Stefan Hajnoczi <stefa...@linux.vnet.ibm.com> wrote: > On Mon, Nov 29, 2010 at 08:00:18PM -0600, Anthony Liguori wrote: >> Yeah, all of this should be done via tracing. Maybe Stefan can make >> some suggestions. > > Here is an example of how to record savevm timestamps using tracing. > Actually the timestamp is recorded automatically when a trace event > fires. > > Add these to the trace-events file: > savevm_start(void) "" > savevm_stop(unsigned int section_id) "section_id %u" > > Then use trace_savevm_start() instead of START_SAVEVM_CLOCK() and > trace_savevm_stop() instead of STOP_SAVEVM_CLOCK() in savevm.c. Also > #include "trace.h". > > All the macros and inline timestamp analysis can be removed from > savevm.c. > > ./configure --trace-backend=simple [...] > make > > After running savevm look for the trace-<pid> file that QEMU produces in > its current working directory. You can pretty-print it like this: > ./simpletrace.py trace-events trace-<pid> > > The second field in the simpletrace.py output is the time delta (in > microseconds) since the last trace event. So you can easily see how > long start->stop took. > > For more info see docs/tracing.txt. You might prefer to use SystemTap > (./configure --trace-backend=dtrace) so you can write stap scripts to do > more powerful analysis.
Thanks. Searching for guru, I basically want to only print the values when the difference is bigger that some values (number of calls is really big, I need to learn how to script the analisys). But clearly this "have to be" easier than change printf's and ifs and rerun the test. Later, Juan. > Stefan
