Re: [RFC][PATCH 1/5] [PATCH 1/5] events: Add EVENT_FS the event filesystem [LWN.net]

From:		Peter Zijlstra <peterz-AT-infradead.org>
To:		Ingo Molnar <mingo-AT-elte.hu>
Subject:		Re: [RFC][PATCH 1/5] [PATCH 1/5] events: Add EVENT_FS the event filesystem
Date:		Wed, 17 Nov 2010 16:16:49 +0100
Message-ID:		<1290007009.2109.926.camel@laptop>
Cc:		Steven Rostedt <rostedt-AT-goodmis.org>, Greg KH <gregkh-AT-suse.de>, linux-kernel-AT-vger.kernel.org, Andrew Morton <akpm-AT-linux-foundation.org>, Thomas Gleixner <tglx-AT-linutronix.de>, Frederic Weisbecker <fweisbec-AT-gmail.com>, Linus Torvalds <torvalds-AT-linux-foundation.org>, Theodore Tso <tytso-AT-mit.edu>, Arjan van de Ven <arjan-AT-infradead.org>, Mathieu Desnoyers <mathieu.desnoyers-AT-efficios.com>, Lin Ming <ming.m.lin-AT-intel.com>, Arnaldo Carvalho de Melo <acme-AT-redhat.com>
Archive-link:		Article, Thread

On Wed, 2010-11-17 at 16:03 +0100, Ingo Molnar wrote:
> I think Arjan's complaints at the KS stemmed from prior sporadic declarations on 
> lkml that there is no tracepoint ABI _at all_, and that powertop/latencytop could 
> break anytime. 

And it will, afaik Arjan refused to even parse the format file which is
part of the tracepoint abi and I'll be changing those for the scheduler.

I really object to not being able to make sane changes just because some
tool is too lazy to even implement the full ABI that was exposed.

> I think Arjan's complaints at the KS stemmed from prior sporadic declarations on 
> lkml that there is no tracepoint ABI _at all_, and that powertop/latencytop could 
> break anytime. 

I fully intent to break powertop/latencytop if they refuse to use the
format file, deal with it.

Also, in the unlikely event we need to re-order the task->state bits
I'll do so without a moments hesitation, regardless of who consumes them
through the scheduler tracepoints, that's simply not stuff that should
be tied down.

The same for anything that tries to interpret task->prio through the
tracepoints.

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