On Thu, Oct 21, 2010 at 07:20:27AM +0200, Christoph Hellwig wrote: > On Tue, Oct 19, 2010 at 03:29:51PM +0100, Richard W.M. Jones wrote: > > On Tue, Oct 19, 2010 at 03:59:36PM +0200, Jan Kiszka wrote: > > > Once we have "-trace events=...", defining the list of active > > > tracepoints before starting qemu will be trivial (e.g. via a config > > > file). Of course, this requires that all tracepoints are built-in... > > > > Sorry that I've not been following this very closely, but does this > > sort of thing allow tracing reads and writes to block devices? Am I > > right in thinking that if a tracepoint existed in the right place, one > > could get a log file from that which could be post-processed in > > another tool? > > I don't think it does. But I have a patch that I need to update which > outputs traces in the form of the Linux blktrace block I/O tracing tool, > which does exactly what you need (and more). You can simply use > all the blktrace-enabled tools, including seekwatcher on it.
It's on the to-do list to use blktrace instead, so a patch which changed qemu to produce blktrace-like output would be useful. Rich. -- Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones virt-df lists disk usage of guests without needing to install any software inside the virtual machine. Supports Linux and Windows. http://et.redhat.com/~rjones/virt-df/
