Bug 377054

Created attachment 104288 [details]
Krunner strace.

When using the "run command" shortcut (default: alt+space), it takes ~2s for the krunner popup to show up on my machine, which is not critical but can get quite annoying.

After stracing what happens between the shortcut press and the popup, it seems the main culprit are read and blocking polls on file descriptor 5:

10:42:01.789930 read(5, "\2\0\0\0\0\0\0\0", 16) = 8
10:42:01.789967 poll([{fd=5, events=POLLIN}, {fd=7, events=POLLIN}, {fd=10, events=POLLIN}, {fd=12, events=POLLIN}, {fd=14, events=POLLIN}, {fd=15, events=POLLPRI}], 6, 467) = 1 ([{fd=5, revents=POLLIN}])
10:42:01.792028 read(5, "\1\0\0\0\0\0\0\0", 16) = 8
10:42:01.792059 poll([{fd=5, events=POLLIN}, {fd=7, events=POLLIN}, {fd=10, events=POLLIN}, {fd=12, events=POLLIN}, {fd=14, events=POLLIN}, {fd=15, events=POLLPRI}], 6, 465) = 0 (Timeout)
10:42:02.257609 read(5, 0x7ffef446f060, 16) = -1 EAGAIN (Resource temporarily unavailable)
10:42:02.257670 poll([{fd=5, events=POLLIN}, {fd=7, events=POLLIN}, {fd=10, events=POLLIN}, {fd=12, events=POLLIN}, {fd=14, events=POLLIN}, {fd=15, events=POLLPRI}], 6, 5) = 0 (Timeout)

This last timeouted poll alone blocks the process for 0.5s. Searching backwards, it seems fd 5 is an inotify watch on a theme file:

10:41:52.724462 inotify_add_watch(10, "/usr/share/icons/breeze/index.theme", IN_MODIFY|IN_ATTRIB|IN_MOVED_FROM|IN_MOVED_TO|IN_CREATE|IN_DELETE|IN_DELETE_SELF|IN_MOVE_SELF|IN_DONT_FOLLOW) = 5

This could be caused by this write that seem to invoke "RestartStyle", on what I suppose is a DBUS socket ?

10:41:52.909666 write(7, "\1\f\1\0\10\0\0\0\1\0\0\0\0\0\0\0\20\0\0\0RestartStyle"..., 72) = 72

I do realise this might not be related to krunner but to the theme engine, but my understanding stops there.

Reproducible: always.

Steps to reproduce:

1. Press "Run command" shortcut (default: alt+space).
2. Popup takes 2s to show up.

Attached the full strace, with comments when the shortcut is pressed and when the popup actually shows up.