Hi, 2017-10-11 17:10 GMT-04:00 avkumar <[email protected]>: > > Perf probes: > How can we add the dynamic trace points created by perf probe into lttng? > When I add the perf probe as kprobe type I get missing tracepoint error, If I > add the perf probe as tracepoint , Lttng does not complain but it does not > collect any data when the tracepoint is hit. > > perf probe -l > probe:tcp_gro (on tcp_gro_receive@net/ipv4/tcp_offload.c with addr > len) > > lttng enable-event -k --probe=tcp_gro
First, you have to give your probe event a name. Second, tcp_gro has to be a kernel symbol. According to the Perf output above, the symbol name is `tcp_gro_receive` so the command you want to run is: lttng enable-event -k --probe=tcp_gro_receive EVENT_NAME > Error: Missing event name(s). > > When I add it as a trace point > > lttng enable-event -k probe:tcp_gro > Kernel event probe:tcp_gro created in channel channel0] > > it does not give any error but no data is collected It's expected if you don't have a kernel tracepoint named "probe:tcp_gro"(you probably don't) currently loaded in your kernel. There is no error because there is no way for the kernel tracer if the tracepoint is part of an not-yet-loaded kernel module or not. "probe:tcp_gro" is a Perf specific description of the kprobe you enabled. You can not directly reuse this description in the lttng-enable-event command. To use the `lttng enable-event -k TRACEPOINT`, try the `lttng list -k` command (with a lttng-sessiond running as root) to list the currently available tracepoints. > > > > Module tracepoints: > I created module tracepoints in the kernel and compiled the trace points. The > header file is in the driver module directory. When I write the adaptation > layer for lttng, it does not compile as it is not able to fien the header > file. I have given fill path name to the header file and still it does not > work. Can you give us a bit more details. Could you send us a pastebin of the error you get? Thank you, Francis > > > Thanks > > > > > > _______________________________________________ > lttng-dev mailing list > [email protected] > https://lists.lttng.org/cgi-bin/mailman/listinfo/lttng-dev > -- Francis Deslauriers Software developer EfficiOS inc. _______________________________________________ lttng-dev mailing list [email protected] https://lists.lttng.org/cgi-bin/mailman/listinfo/lttng-dev
