Re: [PATCH] rudimentary tracing for Classic RCU

From: Frédéric Weisbecker
Date: Thu Oct 09 2008 - 06:23:25 EST


2008/10/9 Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>:
> Hello!
>
> This is a tracing patch for Classic RCU, which creates an "rcu/rcucb"
> file in debugfs. This patch can be handy when you need to work out
> why RCU is refusing to end the current grace period.
>
> Reading from the file results in something like the following:
>
> rcu: cur=1129 completed=1128 np=0 s=0
> 0,3,7
> rcu_bh: cur=-287 completed=-287 np=0 s=0
>
> online: 0-7


Hi Paul,

Why don't you use the ring-buffer tracing engine?
You will really make your life better by putting it as a tracer in
kernel/trace and by using the relevant API.
That will avoid you to manage the debugfs things, the memory
allocation, the buffer managment.....
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