Messages in this thread | | | Date | Wed, 18 Mar 2009 09:59:57 +0100 | From | Ingo Molnar <> | Subject | Re: [PATCH] tracing/ftrace: stop {irqs,preempt}soff tracers when tracing is stopped |
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* Frederic Weisbecker <fweisbec@gmail.com> wrote:
> On Tue, Mar 17, 2009 at 05:59:22PM -0400, Steven Rostedt wrote: > > > > On Tue, 17 Mar 2009, Frederic Weisbecker wrote: > > > > > + /* > > > > > + * Stop the tracer to avoid a warning subsequent > > > > > + * to buffer flipping failure because tracing_stop() > > > > > + * disables the tr and max buffers, making flipping impossible > > > > > + * in case of parallels max preempt off latencies. > > > > > + */ > > > > > + trace->stop(tr); > > > > > /* stop the tracing. */ > > > > > tracing_stop(); > > > > > > > > I'm actually thinking that tracing_stop() should call the current tracer > > > > "stop" function. > > > > > > > > -- Steve > > > > > > > > > Indeed, it could be better. > > > But I think of a combination of stop() callback call plus > > > ring buffer disabled because I'm not sure all tracers implement > > > the stop callback. > > > > Yes, that's what I meant. The tracing_stop should do a few things, and one > > of them is to call the stop function if it exists. > > > > > > > > Should I send a v2 based on the above? > > > > Sure. > > > > -- Steve > > > Ingo, > > I tested the call to the start/stop callbacks from tracing_start() > and tracing_stop() but it's not possible for now: the sched_switch > tracer register/unregister his tracepoints from these callbacks, > thus allocate some memory. But tracing_start/stop can be called > from atomic. > > I discussed about that with Steven on irc, and for now the v1 > should be applied as a temporary solution. We plan to simplify > later the start/stop callbacks from each tracers that need it.
ok. Steve, could you please pick v1 up?
Ingo
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