[lttng-dev] [PATCH] Expose kernel tracer to user-space (version 6)

[Mathieu Desnoyers]

* Francis Giraldeau (francis.giraldeau at gmail.com) wrote:
> Le 2012-07-03 00:23, Mathieu Desnoyers a écrit :
> > * Francis Giraldeau (francis.giraldeau at gmail.com) 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.

> 
> >> + * Expose kernel tracer to user-space through /proc/lttng
> 
> I just saw a typo here, we should read "through /proc/lttng_uevent"

Same here.

> 
> >> + * Copyright (C) 2009-2012 Mathieu Desnoyers <mathieu.desnoyers at efficios.com>
> > 
> > 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.

Thanks,

Mathieu

> 
> Thanks!
> 
> Francis
> 



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-- 
Mathieu Desnoyers
Operating System Efficiency R&D Consultant
EfficiOS Inc.
http://www.efficios.com