Re: [PATCH 08/14] sched: add latency tracing for -deadline tasks.

2013-11-27 Thread Steven Rostedt
On Wed, 27 Nov 2013 17:13:08 +0100 Ingo Molnar wrote: > > * Steven Rostedt wrote: > > > On Wed, 27 Nov 2013 16:46:00 +0100 > > Ingo Molnar wrote: > > > > > > > > * Peter Zijlstra wrote: > > > > > > > On Wed, Nov 27, 2013 at 04:35:19PM +0100, Ingo Molnar wrote: > > > > > So why does GCC th

Re: [PATCH 08/14] sched: add latency tracing for -deadline tasks.

2013-11-27 Thread Oleg Nesterov
On 11/27, Peter Zijlstra wrote: > > Anyway, yes GCC seems to behave as we 'expect' it to; I just can't find > the language spec actually guaranteeing this. And the kernel already assumes that gcc should do this, for example struct siginfo info = {}; in do_tkill(). (this initialization s

Re: [PATCH 08/14] sched: add latency tracing for -deadline tasks.

2013-11-27 Thread Ingo Molnar
* Steven Rostedt wrote: > On Wed, 27 Nov 2013 16:46:00 +0100 > Ingo Molnar wrote: > > > > > * Peter Zijlstra wrote: > > > > > On Wed, Nov 27, 2013 at 04:35:19PM +0100, Ingo Molnar wrote: > > > > So why does GCC then behave like this: > > > > > > I think because its a much saner behaviour;

Re: [PATCH 08/14] sched: add latency tracing for -deadline tasks.

2013-11-27 Thread Steven Rostedt
On Wed, 27 Nov 2013 10:56:16 -0500 Steven Rostedt wrote: > On Wed, 27 Nov 2013 16:46:00 +0100 > Ingo Molnar wrote: > > So from C99 standard §6.7.8 (Initialization)/21: > > > > "If there are fewer initializers in a brace-enclosed list than > > there are elements or members of an aggregat

Re: [PATCH 08/14] sched: add latency tracing for -deadline tasks.

2013-11-27 Thread Peter Zijlstra
On Wed, Nov 27, 2013 at 10:56:16AM -0500, Steven Rostedt wrote: > > So from C99 standard §6.7.8 (Initialization)/21: > > > > "If there are fewer initializers in a brace-enclosed list than > > there are elements or members of an aggregate, or fewer characters > > in a string literal used

Re: [PATCH 08/14] sched: add latency tracing for -deadline tasks.

2013-11-27 Thread Peter Zijlstra
On Wed, Nov 27, 2013 at 04:46:00PM +0100, Ingo Molnar wrote: > > * Peter Zijlstra wrote: > > > On Wed, Nov 27, 2013 at 04:35:19PM +0100, Ingo Molnar wrote: > > > So why does GCC then behave like this: > > > > I think because its a much saner behaviour; also it might still be the > > spec actual

Re: [PATCH 08/14] sched: add latency tracing for -deadline tasks.

2013-11-27 Thread Steven Rostedt
On Wed, 27 Nov 2013 16:46:00 +0100 Ingo Molnar wrote: > > * Peter Zijlstra wrote: > > > On Wed, Nov 27, 2013 at 04:35:19PM +0100, Ingo Molnar wrote: > > > So why does GCC then behave like this: > > > > I think because its a much saner behaviour; also it might still be the > > spec actually sa

Re: [PATCH 08/14] sched: add latency tracing for -deadline tasks.

2013-11-27 Thread Ingo Molnar
* Peter Zijlstra wrote: > On Wed, Nov 27, 2013 at 04:35:19PM +0100, Ingo Molnar wrote: > > So why does GCC then behave like this: > > I think because its a much saner behaviour; also it might still be the > spec actually says this, its a somewhat opaque text. > > Anyway, yes GCC seems to behav

Re: [PATCH 08/14] sched: add latency tracing for -deadline tasks.

2013-11-27 Thread Ingo Molnar
and even this works: triton:~> cat test.c struct foo { int a; int b; }; int litter_our_stack(void) { volatile struct foo x = { .a = 1, .b = 2 }; return x.b; } int test_code(void) { volatile struct foo x = { .a = 1, /* .b not initialized explicitly */ };

Re: [PATCH 08/14] sched: add latency tracing for -deadline tasks.

2013-11-27 Thread Peter Zijlstra
On Wed, Nov 27, 2013 at 04:35:19PM +0100, Ingo Molnar wrote: > So why does GCC then behave like this: I think because its a much saner behaviour; also it might still be the spec actually says this, its a somewhat opaque text. Anyway, yes GCC seems to behave as we 'expect' it to; I just can't find

Re: [PATCH 08/14] sched: add latency tracing for -deadline tasks.

2013-11-27 Thread Ingo Molnar
* Peter Zijlstra wrote: > On Wed, Nov 27, 2013 at 03:34:35PM +0100, Ingo Molnar wrote: > > > > * Peter Zijlstra wrote: > > > > > On Wed, Nov 27, 2013 at 09:16:47AM -0500, Steven Rostedt wrote: > > > > On Wed, 27 Nov 2013 14:43:45 +0100 > > > > Juri Lelli wrote: > > > > diff --git a/kernel/tr

Re: [PATCH 08/14] sched: add latency tracing for -deadline tasks.

2013-11-27 Thread Steven Rostedt
On Wed, 27 Nov 2013 15:26:49 +0100 Peter Zijlstra wrote: > On Wed, Nov 27, 2013 at 09:16:47AM -0500, Steven Rostedt wrote: > > On Wed, 27 Nov 2013 14:43:45 +0100 > > Juri Lelli wrote: > > diff --git a/kernel/trace/trace_selftest.c b/kernel/trace/trace_selftest.c > > > index f76f8d6..ad94604 1006

Re: [PATCH 08/14] sched: add latency tracing for -deadline tasks.

2013-11-27 Thread Peter Zijlstra
On Wed, Nov 27, 2013 at 03:34:35PM +0100, Ingo Molnar wrote: > > * Peter Zijlstra wrote: > > > On Wed, Nov 27, 2013 at 09:16:47AM -0500, Steven Rostedt wrote: > > > On Wed, 27 Nov 2013 14:43:45 +0100 > > > Juri Lelli wrote: > > > diff --git a/kernel/trace/trace_selftest.c b/kernel/trace/trace_s

Re: [PATCH 08/14] sched: add latency tracing for -deadline tasks.

2013-11-27 Thread Ingo Molnar
* Peter Zijlstra wrote: > On Wed, Nov 27, 2013 at 09:16:47AM -0500, Steven Rostedt wrote: > > On Wed, 27 Nov 2013 14:43:45 +0100 > > Juri Lelli wrote: > > diff --git a/kernel/trace/trace_selftest.c b/kernel/trace/trace_selftest.c > > > index f76f8d6..ad94604 100644 > > > --- a/kernel/trace/trac

Re: [PATCH 08/14] sched: add latency tracing for -deadline tasks.

2013-11-27 Thread Peter Zijlstra
On Wed, Nov 27, 2013 at 09:16:47AM -0500, Steven Rostedt wrote: > On Wed, 27 Nov 2013 14:43:45 +0100 > Juri Lelli wrote: > diff --git a/kernel/trace/trace_selftest.c b/kernel/trace/trace_selftest.c > > index f76f8d6..ad94604 100644 > > --- a/kernel/trace/trace_selftest.c > > +++ b/kernel/trace/tra

Re: [PATCH 08/14] sched: add latency tracing for -deadline tasks.

2013-11-27 Thread Juri Lelli
On 11/27/2013 03:16 PM, Steven Rostedt wrote: > On Wed, 27 Nov 2013 14:43:45 +0100 > Juri Lelli wrote: > diff --git a/kernel/trace/trace_selftest.c b/kernel/trace/trace_selftest.c >> index f76f8d6..ad94604 100644 >> --- a/kernel/trace/trace_selftest.c >> +++ b/kernel/trace/trace_selftest.c >> @@ -

Re: [PATCH 08/14] sched: add latency tracing for -deadline tasks.

2013-11-27 Thread Steven Rostedt
On Wed, 27 Nov 2013 14:43:45 +0100 Juri Lelli wrote: diff --git a/kernel/trace/trace_selftest.c b/kernel/trace/trace_selftest.c > index f76f8d6..ad94604 100644 > --- a/kernel/trace/trace_selftest.c > +++ b/kernel/trace/trace_selftest.c > @@ -1023,16 +1023,16 @@ trace_selftest_startup_nop(struct tr

Re: [PATCH 08/14] sched: add latency tracing for -deadline tasks.

2013-11-27 Thread Juri Lelli
On 11/20/2013 10:33 PM, Steven Rostedt wrote: > On Thu, 7 Nov 2013 14:43:42 +0100 > Juri Lelli wrote: > > >> +/* >> + * Semantic is like this: >> + * - wakeup tracer handles all tasks in the system, independently >> + *from their scheduling class; >> + * - wakeup_rt tr

Re: [PATCH 08/14] sched: add latency tracing for -deadline tasks.

2013-11-20 Thread Steven Rostedt
On Thu, 7 Nov 2013 14:43:42 +0100 Juri Lelli wrote: > + /* > + * Semantic is like this: > + * - wakeup tracer handles all tasks in the system, independently > + *from their scheduling class; > + * - wakeup_rt tracer handles tasks belonging to sched_dl and > +

[PATCH 08/14] sched: add latency tracing for -deadline tasks.

2013-11-07 Thread Juri Lelli
From: Dario Faggioli It is very likely that systems that wants/needs to use the new SCHED_DEADLINE policy also want to have the scheduling latency of the -deadline tasks under control. For this reason a new version of the scheduling wakeup latency, called "wakeup_dl", is introduced. As a conseq

[PATCH 08/14] sched: add latency tracing for -deadline tasks.

2013-10-14 Thread Juri Lelli
From: Dario Faggioli It is very likely that systems that wants/needs to use the new SCHED_DEADLINE policy also want to have the scheduling latency of the -deadline tasks under control. For this reason a new version of the scheduling wakeup latency, called "wakeup_dl", is introduced. As a conseq

[PATCH 08/14] sched: add latency tracing for -deadline tasks.

2013-02-11 Thread Juri Lelli
From: Dario Faggioli It is very likely that systems that wants/needs to use the new SCHED_DEADLINE policy also want to have the scheduling latency of the -deadline tasks under control. For this reason a new version of the scheduling wakeup latency, called "wakeup_dl", is introduced. As a conseq