kern/73245: 'swap-in' causes several second hesitation on mouse and keyboard input

[bob frazier]

>Number:         73245
>Category:       kern
>Synopsis:       'swap-in' causes several second hesitation on mouse and keyboard input
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    freebsd-bugs
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Thu Oct 28 16:20:25 GMT 2004
>Closed-Date:
>Last-Modified:
>Originator:     bob frazier
>Release:        FreeBSD 5.3-STABLE #0
>Organization:
SFT Inc.
>Environment:
FreeBSD beater.SFT.local 5.3-STABLE FreeBSD 5.3-STABLE #0: Thu Oct 21 12:05:12 PDT 2004     root at beater.SFT.local:/usr/obj/usr/src/sys/GENERIC  i386

>Description:
when an inactive process 'swaps out', several seconds can pass before the process will accept any input again if the process is re-activated.  This primarily takes place while xorg is running, though it is not restricted to xorg.  Even 'sysmouse' can stall if there is no mouse motion for an extended period of time, such that moving the mouse does not cause the mouse pointer to move at ALL for several seconds.  Typically it shows up in applications running in the background, such as 'xterm', where switching focus to them in 'X' via the mouse or ALT+TAB (or using ALT+Fx or CTRL+ALT+Fx to switch to another console, INCLUDING a logged out console) and then immediately typing does not echo the keys typed for several seconds.
>How-To-Repeat:
a) run a gnome 2 session in xorg
b) open several applications (web browser, xterm sessions, e-mail, xchat, and so on).
c) use one of the applications for an extended period of time.  Leaving 'xchat' going in an active channel for 30 minutes should be sufficient.
d) use one of the normal methods (mouse motion, ALT+TAB, CTRL+ALT+Fx) to switch to a virtual console or a different application.  Type text in immediately.  Observe that in many cases, a delay occurs before the keys echo.

>Fix:
If you periodically 'activate' an application, the delay doesn't happen.  It only seems to happen when an application (including a logged off console) is not activated for a significant period of time.
>Release-Note:
>Audit-Trail:
>Unformatted: