On Sun, Apr 01, 2012 at 12:04:48PM +0200, Borislav Petkov wrote: > On Sun, Apr 01, 2012 at 12:33:21AM +0800, Paul E. McKenney wrote: > > Although there have been numerous complaints about the complexity of > > parallel programming (especially over the past 5-10 years), the plain > > truth is that the incremental complexity of parallel programming over > > that of sequential programming is not as large as is commonly believed. > > Despite that you might have heard, the mind-numbing complexity of modern > > computer systems is not due so much to there being multiple CPUs, but > > rather to there being any CPUs at all. In short, for the ultimate in > > computer-system simplicity, the optimal choice is NR_CPUS=0. > > > > This commit therefore limits kernel builds to zero CPUs. This change > > has the beneficial side effect of rendering all kernel bugs harmless. > > Furthermore, this commit enables additional beneficial changes, for > > example, the removal of those parts of the kernel that are not needed > > when there are zero CPUs. > > > > Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx> > > Reviewed-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx> > > Looks good, thanks for doing that. > > Btw, I just got confirmation from hw folk that we can actually give you > hardware support for that code with an upcoming CPU which has NR_CPUS=0 > cores. > > Oh, and additionally, we can disable some of those so getting into the > negative is also doable from the hw perspective, so feel free to explore > that side of the problem too. > > ACK. Cute! ;-) Thanx, Paul
