From mboxrd@z Thu Jan 1 00:00:00 1970 From: tom.deneau@amd.com (Deneau, Tom) Date: Wed, 31 May 2017 23:28:45 +0000 Subject: [lttng-dev] lttng-track on userspace channel Message-ID: I am using lttng 2.9.4. I have a server database daemon with many threads and I would like to track events on a smaller subset of those threads. I noticed that on the kernel channel I can use lttng track --pid=123,124,125 and this will trace kernel events for just those TIDS (in spite of the documentation saying it will track whole pids). But I am happy because tid tracking is what I want. However, is there an equivalent way to track certain tids on the userspace channel? I find that if I use lttng track -u --pid=xxx it just tracks all the tids under that pid. Here is my script (where 79653 is a single tid). In this case it traces only kernel events on that tid. ----------- lttng create lttng enable-channel u -u --num-subbuf 64 --subbuf-size 512k lttng enable-channel k -k --num-subbuf 64 --subbuf-size 512k lttng add-context -k -c k -t tid -t pid lttng add-context -u -c u -t vtid -t vpid lttng enable-event -u -c u -a lttng enable-event -k -c k --syscall futex lttng track -k --pid=79653 lttng track -u --pid=79653 lttng start sleep 1.0 lttng stop lttng destroy -- Tom Deneau