bottom right label "Current time". Support for this type of filtering should
be added to the filter module soon.
+* Hybrid mode
+
+Starting from LTTng 0.5.105 and ltt-control 0.20, a new mode can be used :
+hybrid. It can be especially useful when studying big workloads on a long period
+of time.
+
+When using this mode, the most important, low rate control information will be
+recorded during all the trace by lttd (i.e. process creation/exit). The high
+rate information (i.e. interrupt/traps/syscall entry/exit) will be kept in a
+flight recorder buffer (now named flight-channelname_X).
+
+The following lttctl commands take an hybrid trace :
+
+Create trace channel, start lttd on normal channels, start tracing:
+lttctl -n tracename -d -l /mnt/relayfs/ltt -t /tmp/trace1 -m hybrid
+
+Stop tracing, start lttd on flight recorder channels, destroy trace channels :
+lttctl -n tracename -f -l /mnt/relayfs/ltt -t /tmp/trace1 -m hybrid
+
+
+We will need to tweak what we consider "important" medium rate events. For
+instance, thread branding events are actually considered a "high rate" event
+when it should be considered "medium rate". The same should apply for the
+state dump process enumeration.
+
+* Flight recorder mode
+
+The flight recorder mode writes data into overwritten buffers for all channels,
+including control channels, except for the facilities tracefiles.
+
+The following lttctl commands take a flight recorder trace :
+
+lttctl -n trace -c -m flight
+lttd -n -d -t /tmp/trace -c /sys/kernel/debug/ltt
+lttctl -n trace -s
+.. do stuff
+lttctl -n trace -q
+lttd -f -d -t /tmp/trace -c /sys/kernel/debug/ltt
+lttctl -m trace -r
+
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** Section 4 * Adding new instrumentations with genevent **
projects / lttv.git / blobdiff