On Mon, Aug 29, 2016 at 08:46:02PM +0200, Lluís Vilanova wrote: > Stefan Hajnoczi writes: > > > When SystemTap is used the QEMU monitor interface does nothing. > > That's not what I've experienced. I was able to use a stap script to change > the > tracing state of events: > > #!/usr/bin/env stap > > %{ > #include </home/lluis/Projects/qemu-dbi-test/test.h> > %} > > function event:long(cpu:long, addr:long, info:long) > %{ > char *argv[4] = {"/bin/sh", "-c", "echo 'trace-event * off' | telnet > localhost 1234", NULL}; > call_usermodehelper(argv[0], argv, NULL, UMH_WAIT_EXEC); > STAP_RETURN(0); > %}
I don't know what you're trying to achieve here. The trace-event state, as changed/viewed via QEMU monitor, is irrelevant to the dtrace (systemtap) backend. dtrace and ltt-ust are both fully dynamic trace event backends, so the QEMU event state has no effect on them. The probe points in the binary are dynamically enabled / disabled by the dtrace runtime. ie dtrace will automatically enable an event if you write a dtrace script that uses the event. Regards, Daniel -- |: http://berrange.com -o- http://www.flickr.com/photos/dberrange/ :| |: http://libvirt.org -o- http://virt-manager.org :| |: http://autobuild.org -o- http://search.cpan.org/~danberr/ :| |: http://entangle-photo.org -o- http://live.gnome.org/gtk-vnc :| _______________________________________________ lttng-dev mailing list lttng-dev@lists.lttng.org https://lists.lttng.org/cgi-bin/mailman/listinfo/lttng-dev