On Sun, Oct 31, 2010 at 3:31 AM, Ted Ts'o <tytso@xxxxxxx> wrote: > On Sat, Oct 30, 2010 at 07:02:35PM +0600, Aidar Kultayev wrote: >> the system is/was doing : >> .dd if=/dev/zero of=test.10g bs=1M count=10000;rm test.10g >> .netbeans >> .compiling gcc-4.5.1 >> .running VBox, which wasn't doing any IO. The guest os was idle in other words >> .vlc >> .chromium >> .firefox >> and bunch of other small stuff. >> >> Even without having running DD, the mouse cursor would occasionally >> lag. The alt+tab effect in KWin would take 5+seconds to workout. >> When I run DD on top of the workload it consistently made system much >> more laggy. The cursor would freeze much more frequent. It is like if >> you drag your mouse physically, but the cursor on the screen would >> jump discretely, in other words there is no continuity. >> Music would stop. > > If you start shutting down tasks, Vbox, netbeans, chromium, etc., at > what point does the cursor start tracking the system easily? ÂIs the > system swapping? ÂDo you know how to use tools like dstat or iostat to > see if the system is actively writing to the swap partition? Â(And are > you using a swap partition or a swap file?) > > The fact that cursor isn't tracking well even when the dd is running, > and presumably the only source of I/O is the gcc and vlc, makes me > suspect that you may be swapping pretty heavily. ÂHave you tried > investigating that possibility, and made sure it has been ruled out? Something to try is also to raise X cpu scheduling priority, since I would be really surprised if we evict from memory the routine that draws the cursor. BTW, I've seen the cursor jumping problem even when not swapping, and with minimal *real* disk activity (but with heavy usage of a fuse filesystem providing remote resources), and high cpu activity. Raising X priority solved the problem with the mouse pointer, but the gui programs still didn't respond quickly... Thanks Corrado > > Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â- Ted > > -- > To unsubscribe, send a message with 'unsubscribe linux-mm' in > the body to majordomo@xxxxxxxxxx ÂFor more info on Linux MM, > see: http://www.linux-mm.org/ . > Fight unfair telecom policy in Canada: sign http://dissolvethecrtc.ca/ > Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a> > -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxxx For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom policy in Canada: sign http://dissolvethecrtc.ca/ Don't email: <a href