[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] RE: qemu-dm cpu utilization
Anthony, >If you delete the timer (and set vs->timer = NULL) in >vnc_client_io_error(), does it reduce the usage? setting vs->timer=NULL causes qemu-dm to segfault when I launch vncviewer to view the virtual host. Here is a snippet of the strace results: ioctl(13, EVIOCGKEYCODE, 0x7fffff904ee0) = 0 select(17, [6 9 11 13 16], [], [], {0, 10000}) = 1 (in [13], left {0, 10000}) read(13, "\34\0\0\0", 4) = 4 write(13, "\34\0\0\0", 4) = 4 clock_gettime(CLOCK_MONOTONIC, {87584, 18585008}) = 0 clock_gettime(CLOCK_MONOTONIC, {87584, 18684008}) = 0 clock_gettime(CLOCK_MONOTONIC, {87584, 18783008}) = 0 ioctl(13, EVIOCGKEYCODE, 0x7fffff904ee0) = 0 select(17, [6 9 11 13 16], [], [], {0, 10000}) = 1 (in [13], left {0, 10000}) read(13, "\34\0\0\0", 4) = 4 write(13, "\34\0\0\0", 4) = 4 clock_gettime(CLOCK_MONOTONIC, {87584, 31583008}) = 0 clock_gettime(CLOCK_MONOTONIC, {87584, 31685008}) = 0 clock_gettime(CLOCK_MONOTONIC, {87584, 31785008}) = 0 clock_gettime(CLOCK_MONOTONIC, {87584, 57104008}) = 0 --- SIGSEGV (Segmentation fault) @ 0 (0) --- Process 17185 detached According to strace, the timers account for a lot of qemu-dm's activity. Is this polling a bit excessive? Tommie McAfee Xen-Testing -----Original Message----- From: Anthony Liguori [mailto:anthony@xxxxxxxxxxxxx] Sent: Tue 8/29/2006 7:43 PM To: McAfee, Tommie M Subject: Re: qemu-dm cpu utilization McAfee, Tommie M wrote: > Using an 8-way ES7000 with 32GB of ram, I'm running xen at changset 11217 > with dom0_mem=3092M as a kernel parameter on a x86_64 hyperviser. > > It appears that qemu is adding too much overhead to > virtual machines to display graphics. > If I boot a sles9sp3 domVT in runlevel 5 with vga=0x314 for a graphicalboot, > and immediately use > vncviewer simply to watch the virtual machine as it boots, > qemu-dm consumes 40% cpu as soon as vncviewer is launched and remains that > way throughout this entire process without settling down when the login > screen appears. > Even If I close the console that's viewing the virtual host, qemu-dm remains > at 40-44%. Almost everything in the VNC code resets when a guest disconnected except for the timer. If a client disconnects, the timer routine should be almost a nop but it's possible that it's somehow causing qemu-dm to do something funky. If you delete the timer (and set vs->timer = NULL) in vnc_client_io_error(), does it reduce the usage? BTW, if you're using 800x600, I suspect that you may be falling back to MMIO instead of a linear framebuffer. Try moving to 1024x768 and see if that helps. Regards, Anthony Liguori > > When booting the same domVT in runlevel 5 without ever attempting to connect > to it with > vncviewer, qemu-dm fluctuated from 1-3% while the host was booting and then > settled to 0.2% after 4-5 mins. Assuming that the boot process was complete, > I launched vncviewer and qemu-dm jumped up to a 40-44% range again. > > Lastly I started the same host in runlevel 3 in pure text mode without any > vga parameters on the kernel line, connected to the virtual machine with > vncviewer, and watched the machine boot until a login prompt appeared. At > this point, top showed qemu-dm as using 0% of the cpu. Logging into the > virtual machine and running 'startx' however sent qemu-dm back up to a 40- > 44% range. > > Why is qemu-dm consuming so much of the cpu? Why is qemu-dm still high > even when I close my vncviewer? > > Tommie, > Xen Test Team > Unisys > > > > ------------------------------------------------------------------------ > > _______________________________________________ > Xen-devel mailing list > Xen-devel@xxxxxxxxxxxxxxxxxxx > http://lists.xensource.com/xen-devel _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxxxxxxxx http://lists.xensource.com/xen-devel
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