On Thu, Mar 29, 2012 at 5:00 PM, Julien Desfossez <[email protected]> wrote: > On 27/03/12 06:10 AM, Stefan Hajnoczi wrote: >> On Mon, Mar 26, 2012 at 1:27 PM, Julien Desfossez >> <[email protected]> wrote: >>> - indexes are sent over the control data connection >> >> What exactly is an index? I guess it's a lookup data structure that >> tells you where in the trace data to start reading? >> >> Sorry if this is outside the scope of network streaming, maybe this is >> basic Babeltrace/CTF background knowledge that I missed. > > Indeed the index is a concept in babeltrace, I should have mentionned it. > When you open a trace with Babeltrace (or with the API), before printing > the trace it generates an index in memory in order to have a mapping > between the trace packets and their position in the trace files. > > I hope it makes this proposal clearer.
Thanks, I think I understand the general scheme and it makes sense. I guess the tricky part is buffering - whether to send a tiny packet per trace event (useful in case machine A crashes) or to buffer up several packets to reduce CPU and network consumption. When machine A isn't going to crash buffering is nice, but when machine A crashes buffering is bad :). With Linux in particular it might be okay - I've had good results using netconsole to capture kernel panics. Stefan _______________________________________________ lttng-dev mailing list [email protected] http://lists.lttng.org/cgi-bin/mailman/listinfo/lttng-dev
