Re: [PATCH -v5 14/14] futex: futex_unlock_pi() determinism

2017-03-13 Thread Peter Zijlstra
On Mon, Mar 13, 2017 at 03:25:52PM +0100, Thomas Gleixner wrote: > On Mon, 13 Mar 2017, Peter Zijlstra wrote: > > > On Tue, Mar 07, 2017 at 03:31:50PM +0100, Thomas Gleixner wrote: > > > On Sat, 4 Mar 2017, Peter Zijlstra wrote: > > > > > > > The problem with returning -EAGAIN when the waiter sta

Re: [PATCH -v5 14/14] futex: futex_unlock_pi() determinism

2017-03-13 Thread Thomas Gleixner
On Mon, 13 Mar 2017, Peter Zijlstra wrote: > On Tue, Mar 07, 2017 at 03:31:50PM +0100, Thomas Gleixner wrote: > > On Sat, 4 Mar 2017, Peter Zijlstra wrote: > > > > > The problem with returning -EAGAIN when the waiter state mismatches is > > > that it becomes very hard to proof a bounded execution

Re: [PATCH -v5 14/14] futex: futex_unlock_pi() determinism

2017-03-13 Thread Peter Zijlstra
On Tue, Mar 07, 2017 at 03:31:50PM +0100, Thomas Gleixner wrote: > On Sat, 4 Mar 2017, Peter Zijlstra wrote: > > > The problem with returning -EAGAIN when the waiter state mismatches is > > that it becomes very hard to proof a bounded execution time on the > > operation. And seeing that this is a

Re: [PATCH -v5 14/14] futex: futex_unlock_pi() determinism

2017-03-07 Thread Peter Zijlstra
On Tue, Mar 07, 2017 at 03:31:50PM +0100, Thomas Gleixner wrote: > On Sat, 4 Mar 2017, Peter Zijlstra wrote: > > > The problem with returning -EAGAIN when the waiter state mismatches is > > that it becomes very hard to proof a bounded execution time on the > > operation. And seeing that this is a

Re: [PATCH -v5 14/14] futex: futex_unlock_pi() determinism

2017-03-07 Thread Thomas Gleixner
On Sat, 4 Mar 2017, Peter Zijlstra wrote: > The problem with returning -EAGAIN when the waiter state mismatches is > that it becomes very hard to proof a bounded execution time on the > operation. And seeing that this is a RT operation, this is somewhat > important. > > While in practise it will

[PATCH -v5 14/14] futex: futex_unlock_pi() determinism

2017-03-04 Thread Peter Zijlstra
The problem with returning -EAGAIN when the waiter state mismatches is that it becomes very hard to proof a bounded execution time on the operation. And seeing that this is a RT operation, this is somewhat important. While in practise it will be very unlikely to ever really take more than one or t