* Francis Giraldeau ([email protected]) wrote: > Le 2012-07-03 13:39, Mathieu Desnoyers a écrit : > > * Francis Giraldeau ([email protected]) wrote: > >> Le 2012-07-03 00:23, Mathieu Desnoyers a écrit : > >>> * Francis Giraldeau ([email protected]) wrote: > >>>> By writing to the file /proc/lttng_uevent, a user-space application > >>>> creates a > >>>> kernel event. The event's payload is by default UTF-8 text, but any data > >>>> can be > >>>> written, up to 1024 bytes. Null-character is optional and is not > >>>> enforced. > >>> > >>> The 1024 byte limit is removed now, right ? > >> > >> Exactly. > > > > OK, please provide an updated version with the updated changelog. > > Fixed. > > > > >> > >>>> + * Expose kernel tracer to user-space through /proc/lttng > >> > >> I just saw a typo here, we should read "through /proc/lttng_uevent" > > > > Same here. > > Fixed. > > > > >> > >>>> + * Copyright (C) 2009-2012 Mathieu Desnoyers > >>>> <[email protected]> > >>> > >>> you might want to add your own copyright in here too. > >> > >> I transfer you the copyright. > > > > Thanks! > > > > One more thing: > > > > In the testing you did, did you try running, in parallel: > > > > for a in $(seq 1 10000); do > > modprobe nameofuevent_module > > rmmod nameofevent_module > > done > > > > and in 4 another terminals: > > > > echo "blahblahblah" > /proc/lttng_uevent > > > > ? > > > > I understand that you tested only the write path in parallel, but I'm > > not sure, from your changelog, that you stress-tested load/unload vs > > write. > > The test I did was to write in parallel to /proc/lttng_uevent and see > the behavior. It takes about 15us on my i5 2.5Ghz to log an event this > way in a tight loop, so yeah, it's quite slow.
Yep, that's benchmarking. I'm more concerned about correctness. > It's not possible to remove the module while an active tracing session > references the event lttng_uevent. I tested insertion/removal of the > module while tracing with the previous version that was using RCU and it > was working well. But you don't need to have an active tracing session to perform the test I point to above. Could you run it on this latest version ? Thanks, Mathieu > > Cheers, > > Francis > > _______________________________________________ > lttng-dev mailing list > [email protected] > http://lists.lttng.org/cgi-bin/mailman/listinfo/lttng-dev -- Mathieu Desnoyers Operating System Efficiency R&D Consultant EfficiOS Inc. http://www.efficios.com _______________________________________________ lttng-dev mailing list [email protected] http://lists.lttng.org/cgi-bin/mailman/listinfo/lttng-dev
