On Fri, 23 Jul 2021 12:35:09 +0200 Stefan Metzmacher <metze@xxxxxxxxx> wrote: > > Assuming this does fix your issue, I sent out a real patch with the > > explanation of what happened in the change log, so that you can see why > > that change was your issue. > > Yes, it does the trick, thanks very much! Can I get a "Tested-by" from you? > Now I can finally use: > > trace-cmd record -e all -P $(pidof io_uring-cp-forever) > > But that doesn't include the iou-wrk-* threads > and the '-c' option seems to only work with forking. Have you tried it? It should work for threads as well. It hooks to the sched_process_fork tracepoint, which should be triggered even when a new thread is created. Or do you mean that you want that process and all its threads too that are already running? I could probably have it try to add it via the /proc file system in that case. Can you start the task via trace-cmd? trace-cmd record -e all -F -c io_uring-cp-forever ... > > Is there a way to specify "trace *all* threads of the given pid"? > (Note the threads are comming and going, so it's not possible to > specifiy -P more than once) Right, although, you could append tasks manually to the set_event_pid file from another terminal after starting trace-cmd. Once a pid is added to that file, all children it makes will also be added. That could be a work around until we have trace-cmd do it. Care to write a bugzilla report for this feature? https://bugzilla.kernel.org/buglist.cgi?component=Trace-cmd%2FKernelshark&list_id=1088173 -- Steve
