* Re: [PATCH documentation 1/2] nohz1: Add documentation. [not found] ` <5166EF74.4030106@linux.intel.com> @ 2013-04-11 18:27 ` Paul E. McKenney 2013-04-11 18:43 ` Dipankar Sarma 0 siblings, 1 reply; 3+ messages in thread From: Paul E. McKenney @ 2013-04-11 18:27 UTC (permalink / raw) To: Arjan van de Ven Cc: linux-kernel, mingo, laijs, dipankar, akpm, mathieu.desnoyers, josh, niv, tglx, peterz, rostedt, Valdis.Kletnieks, dhowells, edumazet, darren, fweisbec, sbw, Borislav Petkov, Kevin Hilman, Christoph Lameter, arnd, Robin.Randhawa, linux-rt-users 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 used with non-tickless system (the break even times are > quite a bit less than even 1 msec). > I can't imagine that ARM is worse on this, at which point the statement above is highly dubious Interesting point, and I freely admit that I don't have full knowledge of the energy-consumption characteristics of all the architectures that Linux supports. Adding a few of the ARM guys on CC for their take, plus linux-rt-users. If there are no objections, I will delete point 2 above as Arjan suggests. Thanx, Paul ^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH documentation 1/2] nohz1: Add documentation. 2013-04-11 18:27 ` [PATCH documentation 1/2] nohz1: Add documentation Paul E. McKenney @ 2013-04-11 18:43 ` Dipankar Sarma 2013-04-11 19:14 ` Paul E. McKenney 0 siblings, 1 reply; 3+ messages in thread From: Dipankar Sarma @ 2013-04-11 18:43 UTC (permalink / raw) To: Paul E. McKenney Cc: Arjan van de Ven, linux-kernel, mingo, laijs, akpm, mathieu.desnoyers, josh, niv, tglx, peterz, rostedt, Valdis.Kletnieks, dhowells, edumazet, darren, fweisbec, sbw, Borislav Petkov, Kevin Hilman, Christoph Lameter, arnd, Robin.Randhawa, linux-rt-users 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 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 less than even 1 msec). > > I can't imagine that ARM is worse on this, at which point the statement above is highly dubious > > Interesting point, and I freely admit that I don't have full knowledge > of the energy-consumption characteristics of all the architectures that > Linux supports. Adding a few of the ARM guys on CC for their take, > plus linux-rt-users. > > If there are no objections, I will delete point 2 above as Arjan suggests. What Arjan said will also be true for Linux on Power systems. I am not sure "many architectures" would be the right way to characterize it. Thanks Dipankar ^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH documentation 1/2] nohz1: Add documentation. 2013-04-11 18:43 ` Dipankar Sarma @ 2013-04-11 19:14 ` Paul E. McKenney 0 siblings, 0 replies; 3+ messages in thread From: Paul E. McKenney @ 2013-04-11 19:14 UTC (permalink / raw) To: Dipankar Sarma Cc: Arjan van de Ven, linux-kernel, mingo, laijs, akpm, mathieu.desnoyers, josh, niv, tglx, peterz, rostedt, Valdis.Kletnieks, dhowells, edumazet, darren, fweisbec, sbw, Borislav Petkov, Kevin Hilman, Christoph Lameter, arnd, Robin.Randhawa, linux-rt-users 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 > > > >+ 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 less than even 1 msec). > > > I can't imagine that ARM is worse on this, at which point the statement above is highly dubious > > > > Interesting point, and I freely admit that I don't have full knowledge > > of the energy-consumption characteristics of all the architectures that > > Linux supports. Adding a few of the ARM guys on CC for their take, > > plus linux-rt-users. > > > > If there are no objections, I will delete point 2 above as Arjan suggests. > > What Arjan said will also be true for Linux on Power systems. I am not > sure "many architectures" would be the right way to characterize it. Very well, I count one non-objection to Arjan's suggestion. ;-) Thanx, Paul ^ permalink raw reply [flat|nested] 3+ messages in thread
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2013-04-11 18:27 ` [PATCH documentation 1/2] nohz1: Add documentation Paul E. McKenney
2013-04-11 18:43 ` Dipankar Sarma
2013-04-11 19:14 ` Paul E. McKenney
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