From: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Greg KH <greg@kroah.com>,
devel@driverdev.osuosl.org, lttng-dev@lists.lttng.org,
Ingo Molnar <mingo@elte.hu>,
linux-kernel@vger.kernel.org, Darren Hart <darren@dvhart.com>
Subject: Re: [PATCH 09/11] sched: export task_prio to GPL modules
Date: Thu, 1 Dec 2011 17:36:07 -0500 [thread overview]
Message-ID: <20111201223607.GF10552@Krystal> (raw)
In-Reply-To: <20111201221500.GC10552@Krystal>
* Mathieu Desnoyers (mathieu.desnoyers@efficios.com) wrote:
> * Peter Zijlstra (peterz@infradead.org) wrote:
> > On Thu, 2011-12-01 at 17:04 -0500, Mathieu Desnoyers wrote:
> > > * Peter Zijlstra (peterz@infradead.org) wrote:
> > > > On Thu, 2011-12-01 at 16:41 -0500, Mathieu Desnoyers wrote:
> > > > > LTTng needs this symbol to prepend the current task dynamic priority
> > > > > value to events (optional context information).
> > > >
> > > > I absolutely detest exporting such stuff. It propagates the idea that
> > > > task prio actually means something. Also, modules really shouldn't care.
> > >
> > > People debugging their SCHED_FIFO/SCHED_RR applications, as well as
> > > users of priority-inheritance futexes, may happen to find this
> > > information extremely useful.
> > >
> > > Just saying...
> >
> > Right until the moment we go do deadlines.. Anyway, it still doesn't
> > make sense, your sched_switch() tracepoint handler gets this
> > information, why do you need this export at all?
>
> If you don't want to trace sched_switch, but just conveniently prepend
> this information to all your events, then lttng lets you dynamically
> target this extra bit of information. Note that it's not a mandatory
> event field: I call those "context" fields that the tracer prepends to
> events, as requested by the user.
One more point:
compudj@thinkos:/proc/204$ cat sched
khubd (204, #threads: 1)
---------------------------------------------------------
se.exec_start : 3355267.749529
se.vruntime : 113843.899081
se.sum_exec_runtime : 12.820702
nr_switches : 386
nr_voluntary_switches : 385
nr_involuntary_switches : 1
se.load.weight : 1024
policy : 0
prio : 120
clock-delta : 130
So what you are saying is that it is fine to export task_prio to
_userspace_, thus making it part of the ABI, but it's not OK to export
it to GPL modules ?
Weird huh ?
Mathieu
>
> Thanks,
>
> Mathieu
>
>
> --
> Mathieu Desnoyers
> Operating System Efficiency R&D Consultant
> EfficiOS Inc.
> http://www.efficios.com
--
Mathieu Desnoyers
Operating System Efficiency R&D Consultant
EfficiOS Inc.
http://www.efficios.com
next prev parent reply other threads:[~2011-12-01 22:36 UTC|newest]
Thread overview: 61+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <1322775683-8741-1-git-send-email-mathieu.desnoyers@efficios.com>
2011-12-01 21:41 ` [PATCH 01/11] mm: export vmalloc_sync_all symbol to GPL modules Mathieu Desnoyers
2011-12-01 21:41 ` Mathieu Desnoyers
2011-12-01 21:57 ` Christoph Hellwig
2011-12-01 21:57 ` Christoph Hellwig
2011-12-01 22:13 ` Greg KH
2011-12-01 22:13 ` Greg KH
2011-12-01 22:19 ` Mathieu Desnoyers
2011-12-01 22:19 ` Mathieu Desnoyers
2011-12-01 22:41 ` Greg KH
2011-12-01 22:41 ` Greg KH
2011-12-01 22:28 ` Christoph Hellwig
2011-12-01 22:28 ` Christoph Hellwig
2011-12-01 23:00 ` Greg KH
2011-12-01 23:00 ` Greg KH
2011-12-01 21:57 ` Christoph Hellwig
2011-12-01 21:57 ` Christoph Hellwig
2011-12-01 21:57 ` Christoph Hellwig
2011-12-01 21:41 ` [PATCH 03/11] fs/splice: export splice_to_pipe " Mathieu Desnoyers
2011-12-02 7:19 ` Jens Axboe
2011-12-02 12:32 ` Mathieu Desnoyers
2011-12-01 21:41 ` [PATCH 09/11] sched: export task_prio " Mathieu Desnoyers
2011-12-01 21:56 ` Peter Zijlstra
2011-12-01 22:04 ` Mathieu Desnoyers
2011-12-01 22:10 ` Peter Zijlstra
2011-12-01 22:15 ` Mathieu Desnoyers
2011-12-01 22:36 ` Mathieu Desnoyers [this message]
2011-12-01 23:05 ` Peter Zijlstra
2011-12-02 13:51 ` Mathieu Desnoyers
2011-12-01 23:06 ` Peter Zijlstra
2011-12-01 23:18 ` Greg KH
2011-12-01 23:47 ` Mathieu Desnoyers
2011-12-01 22:14 ` Greg KH
2011-12-01 22:20 ` Mathieu Desnoyers
2011-12-01 23:07 ` Peter Zijlstra
2011-12-01 23:17 ` Greg KH
2011-12-05 14:17 ` Ingo Molnar
2011-12-06 21:44 ` Greg KH
2011-12-08 5:23 ` Ingo Molnar
2011-12-08 23:27 ` Greg KH
2011-12-19 10:49 ` Ingo Molnar
2011-12-19 15:30 ` [lttng-dev] " Mathieu Desnoyers
2011-12-20 11:08 ` Ingo Molnar
2011-12-20 21:46 ` Frank Rowand
2011-12-23 10:51 ` Ingo Molnar
2011-12-21 18:47 ` Aaron Spear
2011-12-21 18:58 ` Christoph Hellwig
2011-12-23 16:46 ` Perf ABI (was: Re: [lttng-dev] [PATCH 09/11] sched: export task_prio to GPL modules) Mathieu Desnoyers
2011-12-23 17:21 ` Ted Ts'o
2011-12-23 18:16 ` Mathieu Desnoyers
2011-12-25 17:46 ` Ted Ts'o
2012-01-12 14:09 ` Mathieu Desnoyers
2012-01-12 14:54 ` Steven Rostedt
2012-01-12 15:39 ` [lttng-dev] Perf ABI (was: " Mathieu Desnoyers
2012-01-12 15:53 ` Steven Rostedt
2012-01-12 15:59 ` Steven Rostedt
2012-01-12 16:27 ` Mathieu Desnoyers
2012-01-12 16:34 ` Steven Rostedt
2012-01-12 20:00 ` Greg KH
2012-01-16 8:55 ` Ingo Molnar
2011-12-07 22:57 ` [PATCH 09/11] sched: export task_prio to GPL modules Mathieu Desnoyers
2011-12-08 5:40 ` Ingo Molnar
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