2013/4/11 Paul E. McKenney :
> From: "Paul E. McKenney"
>
> Signed-off-by: Paul E. McKenney
> Cc: Frederic Weisbecker
> Cc: Steven Rostedt
> Cc: Borislav Petkov
> Cc: Arjan van de Ven
> Cc: Kevin Hilman
> Cc: Christoph Lameter
> ---
There have been some significant interest and amount of r
On Fri, Apr 19, 2013 at 02:01:49PM -0700, Kevin Hilman wrote:
> "Paul E. McKenney" writes:
>
> > +KNOWN ISSUES
>
> [...]
>
> > +o Unless all CPUs are idle, at least one CPU must keep the
> > + scheduling-clock interrupt going in order to support accurate
> > + timekeeping.
>
> At least wi
"Paul E. McKenney" writes:
> +KNOWN ISSUES
[...]
> +oUnless all CPUs are idle, at least one CPU must keep the
> + scheduling-clock interrupt going in order to support accurate
> + timekeeping.
At least with the implementation I'm using (Frederic's 3.9-nohz1
branch), at least one CP
On 4/15/2013 9:53 AM, Christoph Lameter wrote:
On Mon, 15 Apr 2013, Arjan van de Ven wrote:
to put the "cost" into perspective; programming a timer in one-shot mode
is some math on the cpu (to go from kernel time to hardware time),
which is a multiply and a shift (or a divide), and then actuall
On Mon, 15 Apr 2013, Arjan van de Ven wrote:
> to put the "cost" into perspective; programming a timer in one-shot mode
> is some math on the cpu (to go from kernel time to hardware time),
> which is a multiply and a shift (or a divide), and then actually
> programming the hardware, which is at th
On 4/15/2013 9:00 AM, Christoph Lameter wrote:
On Fri, 12 Apr 2013, Arjan van de Ven wrote:
but arguably, that's because of HRTIMERS more than NOHZ
(e.g. I bet we still turn off periodic even for nohz as long as hrtimers are
enabled)
If we are able to only get rid of one timer tick on average
On Fri, 12 Apr 2013, Arjan van de Ven wrote:
> but arguably, that's because of HRTIMERS more than NOHZ
> (e.g. I bet we still turn off periodic even for nohz as long as hrtimers are
> enabled)
If we are able to only get rid of one timer tick on average with dynticks
then I would think that is eno
On Fri, Apr 12, 2013 at 10:56:35AM -0700, Arjan van de Ven wrote:
>
> >
> >
> >1. It increases the number of instructions executed on the path
> > to and from the idle loop.
> >
> >2. On many architectures, dyntick-idl
1. It increases the number of instructions executed on the path
to and from the idle loop.
2. On many architectures, dyntick-idle mode also increases the
number of times that clocks must be repro
On Fri, Apr 12, 2013 at 10:05:04AM +0200, Peter Zijlstra wrote:
> On Thu, 2013-04-11 at 12:13 -0700, Paul E. McKenney wrote:
> > > > +2. Many architectures will place dyntick-idle CPUs into deep sleep
> > > > + states, which further degrades from-idle transition latencies.
> > >
> > > Above you
On Thu, 2013-04-11 at 12:13 -0700, Paul E. McKenney wrote:
> > > +2. Many architectures will place dyntick-idle CPUs into deep sleep
> > > + states, which further degrades from-idle transition latencies.
> >
> > Above you say "to and from the idle loop", now it is from-idle. Simply say:
> >
> >
On Thu, Apr 11, 2013 at 10:19:56PM +0200, Borislav Petkov wrote:
> On Thu, Apr 11, 2013 at 12:13:55PM -0700, Paul E. McKenney wrote:
> > Thank you for the careful review and helpful comments!
>
> Sure, agreed with all your comments - I think we've so beaten the hell
> out of this, it's not even fu
On Thu, Apr 11, 2013 at 12:13:55PM -0700, Paul E. McKenney wrote:
> Thank you for the careful review and helpful comments!
Sure, agreed with all your comments - I think we've so beaten the hell
out of this, it's not even funny. ;-)
Reviewed-by: Borislav Petkov
--
Regards/Gruss,
Boris.
Sen
On Fri, Apr 12, 2013 at 12:13:13AM +0530, Dipankar Sarma wrote:
> On Thu, Apr 11, 2013 at 11:27:27AM -0700, Paul E. McKenney wrote:
> > On Thu, Apr 11, 2013 at 10:14:28AM -0700, Arjan van de Ven wrote:
> > > >+2. Many architectures will place dyntick-idle CPUs into deep sleep
> > > >+s
On Thu, Apr 11, 2013 at 08:25:02PM +0200, Borislav Petkov wrote:
> Ok,
>
> here's some more Savel fun, feel free to take whatever you like. :)
;-) ;-) ;-)
> On Thu, Apr 11, 2013 at 09:05:58AM -0700, Paul E. McKenney wrote:
> > From: "Paul E. McKenney"
> >
> > Signed-off-by: Paul E. McKenney
>
On Thu, Apr 11, 2013 at 11:27:27AM -0700, Paul E. McKenney wrote:
> On Thu, Apr 11, 2013 at 10:14:28AM -0700, Arjan van de Ven wrote:
> > >+2.Many architectures will place dyntick-idle CPUs into deep sleep
> > >+ states, which further degrades from-idle transition latencies.
> > >+
> > I t
On Thu, Apr 11, 2013 at 10:14:28AM -0700, Arjan van de Ven wrote:
> >+2. Many architectures will place dyntick-idle CPUs into deep sleep
> >+states, which further degrades from-idle transition latencies.
> >+
> I think this part should just be deleted.
> On x86, the deeper idle states are even
Ok,
here's some more Savel fun, feel free to take whatever you like. :)
On Thu, Apr 11, 2013 at 09:05:58AM -0700, Paul E. McKenney wrote:
> From: "Paul E. McKenney"
>
> Signed-off-by: Paul E. McKenney
> Cc: Frederic Weisbecker
> Cc: Steven Rostedt
> Cc: Borislav Petkov
> Cc: Arjan van de Ve
+2. Many architectures will place dyntick-idle CPUs into deep sleep
+ states, which further degrades from-idle transition latencies.
+
I think this part should just be deleted.
On x86, the deeper idle states are even used with non-tickless system (the
break even times are
quite a bit l
On Thu, Apr 11, 2013 at 09:48:45AM -0700, Randy Dunlap wrote:
> On 04/11/2013 09:05 AM, Paul E. McKenney wrote:
> >From: "Paul E. McKenney"
> >
> >Signed-off-by: Paul E. McKenney
> >Cc: Frederic Weisbecker
> >Cc: Steven Rostedt
> >Cc: Borislav Petkov
> >Cc: Arjan van de Ven
> >Cc: Kevin Hilma
On 04/11/2013 09:05 AM, Paul E. McKenney wrote:
From: "Paul E. McKenney"
Signed-off-by: Paul E. McKenney
Cc: Frederic Weisbecker
Cc: Steven Rostedt
Cc: Borislav Petkov
Cc: Arjan van de Ven
Cc: Kevin Hilman
Cc: Christoph Lameter
---
Documentation/timers/NO_HZ.txt | 245 +
From: "Paul E. McKenney"
Signed-off-by: Paul E. McKenney
Cc: Frederic Weisbecker
Cc: Steven Rostedt
Cc: Borislav Petkov
Cc: Arjan van de Ven
Cc: Kevin Hilman
Cc: Christoph Lameter
---
Documentation/timers/NO_HZ.txt | 245 +
1 file changed, 245 inser
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