT}, {SIG_DFL}, 8) = 0
rt_sigprocmask(SIG_BLOCK, NULL, [], 8) = 0
fstat64(11, {st_mode=S_IFREG|0644, st_size=520, ...}) = 0
munmap(0xb6034000, 520) = 0
rt_sigaction(SIGBUS, {SIG_DFL}, NULL, 8) = 0
close(11) = 0
open("/home/chrivers/.kde/share/config/kcmlaptoprc", O_RDONLY|O_LARGEFILE) = 11
fstat64(11, {st_mode=S_IFREG|0600, st_size=1692, ...}) = 0
fstat64(11, {st_mode=S_IFREG|0600, st_size=1692, ...}) = 0
mmap2(NULL, 1692, PROT_READ, MAP_PRIVATE, 11, 0) = 0xb6034000
fstat64(11, {st_mode=S_IFREG|0600, st_size=1692, ...}) = 0
rt_sigaction(SIGBUS, {0xb7839090, [], SA_ONESHOT}, {SIG_DFL}, 8) = 0
rt_sigprocmask(SIG_BLOCK, NULL, [], 8) = 0
fstat64(11, {st_mode=S_IFREG|0600, st_size=1692, ...}) = 0
munmap(0xb6034000, 1692) = 0
rt_sigaction(SIGBUS, {SIG_DFL}, NULL, 8) = 0

After approximately these many system calls, the exact same set
of calls are performed again, this re-reading the file. On a top(1),
it's clearly visible that the kded uses a lot of time:

 5660 chrivers 15 0 41184 6400 4540 S 0.7 0.6 20:21.07 kded

Only kcryptd and xorg uses more than kded here!

[Ralph Janke (txwikinger)]

Thank you for taking the time to report this bug and helping to make Ubuntu better. This bug did not have a package associated with it, which is important for ensuring that it gets looked at by the proper developers. You can learn more about finding the right package at [WWW] https://wiki.ubuntu.com/Bugs/FindRightPackage. I have classified this bug as a bug in kdelibs.

[Jonathan Thomas (echidnaman)]

Thank you for taking the time to report this bug and helping to make Ubuntu better. You reported this bug a while ago and there hasn't been any activity in it recently. We were wondering if this is still an issue for you. Can you try with the latest Ubuntu release? Thanks in advance.

[Jonathan Thomas (echidnaman)]

We are closing this bug report because it lacks the information we need to investigate the problem, as described in the previous comments. Please reopen it if you can give us the missing information, and don't hesitate to submit bug reports in the future. To reopen the bug report you can click on the current status, under the Status column, and change the Status back to "New". Thanks again!