chore: enlarge buffer size for avoiding tracer discarded (ros2#2)

Signed-off-by: Takayuki AKAMINE <[email protected]>

Signed-off-by: Takayuki AKAMINE <[email protected]>

Author: takam5f2

tracetools_trace/tracetools_trace/tools/lttng_impl.py

@@ -151,10 +151,10 @@ def setup(
         channel_ust.name = channel_name_ust
         # Discard, do not overwrite
         channel_ust.attr.overwrite = 0
-        # 2 sub-buffers of 8 times the usual page size
+        # 2 sub-buffers of 32 times the usual page size
         # We use 2 sub-buffers because the number of sub-buffers is pointless in discard mode,
         # and switching between sub-buffers introduces noticeable CPU overhead
-        channel_ust.attr.subbuf_size = 8 * 4096
+        channel_ust.attr.subbuf_size = 32 * 4096
         channel_ust.attr.num_subbuf = 2
         # Ignore switch timer interval and use read timer instead
         channel_ust.attr.switch_timer_interval = 0