Michael Wojcik wrote:
Paul A. Rubin wrote:
AFAIK, csrss manages application access to the graphics subsystem, so
I suspect that every time the GUI writes to the screen, csrss is
involved.
[This is a bit late, but it may be of use to other people who run into
this.]
csrss is the "Client/Server Runtime System Service". It's the usermode
part of the Win32 component of modern MS Windows versions.
It handles things like the userspace side of thread creation and
deletion, and console-mode I/O. (So, for example, if LyX were running
with debug enabled, the debug lines being written to the LyX console
window might cause a noticeable jump in csrss load. But I haven't
tested that.) I don't know offhand of anything it does with graphical
rendering tasks, but that doesn't mean it doesn't have its hooks in
there, too.
Also, some malware - eg some Nimda variants - which drop bogus csrss.exe
executables on the machine, so in some cases a busy csrss is actually a
trojan. Since you've confirmed the OP's problem on your own system,
though, that's not the issue here.
It's eating way too many cycles, though, and for that matter LyX
seems to be eating more than I would expect.
People have reported all sorts of triggers for excessive CPU consumption
in csrss: problems with user profiles, stopping the Windows Messenger
service, changing power management settings, bad interaction between
ProcessExplorer (which starts threads in other processes) and cygwin, a
bad TweakUI setting... Sometimes it's due to poor application coding (I
saw one report of a console app that busy-waited on the kbhit() system
call, which goes through csrss). Sometimes it's due to bugs in the OS,
as with the Messenger issue.
Because csrss is used for several common tasks, it's hard to guess just
what might be causing the problem.
One way to track the problem down would be to build LyX with symbols and
profile it using kernrate, the free Microsoft sampling profiler, to
find out where the hotspots are. Unfortunately I'm not set up to build
LyX, and I don't have time right now to pull the sources and do that.
(I'm not sure I have the disk space required, for that matter.)
Michael,
Thanks, that's very informative. I think I've seen some reports of slow
screen performance on Linux systems, but since I'm limited to Windows I
didn't pay them much attention. It's possible that's a related problem,
in which case hopefully the developers will lick it soon. If this
really is Windows only, hopefully what you posted here will help them
track down the bug. (Like you I'm not set up to build LyX, and I swore
off C++ a while back on the advice of my psychoanalyst.)
/Paul
