Re: [PATCH RFC v2 3/3] drivers: irqchip: pdc: log PDC info in FTRACE

[Lina Iyer]

On Fri, Feb 02 2018 at 23:02 +0000, Lina Iyer wrote:
> On Fri, Feb 02 2018 at 15:57 +0000, Thomas Gleixner wrote:
> > On Fri, 2 Feb 2018, Lina Iyer wrote:
> > > +++ b/include/trace/events/pdc.h
> > > @@ -0,0 +1,55 @@
> > > +/* Copyright (c) 2017-2018, The Linux Foundation. All rights reserved.
> > > + *
> > > + * This program is free software; you can redistribute it and/or modify
> > > + * it under the terms of the GNU General Public License version 2 and
> > > + * only version 2 as published by the Free Software Foundation.
> > > + *
> > > + * This program is distributed in the hope that it will be useful,
> > > + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> > > + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> > > + * GNU General Public License for more details.
> >
> > Can you please use the proper SPDX identifiers instead of the boiler plate?
> > Same for the driver source file.
> Sure.
>
> > > + */
> > > +
> > > +#undef TRACE_SYSTEM
> > > +#define TRACE_SYSTEM pdc
> > > +
> > > +#if !defined(_TRACE_PDC_) || defined(TRACE_HEADER_MULTI_READ)
> > > +#define _TRACE_PDC_H_
> > > +
> > > +#include <linux/tracepoint.h>
> > > +
> > > +#define PDC_ENTRY		1
> > > +#define PDC_TYPE_CONFIG		2
> > > +
> > > +TRACE_EVENT(irq_pin_config,
> >
> > This is really a too generic name for a PDC specific breakpoint.
> Hmm.. right.
>
> > Aside of that the question is whether this really justifies a trace
> > point. Wouldn't it be sufficient to use the GENERIC_IRQ_DEBUGFS
> > infrastructure to make this accessible via debugfs?
> Some product configurations disable debugfs. I will ask around if this
> can be dropped.
Memory dumps after a crash have support for FTRACE and it helps greatly
on production issues. Hence the preference for FTRACE support.

-- Lina